Optimized timer implementation

1 files changed, 2901 insertions, 0 deletions

diff --git a/erts/emulator/beam/erl_hl_timer.c b/erts/emulator/beam/erl_hl_timer.c
new file mode 100644
index 0000000000..2245799819
--- /dev/null
+++ b/erts/emulator/beam/erl_hl_timer.c
@@ -0,0 +1,2901 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2015. All Rights Reserved.
+ * 
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ * 
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * %CopyrightEnd%
+ */
+
+/*
+ * Description: High level timers implementing BIF timers
+ *              as well as process and port timers.
+ *
+ * Author: 	Rickard Green
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include "sys.h"
+#include "global.h"
+#include "bif.h"
+#include "erl_bif_unique.h"
+#define ERTS_WANT_TIMER_WHEEL_API
+#include "erl_time.h"
+#include "erl_hl_timer.h"
+
+#define ERTS_TMR_CHECK_CANCEL_ON_CREATE 0
+
+#if 0
+#  define ERTS_HLT_HARD_DEBUG
+#endif
+#if 0
+#  define ERTS_HLT_DEBUG
+#endif
+
+#if defined(ERTS_HLT_HARD_DEBUG) || defined(DEBUG)
+#  if defined(ERTS_HLT_HARD_DEBUG)
+#    undef ERTS_RBT_HARD_DEBUG
+#    define ERTS_RBT_HARD_DEBUG 1
+#  endif
+#  ifndef ERTS_HLT_DEBUG
+#    define ERTS_HLT_DEBUG 1
+#  endif
+#endif
+
+#undef ERTS_HLT_ASSERT
+#if defined(ERTS_HLT_DEBUG)
+#  define ERTS_HLT_ASSERT(E) ERTS_ASSERT(E)
+#  undef ERTS_RBT_DEBUG
+#  define ERTS_RBT_DEBUG
+#else
+#  define ERTS_HLT_ASSERT(E) ((void) 1)
+#endif
+
+#if defined(ERTS_HLT_HARD_DEBUG) && defined(__GNUC__)
+#warning "* * * * * * * * * * * * * * * * * *"
+#warning "* ERTS_HLT_HARD_DEBUG IS ENABLED! *"
+#warning "* * * * * * * * * * * * * * * * * *"
+#endif
+
+#ifdef ERTS_HLT_HARD_DEBUG
+#  define ERTS_HLT_HDBG_CHK_SRV(SRV) hdbg_chk_srv((SRV))
+static void hdbg_chk_srv(ErtsHLTimerService *srv);
+#else
+#  define ERTS_HLT_HDBG_CHK_SRV(SRV) ((void) 1)
+#endif
+
+#if ERTS_REF_NUMBERS != 3
+#error "ERTS_REF_NUMBERS changed. Update me..."
+#endif
+
+#define ERTS_BIF_TIMER_SHORT_TIME 5000
+
+#ifdef ERTS_SMP
+#  define ERTS_HLT_SMP_MEMBAR_LoadLoad_LoadStore \
+    ETHR_MEMBAR(ETHR_LoadLoad|ETHR_LoadStore)
+#else
+#  define ERTS_HLT_SMP_MEMBAR_LoadLoad_LoadStore
+#endif
+
+/* Bit 0 to 9 contains scheduler id (see mask below) */
+#define ERTS_TMR_ROFLG_HLT		(((Uint32) 1) << 10)
+#define ERTS_TMR_ROFLG_BIF_TMR		(((Uint32) 1) << 11)
+#define ERTS_TMR_ROFLG_ABIF_TMR		(((Uint32) 1) << 12)
+#define ERTS_TMR_ROFLG_PRE_ALC		(((Uint32) 1) << 13)
+#define ERTS_TMR_ROFLG_REG_NAME		(((Uint32) 1) << 14)
+#define ERTS_TMR_ROFLG_PROC		(((Uint32) 1) << 15)
+#define ERTS_TMR_ROFLG_PORT		(((Uint32) 1) << 16)
+
+#define ERTS_TMR_ROFLG_SID_MASK	\
+    (ERTS_TMR_ROFLG_HLT - (Uint32) 1)
+
+#define ERTS_TMR_STATE_ACTIVE		((erts_aint32_t) 0)
+#define ERTS_TMR_STATE_CANCELED		((erts_aint32_t) 1)
+#define ERTS_TMR_STATE_TIMED_OUT	((erts_aint32_t) 2)
+
+typedef struct ErtsHLTimer_ ErtsHLTimer;
+
+#define ERTS_HLT_PFLG_RED		(((UWord) 1) << 0)
+#define ERTS_HLT_PFLG_SAME_TIME		(((UWord) 1) << 1)
+
+#define ERTS_HLT_PFLGS_MASK \
+    (ERTS_HLT_PFLG_RED|ERTS_HLT_PFLG_SAME_TIME)
+
+#define ERTS_HLT_PFIELD_NOT_IN_TABLE	(~((UWord) 0))
+
+typedef struct {
+    UWord parent; /* parent pointer and flags... */
+    union {
+	struct {
+	    ErtsHLTimer *right;
+	    ErtsHLTimer *left;
+	} t;
+	struct {
+	    ErtsHLTimer *prev;
+	    ErtsHLTimer *next;
+	} l;
+    } u;
+    ErtsHLTimer *same_time;
+} ErtsHLTimerTimeTree;
+
+typedef struct {
+    UWord parent; /* parent pointer and flags... */
+    ErtsHLTimer *right;
+    ErtsHLTimer *left;
+} ErtsHLTimerTree;
+
+typedef struct {
+    Uint32 roflgs;
+    erts_smp_atomic32_t refc;
+    union {
+	erts_atomic_t next;
+    } u;
+} ErtsTmrHead;
+
+struct ErtsHLTimer_ {
+    ErtsTmrHead head; /* NEED to be first! */
+    union {
+	ErtsThrPrgrLaterOp cleanup;
+	ErtsHLTimerTimeTree tree;
+    } time;
+    ErtsMonotonicTime timeout;
+    union {
+	Process *proc;
+	Port *port;
+	Eterm name;
+    } receiver;
+
+#ifdef ERTS_HLT_HARD_DEBUG
+    int pending_timeout;
+#endif
+
+    erts_smp_atomic32_t state;
+
+    /* BIF timer only fields follow... */
+    struct {
+	Uint32 refn[ERTS_REF_NUMBERS];
+	ErtsHLTimerTree proc_tree;
+	ErtsHLTimerTree tree;
+	Eterm message;
+	ErlHeapFragment *bp;
+    } btm;
+    struct {
+	Eterm accessor;
+	ErtsHLTimerTree tree;
+    } abtm;
+};
+
+#define ERTS_HL_PTIMER_SIZE offsetof(ErtsHLTimer, btm)
+#define ERTS_BIF_TIMER_SIZE offsetof(ErtsHLTimer, abtm)
+#define ERTS_ABIF_TIMER_SIZE sizeof(ErtsHLTimer)
+
+typedef struct {
+    ErtsTmrHead head; /* NEED to be first! */
+    void *p;
+    ErtsTWheelTimer tw_tmr;
+} ErtsTWTimer;
+
+typedef union {
+    ErtsTmrHead head;
+    ErtsHLTimer hlt;
+    ErtsTWTimer twt;
+} ErtsTimer;
+
+#ifdef SMALL_MEMORY
+#define BIF_TIMER_PREALC_SZ	10
+#define PTIMER_PREALC_SZ	10
+#else
+#define BIF_TIMER_PREALC_SZ	100
+#define PTIMER_PREALC_SZ	100
+#endif
+
+ERTS_SCHED_PREF_PALLOC_IMPL(bif_timer_pre,
+			    ErtsHLTimer,
+			    BIF_TIMER_PREALC_SZ)
+
+ERTS_SCHED_PREF_QUICK_ALLOC_IMPL(tw_timer,
+				 ErtsTWTimer,
+				 PTIMER_PREALC_SZ,
+				 ERTS_ALC_T_LL_PTIMER)
+
+#ifdef ERTS_HLT_DEBUG
+#define ERTS_TMR_TIMEOUT_YIELD_LIMIT 5
+#else
+#define ERTS_TMR_TIMEOUT_YIELD_LIMIT 100
+#endif
+#define ERTS_TMR_CANCELED_TIMER_LIMIT 100
+#define ERTS_TMR_CANCELED_TIMER_SMALL_LIMIT 5
+
+#define ERTS_TMR_TIMEOUT_YIELD_STATE_T same_time_list_yield_state_t
+#define ERTS_TMR_YIELDING_TIMEOUT_STATE_INITER {NULL, {0}}
+typedef struct {
+    int dummy;
+} ERTS_TMR_TIMEOUT_YIELD_STATE_T;
+
+typedef struct {
+    ErtsTmrHead marker;
+    erts_atomic_t last;
+} ErtsHLTCncldTmrQTail;
+
+#ifdef ERTS_SMP
+
+typedef struct {
+    /*
+     * This structure needs to be cache line aligned for best
+     * performance.
+     */
+    union {
+	/*
+	 * Modified by threads returning canceled
+	 * timers to this timer service.
+	 */
+	ErtsHLTCncldTmrQTail data;
+	char align__[ERTS_ALC_CACHE_LINE_ALIGN_SIZE(
+		sizeof(ErtsHLTCncldTmrQTail))];
+    } tail;
+    /*
+     * Everything below this point is *only* accessed by the
+     * thread managing this timer service.
+     */
+    struct {
+	ErtsTimer *first;
+	ErtsTimer *unref_end;
+	struct {
+	    ErtsThrPrgrVal thr_progress;
+	    int thr_progress_reached;
+	    ErtsTimer *unref_end;
+	} next;
+	int used_marker;
+    } head;
+} ErtsHLTCncldTmrQ;
+
+#endif /* ERTS_SMP */
+
+typedef struct {
+    ErtsHLTimer *root;
+    ERTS_TMR_TIMEOUT_YIELD_STATE_T state;
+} ErtsYieldingTimeoutState;
+
+struct ErtsHLTimerService_ {
+#ifdef ERTS_SMP
+    ErtsHLTCncldTmrQ canceled_queue;
+#endif
+    ErtsHLTimer *time_tree;
+    ErtsHLTimer *btm_tree;
+    ErtsHLTimer *next_timeout;
+    ErtsYieldingTimeoutState yield;
+    ErtsTWheelTimer service_timer;
+};
+
+static ERTS_INLINE int
+refn_is_lt(Uint32 *x, Uint32 *y)
+{
+    /* !0 if x < y */
+    if (x[2] < y[2])
+	return 1;
+    if (x[2] != y[2])
+	return 0;
+    if (x[1] < y[1])
+	return 1;
+    if (x[1] != y[1])
+	return 0;
+    return x[0] < y[0];
+}
+
+#define ERTS_RBT_PREFIX time
+#define ERTS_RBT_T ErtsHLTimer
+#define ERTS_RBT_KEY_T ErtsMonotonicTime
+#define ERTS_RBT_FLAGS_T UWord
+#define ERTS_RBT_INIT_EMPTY_TNODE(T)					\
+    do {								\
+	(T)->time.tree.parent = (UWord) NULL;				\
+	(T)->time.tree.u.t.right = NULL;				\
+	(T)->time.tree.u.t.left = NULL;					\
+    } while (0)
+#define ERTS_RBT_IS_RED(T)						\
+    ((int) ((T)->time.tree.parent & ERTS_HLT_PFLG_RED))
+#define ERTS_RBT_SET_RED(T)						\
+    ((T)->time.tree.parent |= ERTS_HLT_PFLG_RED)
+#define ERTS_RBT_IS_BLACK(T)						\
+    (!ERTS_RBT_IS_RED((T)))
+#define ERTS_RBT_SET_BLACK(T)						\
+    ((T)->time.tree.parent &= ~ERTS_HLT_PFLG_RED)
+#define ERTS_RBT_GET_FLAGS(T)						\
+    ((T)->time.tree.parent & ERTS_HLT_PFLGS_MASK)
+#define ERTS_RBT_SET_FLAGS(T, F)					\
+    do {								\
+	ERTS_HLT_ASSERT((((UWord) (F)) & ~ERTS_HLT_PFLGS_MASK) == 0);	\
+	(T)->time.tree.parent &= ~ERTS_HLT_PFLGS_MASK;			\
+	(T)->time.tree.parent |= (F);					\
+    } while (0)
+#define ERTS_RBT_GET_PARENT(T)						\
+    ((ErtsHLTimer *) ((T)->time.tree.parent & ~ERTS_HLT_PFLGS_MASK))
+#define ERTS_RBT_SET_PARENT(T, P)					\
+    do {								\
+	ERTS_HLT_ASSERT((((UWord) (P)) & ERTS_HLT_PFLGS_MASK) == 0);	\
+	(T)->time.tree.parent &= ERTS_HLT_PFLGS_MASK;			\
+	(T)->time.tree.parent |= (UWord) (P);				\
+    } while (0)
+#define ERTS_RBT_GET_RIGHT(T) ((T)->time.tree.u.t.right)
+#define ERTS_RBT_SET_RIGHT(T, R) ((T)->time.tree.u.t.right = (R))
+#define ERTS_RBT_GET_LEFT(T) ((T)->time.tree.u.t.left)
+#define ERTS_RBT_SET_LEFT(T, L) ((T)->time.tree.u.t.left = (L))
+#define ERTS_RBT_GET_KEY(T) ((T)->timeout)
+#define ERTS_RBT_IS_LT(KX, KY) ((KX) < (KY))
+#define ERTS_RBT_IS_EQ(KX, KY) ((KX) == (KY))
+#define ERTS_RBT_WANT_DELETE
+#define ERTS_RBT_WANT_SMALLEST
+#define ERTS_RBT_WANT_LOOKUP_INSERT
+#define ERTS_RBT_WANT_REPLACE
+#ifdef ERTS_HLT_HARD_DEBUG
+#  define ERTS_RBT_WANT_FOREACH
+#  define ERTS_RBT_WANT_LOOKUP
+#endif
+#define ERTS_RBT_UNDEF
+
+#include "erl_rbtree.h"
+
+/* Use circular list for timers at same time */
+
+static ERTS_INLINE void
+same_time_list_insert(ErtsHLTimer **root, ErtsHLTimer *tmr)
+{
+    ErtsHLTimer *first = *root;
+    if (!first) {
+	ERTS_HLT_ASSERT((((UWord) root) & ERTS_HLT_PFLG_SAME_TIME) == 0);
+	tmr->time.tree.parent = ((UWord) root) | ERTS_HLT_PFLG_SAME_TIME;
+	tmr->time.tree.u.l.next = tmr;
+	tmr->time.tree.u.l.prev = tmr;
+	*root = tmr;
+    }
+    else {
+	tmr->time.tree.parent = ERTS_HLT_PFLG_SAME_TIME;
+	tmr->time.tree.u.l.next = first;
+	tmr->time.tree.u.l.prev = first->time.tree.u.l.prev;
+	first->time.tree.u.l.prev = tmr;
+	tmr->time.tree.u.l.prev->time.tree.u.l.next = tmr;
+    }
+}
+
+static ERTS_INLINE void
+same_time_list_delete(ErtsHLTimer *tmr)
+{
+    ErtsHLTimer **root, *next;
+    
+    root = (ErtsHLTimer **) (tmr->time.tree.parent & ~ERTS_HLT_PFLG_SAME_TIME);
+    next = tmr->time.tree.u.l.next;
+
+    ERTS_HLT_ASSERT((tmr->time.tree.parent
+		     == (((UWord) root) | ERTS_HLT_PFLG_SAME_TIME))
+		    || (tmr->time.tree.parent
+			== ERTS_HLT_PFLG_SAME_TIME));
+
+    if (next == tmr) {
+	ERTS_HLT_ASSERT(root && *root == tmr);
+	ERTS_HLT_ASSERT(tmr->time.tree.u.l.prev == tmr);
+	*root = NULL;
+    }
+    else {
+	if (root) {
+	    ERTS_HLT_ASSERT(*root == tmr);
+	    *root = next;
+	    next->time.tree.parent = ((UWord) root) | ERTS_HLT_PFLG_SAME_TIME;
+	}
+	tmr->time.tree.u.l.next->time.tree.u.l.prev = tmr->time.tree.u.l.prev;
+	tmr->time.tree.u.l.prev->time.tree.u.l.next = next;
+    }
+}
+
+static ERTS_INLINE void
+same_time_list_new_root(ErtsHLTimer **root)
+{
+    ErtsHLTimer *tmr = *root;
+    if (tmr) {
+	ERTS_HLT_ASSERT(root);
+	tmr->time.tree.parent = ((UWord) root) | ERTS_HLT_PFLG_SAME_TIME;
+    }
+}
+
+static ERTS_INLINE int
+same_time_list_foreach_destroy_yielding(ErtsHLTimer **root,
+					void (*op)(ErtsHLTimer *, void *),
+					void *arg,
+					ERTS_TMR_TIMEOUT_YIELD_STATE_T *ys,
+					Sint ylimit)
+{
+    Sint ycnt = ylimit;
+    ErtsHLTimer *end, *tmr = *root;
+    if (!tmr)
+	return 0;
+
+    ERTS_HLT_ASSERT(tmr->time.tree.parent
+		    == (((UWord) root) | ERTS_HLT_PFLG_SAME_TIME));
+
+    end = tmr->time.tree.u.l.prev;
+    end->time.tree.u.l.next = NULL;
+
+    while (1) {
+	ErtsHLTimer *op_tmr = tmr;
+
+	ERTS_HLT_ASSERT((tmr->time.tree.parent
+			 == (((UWord) root) | ERTS_HLT_PFLG_SAME_TIME))
+			|| (tmr->time.tree.parent
+			    == ERTS_HLT_PFLG_SAME_TIME));
+
+	tmr = tmr->time.tree.u.l.next;
+	(*op)(op_tmr, arg);
+	if (!tmr) {
+	    *root = NULL;
+	    return 0;
+	}
+	if (--ycnt <= 0) {
+	    /* Make new circle of timers left to process... */
+	    *root = tmr;
+	    end->time.tree.u.l.next = tmr;
+	    tmr->time.tree.u.l.prev = end;
+	    tmr->time.tree.parent = ((UWord) root) | ERTS_HLT_PFLG_SAME_TIME;
+	    return 1;
+	}
+    }    
+}
+
+#ifdef ERTS_HLT_HARD_DEBUG
+
+static ERTS_INLINE void
+same_time_list_foreach(ErtsHLTimer *root,
+		       void (*op)(ErtsHLTimer *, void *),
+		       void *arg)
+{
+    if (root) {
+	ErtsHLTimer *tmr = root;
+	do {
+	    (*op)(tmr, arg);
+	    tmr = tmr->time.tree.u.l.next;
+	} while (root != tmr);
+    }
+}
+
+static ERTS_INLINE ErtsHLTimer *
+same_time_list_lookup(ErtsHLTimer *root, ErtsHLTimer *x)
+{
+    if (root) {
+	ErtsHLTimer *tmr = root;
+	do {
+	    if (tmr == x)
+		return tmr;
+	    tmr = tmr->time.tree.u.l.next;
+	} while (root != tmr);
+    }
+    return NULL;
+}
+
+#endif /* ERTS_HLT_HARD_DEBUG */
+
+#define ERTS_RBT_PREFIX btm
+#define ERTS_RBT_T ErtsHLTimer
+#define ERTS_RBT_KEY_T Uint32 *
+#define ERTS_RBT_FLAGS_T UWord
+#define ERTS_RBT_INIT_EMPTY_TNODE(T)					\
+    do {								\
+	(T)->btm.tree.parent = (UWord) NULL;				\
+	(T)->btm.tree.right = NULL;					\
+	(T)->btm.tree.left = NULL;					\
+    } while (0)
+#define ERTS_RBT_IS_RED(T)						\
+    ((int) ((T)->btm.tree.parent & ERTS_HLT_PFLG_RED))
+#define ERTS_RBT_SET_RED(T)						\
+    ((T)->btm.tree.parent |= ERTS_HLT_PFLG_RED)
+#define ERTS_RBT_IS_BLACK(T)						\
+    (!ERTS_RBT_IS_RED((T)))
+#define ERTS_RBT_SET_BLACK(T)						\
+    ((T)->btm.tree.parent &= ~ERTS_HLT_PFLG_RED)
+#define ERTS_RBT_GET_FLAGS(T)						\
+    ((T)->btm.tree.parent & ERTS_HLT_PFLGS_MASK)
+#define ERTS_RBT_SET_FLAGS(T, F)					\
+    do {								\
+	ERTS_HLT_ASSERT((((UWord) (F)) & ~ERTS_HLT_PFLGS_MASK) == 0);	\
+	(T)->btm.tree.parent &= ~ERTS_HLT_PFLGS_MASK;			\
+	(T)->btm.tree.parent |= (F);					\
+    } while (0)
+#define ERTS_RBT_GET_PARENT(T)						\
+    ((ErtsHLTimer *) ((T)->btm.tree.parent & ~ERTS_HLT_PFLGS_MASK))
+#define ERTS_RBT_SET_PARENT(T, P)					\
+    do {								\
+	ERTS_HLT_ASSERT((((UWord) (P)) & ERTS_HLT_PFLGS_MASK) == 0);	\
+	(T)->btm.tree.parent &= ERTS_HLT_PFLGS_MASK;			\
+	(T)->btm.tree.parent |= (UWord) (P);				\
+    } while (0)
+#define ERTS_RBT_GET_RIGHT(T) ((T)->btm.tree.right)
+#define ERTS_RBT_SET_RIGHT(T, R) ((T)->btm.tree.right = (R))
+#define ERTS_RBT_GET_LEFT(T) ((T)->btm.tree.left)
+#define ERTS_RBT_SET_LEFT(T, L) ((T)->btm.tree.left = (L))
+#define ERTS_RBT_GET_KEY(T) ((T)->btm.refn)
+#define ERTS_RBT_IS_LT(KX, KY) refn_is_lt((KX), (KY))
+#define ERTS_RBT_IS_EQ(KX, KY) \
+    (((KX)[0] == (KY)[0]) & ((KX)[1] == (KY)[1]) & ((KX)[2] == (KY)[2]))
+#define ERTS_RBT_WANT_DELETE
+#define ERTS_RBT_WANT_INSERT
+#define ERTS_RBT_WANT_LOOKUP
+#define ERTS_RBT_WANT_FOREACH
+#define ERTS_RBT_UNDEF
+
+#include "erl_rbtree.h"
+
+#define ERTS_RBT_PREFIX proc_btm
+#define ERTS_RBT_T ErtsHLTimer
+#define ERTS_RBT_KEY_T Uint32 *
+#define ERTS_RBT_FLAGS_T UWord
+#define ERTS_RBT_INIT_EMPTY_TNODE(T)					\
+    do {								\
+	(T)->btm.proc_tree.parent = (UWord) NULL;			\
+	(T)->btm.proc_tree.right = NULL;				\
+	(T)->btm.proc_tree.left = NULL;					\
+    } while (0)
+#define ERTS_RBT_IS_RED(T)						\
+    ((int) ((T)->btm.proc_tree.parent & ERTS_HLT_PFLG_RED))
+#define ERTS_RBT_SET_RED(T)						\
+    ((T)->btm.proc_tree.parent |= ERTS_HLT_PFLG_RED)
+#define ERTS_RBT_IS_BLACK(T)						\
+    (!ERTS_RBT_IS_RED((T)))
+#define ERTS_RBT_SET_BLACK(T)						\
+    ((T)->btm.proc_tree.parent &= ~ERTS_HLT_PFLG_RED)
+#define ERTS_RBT_GET_FLAGS(T)						\
+    ((T)->btm.proc_tree.parent & ERTS_HLT_PFLGS_MASK)
+#define ERTS_RBT_SET_FLAGS(T, F)					\
+    do {								\
+	ERTS_HLT_ASSERT((((UWord) (F)) & ~ERTS_HLT_PFLGS_MASK) == 0);	\
+	(T)->btm.proc_tree.parent &= ~ERTS_HLT_PFLGS_MASK;		\
+	(T)->btm.proc_tree.parent |= (F);				\
+    } while (0)
+#define ERTS_RBT_GET_PARENT(T)						\
+    ((ErtsHLTimer *) ((T)->btm.proc_tree.parent & ~ERTS_HLT_PFLGS_MASK))
+#define ERTS_RBT_SET_PARENT(T, P)					\
+    do {								\
+	ERTS_HLT_ASSERT((((UWord) (P)) & ERTS_HLT_PFLGS_MASK) == 0);	\
+	(T)->btm.proc_tree.parent &= ERTS_HLT_PFLGS_MASK;		\
+	(T)->btm.proc_tree.parent |= (UWord) (P);			\
+    } while (0)
+#define ERTS_RBT_GET_RIGHT(T) ((T)->btm.proc_tree.right)
+#define ERTS_RBT_SET_RIGHT(T, R) ((T)->btm.proc_tree.right = (R))
+#define ERTS_RBT_GET_LEFT(T) ((T)->btm.proc_tree.left)
+#define ERTS_RBT_SET_LEFT(T, L) ((T)->btm.proc_tree.left = (L))
+#define ERTS_RBT_GET_KEY(T) ((T)->btm.refn)
+#define ERTS_RBT_IS_LT(KX, KY) refn_is_lt((KX), (KY))
+#define ERTS_RBT_IS_EQ(KX, KY) \
+    (((KX)[0] == (KY)[0]) & ((KX)[1] == (KY)[1]) & ((KX)[2] == (KY)[2]))
+#define ERTS_RBT_WANT_DELETE
+#define ERTS_RBT_WANT_INSERT
+#define ERTS_RBT_WANT_LOOKUP
+#define ERTS_RBT_WANT_FOREACH_DESTROY_YIELDING
+#define ERTS_RBT_UNDEF
+
+#include "erl_rbtree.h"
+
+#define ERTS_RBT_PREFIX abtm
+#define ERTS_RBT_T ErtsHLTimer
+#define ERTS_RBT_KEY_T Uint32 *
+#define ERTS_RBT_FLAGS_T UWord
+#define ERTS_RBT_INIT_EMPTY_TNODE(T)					\
+    do {								\
+	(T)->abtm.tree.parent = (UWord) NULL;				\
+	(T)->abtm.tree.right = NULL;					\
+	(T)->abtm.tree.left = NULL;					\
+    } while (0)
+#define ERTS_RBT_IS_RED(T)						\
+    ((int) ((T)->abtm.tree.parent & ERTS_HLT_PFLG_RED))
+#define ERTS_RBT_SET_RED(T)						\
+    ((T)->abtm.tree.parent |= ERTS_HLT_PFLG_RED)
+#define ERTS_RBT_IS_BLACK(T)						\
+    (!ERTS_RBT_IS_RED((T)))
+#define ERTS_RBT_SET_BLACK(T)						\
+    ((T)->abtm.tree.parent &= ~ERTS_HLT_PFLG_RED)
+#define ERTS_RBT_GET_FLAGS(T)						\
+    ((T)->abtm.tree.parent & ERTS_HLT_PFLGS_MASK)
+#define ERTS_RBT_SET_FLAGS(T, F)					\
+    do {								\
+	ERTS_HLT_ASSERT((((UWord) (F)) & ~ERTS_HLT_PFLGS_MASK) == 0);	\
+	(T)->abtm.tree.parent &= ~ERTS_HLT_PFLGS_MASK;			\
+	(T)->abtm.tree.parent |= (F);					\
+    } while (0)
+#define ERTS_RBT_GET_PARENT(T)						\
+    ((ErtsHLTimer *) ((T)->abtm.tree.parent & ~ERTS_HLT_PFLGS_MASK))
+#define ERTS_RBT_SET_PARENT(T, P)					\
+    do {								\
+	ERTS_HLT_ASSERT((((UWord) (P)) & ERTS_HLT_PFLGS_MASK) == 0);	\
+	(T)->abtm.tree.parent &= ERTS_HLT_PFLGS_MASK;			\
+	(T)->abtm.tree.parent |= (UWord) (P);				\
+    } while (0)
+#define ERTS_RBT_GET_RIGHT(T) ((T)->abtm.tree.right)
+#define ERTS_RBT_SET_RIGHT(T, R) ((T)->abtm.tree.right = (R))
+#define ERTS_RBT_GET_LEFT(T) ((T)->abtm.tree.left)
+#define ERTS_RBT_SET_LEFT(T, L) ((T)->abtm.tree.left = (L))
+#define ERTS_RBT_GET_KEY(T) ((T)->btm.refn)
+#define ERTS_RBT_IS_LT(KX, KY) refn_is_lt((KX), (KY))
+#define ERTS_RBT_IS_EQ(KX, KY) \
+    (((KX)[0] == (KY)[0]) & ((KX)[1] == (KY)[1]) & ((KX)[2] == (KY)[2]))
+#define ERTS_RBT_WANT_DELETE
+#define ERTS_RBT_WANT_INSERT
+#define ERTS_RBT_WANT_LOOKUP
+#define ERTS_RBT_WANT_FOREACH_DESTROY_YIELDING
+#define ERTS_RBT_UNDEF
+
+#include "erl_rbtree.h"
+
+#ifdef ERTS_SMP
+static void init_canceled_queue(ErtsHLTCncldTmrQ *cq);
+#endif
+
+void
+erts_hl_timer_init(void)
+{
+    init_tw_timer_alloc();
+    init_bif_timer_pre_alloc();
+}
+
+ErtsHLTimerService *
+erts_create_timer_service(void)
+{
+    ErtsYieldingTimeoutState init_yield = ERTS_TMR_YIELDING_TIMEOUT_STATE_INITER;
+    ErtsHLTimerService *srv;
+
+    srv = erts_alloc_permanent_cache_aligned(ERTS_ALC_T_TIMER_SERVICE,
+					     sizeof(ErtsHLTimerService));
+    srv->time_tree = NULL;
+    srv->btm_tree = NULL;
+    srv->next_timeout = NULL;
+    srv->yield = init_yield;
+    erts_twheel_init_timer(&srv->service_timer);
+
+#ifdef ERTS_SMP
+    init_canceled_queue(&srv->canceled_queue);
+#endif
+
+    return srv;
+}
+
+size_t
+erts_timer_type_size(ErtsAlcType_t type)
+{
+    switch (type) {
+    case ERTS_ALC_T_LL_PTIMER: return sizeof(ErtsTWTimer);
+    case ERTS_ALC_T_HL_PTIMER: return ERTS_HL_PTIMER_SIZE;
+    case ERTS_ALC_T_BIF_TIMER: return ERTS_BIF_TIMER_SIZE;
+    case ERTS_ALC_T_ABIF_TIMER: return ERTS_ABIF_TIMER_SIZE;
+    default: ERTS_INTERNAL_ERROR("Unknown type");
+    }
+    return 0;
+}
+
+static ERTS_INLINE ErtsMonotonicTime
+get_timeout_pos(ErtsMonotonicTime now, ErtsMonotonicTime msec)
+{
+    ErtsMonotonicTime timeout_pos;
+    if (msec <= 0)
+	return ERTS_MONOTONIC_TO_CLKTCKS(now);
+    timeout_pos = ERTS_MONOTONIC_TO_CLKTCKS(now-1);
+    timeout_pos += ERTS_MSEC_TO_CLKTCKS(msec) + 1;
+    return timeout_pos;
+}
+
+static ERTS_INLINE Sint64
+get_time_left(ErtsSchedulerData *esdp, ErtsMonotonicTime timeout_pos)
+{
+    ErtsMonotonicTime now = erts_get_monotonic_time(esdp);
+
+    now = ERTS_MONOTONIC_TO_CLKTCKS(now-1)+1;
+    if (timeout_pos <= now)
+	return (Sint64) 0;
+    return (Sint64) ERTS_CLKTCKS_TO_MSEC(timeout_pos - now);
+}
+
+static ERTS_INLINE int
+proc_timeout_common(Process *proc, void *tmr)
+{
+    if (tmr == (void *) erts_smp_atomic_cmpxchg_mb(&proc->common.timer,
+						   ERTS_PTMR_TIMEDOUT,
+						   (erts_aint_t) tmr)) {
+	erts_aint32_t state = erts_smp_atomic32_read_acqb(&proc->state);
+	if (!(state & (ERTS_PSFLG_ACTIVE|ERTS_PSFLG_EXITING)))
+	    erts_schedule_process(proc, state, 0);
+	return 1;
+    }
+    return 0;
+}
+
+static ERTS_INLINE int
+port_timeout_common(Port *port, void *tmr)
+{
+    if (tmr == (void *) erts_smp_atomic_cmpxchg_mb(&port->common.timer,
+						   ERTS_PTMR_TIMEDOUT,
+						   (erts_aint_t) tmr)) {
+	erts_port_task_schedule(port->common.id,
+				&port->timeout_task,
+				ERTS_PORT_TASK_TIMEOUT);
+	return 1;
+    }
+    return 0;
+}
+
+/*
+ * Basic timer wheel timer stuff
+ */
+
+static void
+scheduled_tw_timer_destroy(void *vtmr)
+{
+    tw_timer_free((ErtsTWTimer *) vtmr);
+}
+
+static void
+schedule_tw_timer_destroy(ErtsTWTimer *tmr)
+{
+    /*
+     * Reference to process/port can be
+     * dropped at once...
+     */
+    if (tmr->head.roflgs & ERTS_TMR_ROFLG_PROC)
+	erts_proc_dec_refc((Process *) tmr->p);
+    else
+	erts_port_dec_refc((Port *) tmr->p);
+
+    erts_schedule_thr_prgr_later_cleanup_op(
+	scheduled_tw_timer_destroy,
+	(void *) tmr,
+	&tmr->tw_tmr.u.cleanup,
+	sizeof(ErtsTWTimer));
+}
+
+static ERTS_INLINE void
+tw_timer_dec_refc(ErtsTWTimer *tmr)
+{
+    if (erts_smp_atomic32_dec_read_relb(&tmr->head.refc) == 0) {
+	ERTS_HLT_SMP_MEMBAR_LoadLoad_LoadStore;
+	schedule_tw_timer_destroy(tmr);
+    }
+}
+
+static void
+tw_proc_timeout(void *vtwtp)
+{
+    ErtsTWTimer *twtp = (ErtsTWTimer *) vtwtp;
+    Process *proc = (Process *) twtp->p;
+    if (proc_timeout_common(proc, vtwtp))
+	tw_timer_dec_refc(twtp);
+    tw_timer_dec_refc(twtp);
+}
+
+static void
+tw_port_timeout(void *vtwtp)
+{
+    ErtsTWTimer *twtp = (ErtsTWTimer *) vtwtp;
+    Port *port = (Port *) twtp->p;
+    if (port_timeout_common(port, vtwtp))
+	tw_timer_dec_refc(twtp);
+    tw_timer_dec_refc(twtp);
+}
+
+static void
+tw_ptimer_cancel(void *vtwtp)
+{
+    tw_timer_dec_refc((ErtsTWTimer *) vtwtp);    
+}
+
+static void
+cancel_tw_timer(ErtsSchedulerData *esdp, ErtsTWTimer *tmr)
+{
+    ERTS_HLT_ASSERT((tmr->head.roflgs & ERTS_TMR_ROFLG_SID_MASK)
+		    == (Uint32) esdp->no);
+    erts_twheel_cancel_timer(esdp->timer_wheel, &tmr->tw_tmr);
+}
+
+static ErtsTWTimer *
+create_tw_timer(ErtsSchedulerData *esdp, 
+		void *p, int is_proc,
+		ErtsMonotonicTime timeout_pos)
+{
+    ErtsTWTimer *tmr;
+    void (*timeout_func)(void *);
+
+    tmr = tw_timer_alloc();
+    erts_twheel_init_timer(&tmr->tw_tmr);
+
+    tmr->head.roflgs = (Uint32) esdp->no;
+    ERTS_HLT_ASSERT((tmr->head.roflgs
+		     & ~ERTS_TMR_ROFLG_SID_MASK) == 0);
+    tmr->p = p;
+    if (is_proc) {
+	tmr->head.roflgs |= ERTS_TMR_ROFLG_PROC;
+	timeout_func = tw_proc_timeout;
+	erts_proc_inc_refc((Process *) p);
+    }
+    else {
+	tmr->head.roflgs |= ERTS_TMR_ROFLG_PORT;
+	timeout_func = tw_port_timeout;
+	erts_port_inc_refc((Port *) p);
+    }
+
+    erts_smp_atomic32_init_nob(&tmr->head.refc, 2);
+
+    erts_twheel_set_timer(esdp->timer_wheel,
+			  &tmr->tw_tmr,
+			  timeout_func,
+			  tw_ptimer_cancel,
+			  tmr,
+			  timeout_pos);
+
+    return tmr;
+}
+
+/*
+ * Basic high level timer stuff
+ */
+
+static ERTS_INLINE void
+hl_timer_destroy(ErtsHLTimer *tmr)
+{
+    Uint32 roflgs = tmr->head.roflgs;
+    if (!(roflgs & ERTS_TMR_ROFLG_BIF_TMR))
+	erts_free(ERTS_ALC_T_HL_PTIMER, tmr);
+    else {
+	if (tmr->btm.bp)
+	    free_message_buffer(tmr->btm.bp);
+	if (roflgs & ERTS_TMR_ROFLG_PRE_ALC)
+	    bif_timer_pre_free(tmr);
+	else if (roflgs & ERTS_TMR_ROFLG_ABIF_TMR)
+	    erts_free(ERTS_ALC_T_ABIF_TIMER, tmr);
+	else
+	    erts_free(ERTS_ALC_T_BIF_TIMER, tmr);
+    }
+}
+
+static void
+scheduled_hl_timer_destroy(void *vtmr)
+{
+    hl_timer_destroy((ErtsHLTimer *) vtmr);
+}
+
+static void
+schedule_hl_timer_destroy(ErtsHLTimer *tmr, Uint32 roflgs)
+{
+    UWord size;
+
+    /*
+     * Reference to process/port can be dropped
+     * at once...
+     */
+
+    ERTS_HLT_ASSERT(erts_smp_atomic32_read_nob(&tmr->head.refc) == 0);
+
+    if (roflgs & ERTS_TMR_ROFLG_REG_NAME) {
+	ERTS_HLT_ASSERT(is_atom(tmr->receiver.name));
+    }
+    else if (roflgs & ERTS_TMR_ROFLG_PROC) {
+	ERTS_HLT_ASSERT(tmr->receiver.proc);
+	erts_proc_dec_refc(tmr->receiver.proc);
+    }
+    else if (roflgs & ERTS_TMR_ROFLG_PORT) {
+	ERTS_HLT_ASSERT(tmr->receiver.port);
+	erts_port_dec_refc(tmr->receiver.port);
+    }
+
+    if (!(roflgs & ERTS_TMR_ROFLG_BIF_TMR))
+	size = ERTS_HL_PTIMER_SIZE;
+    else {
+	/*
+	 * Message buffer can be dropped at
+	 * once...
+	 */
+	if (tmr->btm.bp) {
+	    free_message_buffer(tmr->btm.bp);
+	    tmr->btm.bp = NULL;
+	}
+	size = sizeof(ErtsHLTimer);
+    }
+
+    erts_schedule_thr_prgr_later_cleanup_op(
+	scheduled_hl_timer_destroy, tmr,
+	&tmr->time.cleanup, size);
+}
+
+static ERTS_INLINE void
+hl_timer_pre_dec_refc(ErtsHLTimer *tmr)
+{
+#ifdef ERTS_HLT_DEBUG
+    erts_aint_t refc;
+    refc = erts_smp_atomic32_dec_read_nob(&tmr->head.refc);
+    ERTS_HLT_ASSERT(refc > 0);
+#else
+    erts_smp_atomic32_dec_nob(&tmr->head.refc);
+#endif
+}
+
+static ERTS_INLINE void
+hl_timer_dec_refc(ErtsHLTimer *tmr, Uint32 roflgs)
+{
+    if (erts_smp_atomic32_dec_read_relb(&tmr->head.refc) == 0) {
+	ERTS_HLT_SMP_MEMBAR_LoadLoad_LoadStore;
+	schedule_hl_timer_destroy(tmr, roflgs);
+    }
+}
+
+static void hlt_service_timeout(void *vesdp);
+#ifdef ERTS_SMP
+static void handle_canceled_queue(ErtsSchedulerData *esdp,
+				  ErtsHLTCncldTmrQ *cq,
+				  int use_limit,
+				  int ops_limit,
+				  int *need_thr_progress,
+				  ErtsThrPrgrVal *thr_prgr_p,
+				  int *need_more_work);
+#endif
+
+static ERTS_INLINE void
+check_canceled_queue(ErtsSchedulerData *esdp, ErtsHLTimerService *srv)
+{
+#if defined(ERTS_SMP) && ERTS_TMR_CHECK_CANCEL_ON_CREATE
+    ErtsHLTCncldTmrQ *cq = &srv->canceled_queue;
+    if (cq->head.first != cq->head.unref_end)
+	handle_canceled_queue(esdp, cq, 1,
+			      ERTS_TMR_CANCELED_TIMER_SMALL_LIMIT,
+			      NULL, NULL, NULL);
+#endif
+}
+
+static void
+hlt_delete_abtm(ErtsHLTimer *tmr)
+{
+    Process *proc;
+
+    ERTS_HLT_ASSERT(tmr->head.roflgs & ERTS_TMR_ROFLG_ABIF_TMR);
+
+    proc = erts_proc_lookup(tmr->abtm.accessor);
+
+    if (proc) {
+	int deref = 0;
+	erts_smp_proc_lock(proc, ERTS_PROC_LOCK_BTM);
+	if (tmr->abtm.tree.parent != ERTS_HLT_PFIELD_NOT_IN_TABLE) {
+	    abtm_rbt_delete(&proc->accessor_bif_timers, tmr);
+	    deref = 1;
+	    tmr->abtm.tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+	}
+	erts_smp_proc_unlock(proc, ERTS_PROC_LOCK_BTM);
+	if (deref)
+	    hl_timer_pre_dec_refc(tmr);
+    }
+}
+
+static ErtsHLTimer *
+create_hl_timer(ErtsSchedulerData *esdp,
+		ErtsMonotonicTime timeout_pos,
+		int short_time, int is_bif_tmr,
+		void *rcvrp, Eterm rcvr, Eterm acsr,
+		Eterm msg, Uint32 *refn)
+{
+    ErtsHLTimerService *srv = esdp->timer_service;
+    ErtsHLTimer *tmr, *st_tmr;
+    erts_aint32_t refc;
+    Uint32 roflgs;
+    int is_abif_tmr = is_bif_tmr && is_value(acsr) && acsr != rcvr;
+
+    check_canceled_queue(esdp, srv);
+
+    ERTS_HLT_ASSERT((esdp->no & ~ERTS_TMR_ROFLG_SID_MASK) == 0);
+
+    roflgs = ((Uint32) esdp->no) | ERTS_TMR_ROFLG_HLT;
+
+    if (!is_bif_tmr)
+	tmr = erts_alloc(ERTS_ALC_T_HL_PTIMER,
+			 ERTS_HL_PTIMER_SIZE);
+    else if (short_time) {
+	tmr = bif_timer_pre_alloc();
+	if (!tmr)
+	    goto alloc_bif_timer;
+	roflgs |= ERTS_TMR_ROFLG_PRE_ALC;
+    }
+    else {
+    alloc_bif_timer:
+	if (is_abif_tmr)
+	    tmr = erts_alloc(ERTS_ALC_T_ABIF_TIMER,
+			     ERTS_ABIF_TIMER_SIZE);
+	else
+	    tmr = erts_alloc(ERTS_ALC_T_BIF_TIMER,
+			     ERTS_BIF_TIMER_SIZE);
+    }
+
+    tmr->timeout = timeout_pos;
+
+    if (!is_bif_tmr) {
+	if (is_internal_pid(rcvr)) {
+	    erts_proc_inc_refc((Process *) rcvrp);
+	    tmr->receiver.proc = (Process *) rcvrp;
+	    roflgs |= ERTS_TMR_ROFLG_PROC;
+	}
+	else {
+	    erts_port_inc_refc((Port *) rcvrp);
+	    ERTS_HLT_ASSERT(is_internal_port(rcvr));
+	    tmr->receiver.port = (Port *) rcvrp;
+	    roflgs |= ERTS_TMR_ROFLG_PORT;
+	}
+	refc = 2;
+    }
+    else {
+	Uint hsz;
+
+	roflgs |= ERTS_TMR_ROFLG_BIF_TMR;
+	if (is_internal_pid(rcvr)) {
+	    roflgs |= ERTS_TMR_ROFLG_PROC;
+	    tmr->receiver.proc = (Process *) rcvrp;
+	    refc = 2;
+	}
+	else {
+	    ERTS_HLT_ASSERT(is_atom(rcvr));
+	    roflgs |= ERTS_TMR_ROFLG_REG_NAME;
+	    tmr->receiver.name = rcvr;
+	    refc = 1;
+	}
+
+	hsz = is_immed(msg) ? ((Uint) 0) : size_object(msg);
+	if (!hsz) {
+	    tmr->btm.message = msg;
+	    tmr->btm.bp = NULL;
+	}
+	else {
+	    ErlHeapFragment *bp = new_message_buffer(hsz);
+	    Eterm *hp = bp->mem;
+	    tmr->btm.message = copy_struct(msg, hsz, &hp, &bp->off_heap);
+	    tmr->btm.bp = bp;
+	}
+	tmr->btm.refn[0] = refn[0];
+	tmr->btm.refn[1] = refn[1];
+	tmr->btm.refn[2] = refn[2];
+
+	tmr->btm.proc_tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+	if (is_abif_tmr) {
+	    Process *aproc;
+	    roflgs |= ERTS_TMR_ROFLG_ABIF_TMR;
+	    tmr->abtm.accessor = acsr;
+	    aproc = erts_proc_lookup(acsr);
+	    if (!aproc)
+		tmr->abtm.tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+	    else {
+		refc++;
+		erts_smp_proc_lock(aproc, ERTS_PROC_LOCK_BTM);
+		abtm_rbt_insert(&aproc->accessor_bif_timers, tmr);
+		erts_smp_proc_unlock(aproc, ERTS_PROC_LOCK_BTM);
+	    }
+	}
+    }
+
+    tmr->head.roflgs = roflgs;
+    erts_smp_atomic32_init_nob(&tmr->head.refc, refc);
+    erts_smp_atomic32_init_nob(&tmr->state, ERTS_TMR_STATE_ACTIVE);
+
+    ERTS_HLT_HDBG_CHK_SRV(srv);
+
+    if (!srv->next_timeout
+	|| tmr->timeout < srv->next_timeout->timeout) {
+	if (srv->next_timeout)
+	    erts_twheel_cancel_timer(esdp->timer_wheel,
+				     &srv->service_timer);
+	erts_twheel_set_timer(esdp->timer_wheel,
+			      &srv->service_timer,
+			      hlt_service_timeout,
+			      NULL,
+			      (void *) esdp,
+			      tmr->timeout);
+	srv->next_timeout = tmr;
+    }
+
+    st_tmr = time_rbt_lookup_insert(&srv->time_tree, tmr);
+    tmr->time.tree.same_time = st_tmr;
+    if (st_tmr)
+	same_time_list_insert(&st_tmr->time.tree.same_time, tmr);
+
+    if (is_bif_tmr)
+	btm_rbt_insert(&srv->btm_tree, tmr);
+
+#ifdef ERTS_HLT_HARD_DEBUG
+    tmr->pending_timeout = 0;
+#endif
+
+    ERTS_HLT_HDBG_CHK_SRV(srv);
+
+    return tmr;
+}
+
+static ERTS_INLINE void
+hlt_bif_timer_timeout(ErtsHLTimer *tmr, Uint32 roflgs)
+{
+    ErtsProcLocks proc_locks = ERTS_PROC_LOCKS_MSG_SEND;
+    Process *proc;
+    int dec_refc = 0;
+    Uint32 is_reg_name = (roflgs & ERTS_TMR_ROFLG_REG_NAME);
+    ERTS_HLT_ASSERT(roflgs & ERTS_TMR_ROFLG_BIF_TMR);
+
+    if (tmr->head.roflgs & ERTS_TMR_ROFLG_ABIF_TMR)
+	hlt_delete_abtm(tmr);
+
+    if (is_reg_name) {
+	Eterm pid;
+	ERTS_HLT_ASSERT(is_atom(tmr->receiver.name));
+	pid = erts_whereis_name_to_id(NULL, tmr->receiver.name);
+	proc = erts_proc_lookup(pid);
+    }
+    else {
+	ERTS_HLT_ASSERT(roflgs & ERTS_TMR_ROFLG_PROC);
+	ERTS_HLT_ASSERT(tmr->receiver.proc);
+
+	proc = tmr->receiver.proc;
+	proc_locks |= ERTS_PROC_LOCK_BTM;
+    }
+    if (proc) {
+	erts_smp_proc_lock(proc, proc_locks);
+	/*
+	 * If process is exiting, let it clean up
+	 * the btm tree by itself (it may be in
+	 * the middle of tree destruction).
+	 */
+	if (!ERTS_PROC_IS_EXITING(proc)) {
+	    erts_queue_message(proc,
+			       &proc_locks,
+			       tmr->btm.bp,
+			       tmr->btm.message,
+			       NIL
+#ifdef USE_VM_PROBES
+			       , NIL
+#endif
+		);
+	    erts_smp_proc_unlock(proc, ERTS_PROC_LOCKS_MSG_SEND);
+	    proc_locks &= ~ERTS_PROC_LOCKS_MSG_SEND;
+	    tmr->btm.bp = NULL;
+	    if (tmr->btm.proc_tree.parent != ERTS_HLT_PFIELD_NOT_IN_TABLE) {
+		proc_btm_rbt_delete(&proc->bif_timers, tmr);
+		tmr->btm.proc_tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+		dec_refc = 1;
+	    }
+	}
+	if (proc_locks)
+	    erts_smp_proc_unlock(proc, proc_locks);
+	if (dec_refc)
+	    hl_timer_pre_dec_refc(tmr);
+    }
+}
+
+static ERTS_INLINE void
+hlt_proc_timeout(ErtsHLTimer *tmr)
+{
+    if (proc_timeout_common(tmr->receiver.proc, (void *) tmr))
+	hl_timer_dec_refc(tmr, tmr->head.roflgs);
+}
+
+static ERTS_INLINE void
+hlt_port_timeout(ErtsHLTimer *tmr)
+{
+    if (port_timeout_common(tmr->receiver.port, (void *) tmr))
+	hl_timer_dec_refc(tmr, tmr->head.roflgs);
+}
+
+static void hlt_timeout(ErtsHLTimer *tmr, void *vsrv)
+{
+    ErtsHLTimerService *srv = (ErtsHLTimerService *) vsrv;
+    Uint32 roflgs;
+    erts_aint32_t state;
+
+    ERTS_HLT_HDBG_CHK_SRV(srv);
+
+    roflgs = tmr->head.roflgs;
+    ERTS_HLT_ASSERT(roflgs & ERTS_TMR_ROFLG_HLT);
+
+    state = erts_smp_atomic32_cmpxchg_acqb(&tmr->state,
+					   ERTS_TMR_STATE_TIMED_OUT,
+					   ERTS_TMR_STATE_ACTIVE);
+
+    ERTS_HLT_ASSERT(state == ERTS_TMR_STATE_CANCELED
+		    || state == ERTS_TMR_STATE_ACTIVE);
+
+    if (state == ERTS_TMR_STATE_ACTIVE) {
+
+	if (roflgs & ERTS_TMR_ROFLG_BIF_TMR)
+	    hlt_bif_timer_timeout(tmr, roflgs);
+	else if (roflgs & ERTS_TMR_ROFLG_PROC)
+	    hlt_proc_timeout(tmr);
+	else {
+	    ERTS_HLT_ASSERT(roflgs & ERTS_TMR_ROFLG_PORT);
+	    hlt_port_timeout(tmr);
+	}
+    }
+
+    tmr->time.tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+    if ((roflgs & ERTS_TMR_ROFLG_BIF_TMR)
+	&& tmr->btm.tree.parent != ERTS_HLT_PFIELD_NOT_IN_TABLE) {
+	btm_rbt_delete(&srv->btm_tree, tmr);
+	tmr->btm.tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+    }
+
+    ERTS_HLT_HDBG_CHK_SRV(srv);
+
+    hl_timer_dec_refc(tmr, roflgs);
+}
+
+#ifdef ERTS_HLT_HARD_DEBUG
+static void
+set_pending_timeout(ErtsHLTimer *tmr, void *unused)
+{
+    tmr->pending_timeout = -1;
+}
+#endif
+
+static void
+hlt_service_timeout(void *vesdp)
+{
+    ErtsSchedulerData *esdp = (ErtsSchedulerData *) vesdp;
+    ErtsHLTimerService *srv = esdp->timer_service;
+    ErtsHLTimer *tmr = srv->next_timeout;
+    int yield;
+
+    ERTS_HLT_HDBG_CHK_SRV(srv);
+
+    ERTS_HLT_ASSERT(esdp == erts_get_scheduler_data());
+
+    ERTS_HLT_ASSERT(!srv->yield.root || srv->yield.root == tmr);
+    ERTS_HLT_ASSERT(tmr);
+    ERTS_HLT_ASSERT(tmr->timeout <= erts_get_monotonic_time(esdp));
+
+    if (!srv->yield.root) {
+	ERTS_HLT_ASSERT(tmr->time.tree.parent
+			!= ERTS_HLT_PFIELD_NOT_IN_TABLE);
+	time_rbt_delete(&srv->time_tree, tmr);
+	tmr->time.tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+#ifdef ERTS_HLT_HARD_DEBUG
+	tmr->pending_timeout = 1;
+	if (tmr->time.tree.same_time)
+	    same_time_list_foreach(tmr->time.tree.same_time, set_pending_timeout, NULL);
+#endif
+    }
+
+    if (!tmr->time.tree.same_time && !srv->yield.root)
+	yield = 0;
+    else {
+	yield = same_time_list_foreach_destroy_yielding(
+	    &tmr->time.tree.same_time, hlt_timeout, (void *) srv,
+	    &srv->yield.state, ERTS_TMR_TIMEOUT_YIELD_LIMIT);
+    }
+
+    if (yield)
+	srv->yield.root = tmr;
+    else {
+	srv->yield.root = NULL;
+	hlt_timeout(tmr, (void *) srv);
+
+	tmr = time_rbt_smallest(srv->time_tree);
+	srv->next_timeout = tmr;
+    }
+
+    ERTS_HLT_HDBG_CHK_SRV(srv);
+
+    if (tmr)
+	erts_twheel_set_timer(esdp->timer_wheel,
+			      &srv->service_timer,
+			      hlt_service_timeout,
+			      NULL,
+			      vesdp,
+			      tmr->timeout);
+}
+
+static void
+hlt_delete_timer(ErtsSchedulerData *esdp, ErtsHLTimer *tmr)
+{
+    ErtsHLTimerService *srv = esdp->timer_service;
+
+    ERTS_HLT_HDBG_CHK_SRV(srv);
+
+    if (tmr->head.roflgs & ERTS_TMR_ROFLG_BIF_TMR) {
+
+	if (tmr->btm.tree.parent != ERTS_HLT_PFIELD_NOT_IN_TABLE) {
+	    btm_rbt_delete(&srv->btm_tree, tmr);
+	    tmr->btm.tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+	}
+
+	if (tmr->head.roflgs & ERTS_TMR_ROFLG_ABIF_TMR)
+	    hlt_delete_abtm(tmr);
+    }
+
+    if (tmr->time.tree.parent == ERTS_HLT_PFIELD_NOT_IN_TABLE) {
+	/* Already removed... */
+	ERTS_HLT_HDBG_CHK_SRV(srv);
+	return;
+    }
+
+    if (tmr->time.tree.parent & ERTS_HLT_PFLG_SAME_TIME) {
+	same_time_list_delete(tmr);
+    }
+    else if (tmr->time.tree.same_time) {
+	ErtsHLTimer *st_container;
+
+	ERTS_HLT_ASSERT((tmr->time.tree.parent & ERTS_HLT_PFLG_SAME_TIME) == 0);
+	st_container = tmr->time.tree.same_time->time.tree.u.l.prev;
+
+	ERTS_HLT_ASSERT(st_container);
+	ERTS_HLT_ASSERT(st_container->time.tree.parent
+			 & ERTS_HLT_PFLG_SAME_TIME);
+	ERTS_HLT_ASSERT(tmr->timeout == st_container->timeout);
+
+	same_time_list_delete(st_container);
+	st_container->time.tree.same_time = tmr->time.tree.same_time;
+	same_time_list_new_root(&st_container->time.tree.same_time);
+
+	time_rbt_replace(&srv->time_tree, tmr, st_container);
+	ERTS_HLT_ASSERT((st_container->time.tree.parent
+			 & ERTS_HLT_PFLG_SAME_TIME) == 0);
+
+	if (srv->next_timeout == tmr)
+	    srv->next_timeout = st_container;
+    }
+    else {
+	ERTS_HLT_ASSERT((tmr->time.tree.parent & ERTS_HLT_PFLG_SAME_TIME) == 0);
+	time_rbt_delete(&srv->time_tree, tmr);
+	if (tmr == srv->next_timeout) {
+	    ErtsHLTimer *smlst;
+	    erts_twheel_cancel_timer(esdp->timer_wheel,
+				     &srv->service_timer);
+	    smlst = time_rbt_smallest(srv->time_tree);
+	    srv->next_timeout = smlst;
+	    if (smlst) {
+		ERTS_HLT_ASSERT(smlst->timeout > tmr->timeout);
+		erts_twheel_set_timer(esdp->timer_wheel,
+				      &srv->service_timer,
+				      hlt_service_timeout,
+				      NULL,
+				      (void *) esdp,
+				      smlst->timeout);
+	    }
+	}
+    }
+    tmr->time.tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+
+    hl_timer_dec_refc(tmr, tmr->head.roflgs);
+
+    ERTS_HLT_HDBG_CHK_SRV(srv);
+}
+
+/*
+ * Pass canceled timers back to originating scheduler
+ */
+
+static ERTS_INLINE void
+cleanup_sched_local_canceled_timer(ErtsSchedulerData *esdp,
+				   ErtsTimer *tmr)
+{
+    Uint32 roflgs = tmr->head.roflgs;
+    ERTS_HLT_ASSERT(esdp == erts_get_scheduler_data());
+    ERTS_HLT_ASSERT((tmr->head.roflgs & ERTS_TMR_ROFLG_SID_MASK)
+		    == (Uint32) esdp->no);
+    if (roflgs & ERTS_TMR_ROFLG_HLT) {
+	hlt_delete_timer(esdp, &tmr->hlt);
+	hl_timer_dec_refc(&tmr->hlt, roflgs);
+    }
+    else {
+	cancel_tw_timer(esdp, &tmr->twt);
+	tw_timer_dec_refc(&tmr->twt);
+    }
+}
+
+#ifdef ERTS_SMP
+
+static void
+init_canceled_queue(ErtsHLTCncldTmrQ *cq)
+{
+    erts_atomic_init_nob(&cq->tail.data.marker.u.next, ERTS_AINT_NULL);
+    erts_atomic_init_nob(&cq->tail.data.last,
+			 (erts_aint_t) &cq->tail.data.marker);
+    cq->head.first = (ErtsTimer *) &cq->tail.data.marker;
+    cq->head.unref_end = (ErtsTimer *) &cq->tail.data.marker;
+    cq->head.next.thr_progress = erts_thr_progress_current();
+    cq->head.next.thr_progress_reached = 1;
+    cq->head.next.unref_end = (ErtsTimer *) &cq->tail.data.marker;
+    cq->head.used_marker = 1;
+}
+
+static ERTS_INLINE int
+cq_enqueue(ErtsHLTCncldTmrQ *cq, ErtsTimer *tmr, int cinit)
+{
+    erts_aint_t itmp;
+    ErtsTimer *enq, *this = tmr;
+
+    erts_atomic_init_nob(&this->head.u.next, ERTS_AINT_NULL);
+    /* Enqueue at end of list... */
+
+    enq = (ErtsTimer *) erts_atomic_read_nob(&cq->tail.data.last);
+    itmp = erts_atomic_cmpxchg_relb(&enq->head.u.next,
+				    (erts_aint_t) this,
+				    ERTS_AINT_NULL);
+    if (itmp == ERTS_AINT_NULL) {
+	/* We are required to move last pointer */
+#ifdef DEBUG
+	ASSERT(ERTS_AINT_NULL == erts_atomic_read_nob(&this->head.u.next));
+	ASSERT(((erts_aint_t) enq)
+	       == erts_atomic_xchg_relb(&cq->tail.data.last,
+					(erts_aint_t) this));
+#else
+	erts_atomic_set_relb(&cq->tail.data.last, (erts_aint_t) this);
+#endif
+	return 1;
+    }
+    else {
+	/*
+	 * We *need* to insert element somewhere in between the
+	 * last element we read earlier and the actual last element.
+	 */
+	int i = cinit;
+
+	while (1) {
+	    erts_aint_t itmp2;
+	    erts_atomic_set_nob(&this->head.u.next, itmp);
+	    itmp2 = erts_atomic_cmpxchg_relb(&enq->head.u.next,
+					     (erts_aint_t) this,
+					     itmp);
+	    if (itmp == itmp2)
+		return 0; /* inserted this */
+	    if ((i & 1) == 0)
+		itmp = itmp2;
+	    else {
+		enq = (ErtsTimer *) itmp2;
+		itmp = erts_atomic_read_acqb(&enq->head.u.next);
+		ASSERT(itmp != ERTS_AINT_NULL);
+	    }
+	    i++;
+	}
+    }
+}
+
+static ERTS_INLINE erts_aint_t
+check_insert_marker(ErtsHLTCncldTmrQ *cq, erts_aint_t ilast)
+{
+    if (!cq->head.used_marker
+	&& cq->head.unref_end == (ErtsTimer *) ilast) {
+	erts_aint_t itmp;
+	ErtsTimer *last = (ErtsTimer *) ilast;
+
+	erts_atomic_init_nob(&cq->tail.data.marker.u.next, ERTS_AINT_NULL);
+	itmp = erts_atomic_cmpxchg_relb(&last->head.u.next,
+					(erts_aint_t) &cq->tail.data.marker,
+					ERTS_AINT_NULL);
+	if (itmp == ERTS_AINT_NULL) {
+	    ilast = (erts_aint_t) &cq->tail.data.marker;
+	    cq->head.used_marker = !0;
+	    erts_atomic_set_relb(&cq->tail.data.last, ilast);
+	}
+    }
+    return ilast;
+}
+
+static ERTS_INLINE ErtsTimer *
+cq_dequeue(ErtsHLTCncldTmrQ *cq)
+{
+    ErtsTimer *tmr;
+
+    if (cq->head.first == cq->head.unref_end)
+	return NULL;
+
+    tmr = cq->head.first;
+    if (tmr == (ErtsTimer *) &cq->tail.data.marker) {
+	ASSERT(cq->head.used_marker);
+	cq->head.used_marker = 0;
+	tmr = (ErtsTimer *) erts_atomic_read_nob(&tmr->head.u.next);
+	if (tmr == cq->head.unref_end) {
+	    cq->head.first = tmr;
+	    return NULL;
+	}
+    }
+
+    cq->head.first = (ErtsTimer *) erts_atomic_read_nob(&tmr->head.u.next);
+
+    ASSERT(cq->head.first);
+
+    return tmr;
+}
+
+static int
+cq_check_incoming(ErtsSchedulerData *esdp, ErtsHLTCncldTmrQ *cq)
+{
+    erts_aint_t ilast = erts_atomic_read_nob(&cq->tail.data.last);
+    if (((ErtsTimer *) ilast) == (ErtsTimer *) &cq->tail.data.marker
+	&& cq->head.first == (ErtsTimer *) &cq->tail.data.marker) {
+	/* Nothing more to do... */
+	return 0;
+    }
+
+    if (cq->head.next.thr_progress_reached
+	|| erts_thr_progress_has_reached(cq->head.next.thr_progress)) {
+	cq->head.next.thr_progress_reached = 1;
+	/* Move unreferenced end pointer forward... */
+
+	ERTS_HLT_SMP_MEMBAR_LoadLoad_LoadStore;
+
+	cq->head.unref_end = cq->head.next.unref_end;
+
+	ilast = check_insert_marker(cq, ilast);
+
+	if (cq->head.unref_end != (ErtsTimer *) ilast) {
+	    cq->head.next.unref_end = (ErtsTimer *) ilast;
+	    cq->head.next.thr_progress = erts_thr_progress_later(esdp);
+	    cq->head.next.thr_progress_reached = 0;
+	}
+    }
+    return 1;
+}
+
+static ERTS_INLINE void
+store_earliest_thr_prgr(ErtsThrPrgrVal *prev_val, ErtsHLTCncldTmrQ *cq)
+{
+    if (!cq->head.next.thr_progress_reached
+	&& (*prev_val == ERTS_THR_PRGR_INVALID
+	    || erts_thr_progress_cmp(cq->head.next.thr_progress,
+				     *prev_val) < 0)) {
+	*prev_val = cq->head.next.thr_progress;
+    }
+}
+
+static void
+handle_canceled_queue(ErtsSchedulerData *esdp,
+		      ErtsHLTCncldTmrQ *cq,
+		      int use_limit,
+		      int ops_limit,
+		      int *need_thr_progress,
+		      ErtsThrPrgrVal *thr_prgr_p,
+		      int *need_more_work)
+{
+    int need_thr_prgr = 0;
+    int need_mr_wrk = 0;
+    int have_checked_incoming = 0;
+    int ops = 0;
+
+    ERTS_HLT_ASSERT(cq == &esdp->timer_service->canceled_queue);
+
+    while (1) {
+	ErtsTimer *tmr = cq_dequeue(cq);
+
+	if (tmr)
+	    cleanup_sched_local_canceled_timer(esdp, tmr);
+	else {
+	    if (have_checked_incoming)
+		break;
+	    need_thr_prgr = cq_check_incoming(esdp, cq);
+	    if (need_thr_progress) {
+		*need_thr_progress |= need_thr_prgr;
+		if (need_thr_prgr)
+		    store_earliest_thr_prgr(thr_prgr_p, cq);
+	    }
+	    have_checked_incoming = 1;
+	    continue;
+	}
+
+	if (use_limit && ++ops >= ops_limit) {
+	    if (cq->head.first != cq->head.unref_end) {
+		need_mr_wrk = 1;
+		if (need_more_work)
+		    *need_more_work |= 1;
+	    }
+	    break;
+	}
+    }
+
+    if (need_thr_progress && !(need_thr_prgr | need_mr_wrk)) {
+	need_thr_prgr = cq_check_incoming(esdp, cq);
+	*need_thr_progress |= need_thr_prgr;
+	if (need_thr_prgr)
+	    store_earliest_thr_prgr(thr_prgr_p, cq);
+    }
+}
+
+void
+erts_handle_canceled_timers(void *vesdp,
+			    int *need_thr_progress,
+			    ErtsThrPrgrVal *thr_prgr_p,
+			    int *need_more_work)
+{
+    ErtsSchedulerData *esdp = (ErtsSchedulerData *) vesdp;
+    ERTS_HLT_ASSERT(esdp == erts_get_scheduler_data());
+
+    handle_canceled_queue(esdp, &esdp->timer_service->canceled_queue,
+			  1, ERTS_TMR_CANCELED_TIMER_LIMIT,
+			  need_thr_progress, thr_prgr_p,
+			  need_more_work);
+}
+
+#endif /* ERTS_SMP */
+
+static void
+queue_canceled_timer(ErtsSchedulerData *esdp, int rsched_id, ErtsTimer *tmr)
+{
+#ifdef ERTS_SMP
+    ErtsHLTCncldTmrQ *cq;
+    cq = &ERTS_SCHEDULER_IX(rsched_id-1)->timer_service->canceled_queue;
+    if (cq_enqueue(cq, tmr, rsched_id - (int) esdp->no))
+	erts_notify_canceled_timer(esdp, rsched_id);
+#else
+    ERTS_INTERNAL_ERROR("Unexpected enqueue of canceled timer");
+#endif
+}
+
+static void
+continue_cancel_ptimer(ErtsSchedulerData *esdp, ErtsTimer *tmr)
+{
+#ifdef ERTS_SMP
+    Uint32 sid = (tmr->head.roflgs & ERTS_TMR_ROFLG_SID_MASK);
+
+    if (esdp->no != sid)
+	queue_canceled_timer(esdp, sid, tmr);
+    else
+#endif
+	cleanup_sched_local_canceled_timer(esdp, tmr);
+}
+
+/*
+ * BIF timer specific
+ */
+
+Uint erts_bif_timer_memory_size(void)
+{
+    return (Uint) 0;
+}
+
+static BIF_RETTYPE
+setup_bif_timer(Process *c_p, ErtsMonotonicTime timeout_pos,
+		int short_time, Eterm rcvr, Eterm acsr,
+		Eterm msg, int wrap)
+{
+    BIF_RETTYPE ret;
+    Eterm ref, tmo_msg, *hp;
+    ErtsHLTimer *tmr;
+    ErtsSchedulerData *esdp;
+    DeclareTmpHeap(tmp_hp, 4, c_p);
+
+    if (is_not_internal_pid(rcvr) && is_not_atom(rcvr))
+	goto badarg;
+
+    esdp = ERTS_PROC_GET_SCHDATA(c_p);
+
+    hp = HAlloc(c_p, REF_THING_SIZE);
+    ref = erts_sched_make_ref_in_buffer(esdp, hp);
+
+    ASSERT(erts_get_ref_numbers_thr_id(
+	       internal_ref_numbers(ref)) == (Uint32) esdp->no);
+
+    UseTmpHeap(4, c_p);
+
+    tmo_msg = wrap ? TUPLE3(tmp_hp, am_timeout, ref, msg) : msg;
+
+    tmr = create_hl_timer(esdp, timeout_pos, short_time, 1, NULL, 
+			  rcvr, acsr, tmo_msg, internal_ref_numbers(ref));
+
+    UnUseTmpHeap(4, c_p);
+
+    if (is_internal_pid(rcvr)) {
+	Process *proc = erts_pid2proc_opt(c_p, ERTS_PROC_LOCK_MAIN,
+					  rcvr, ERTS_PROC_LOCK_BTM,
+					  ERTS_P2P_FLG_INC_REFC);
+	if (!proc) {
+	    hlt_delete_timer(esdp, tmr);
+	    hl_timer_destroy(tmr);
+	}
+	else {
+	    proc_btm_rbt_insert(&proc->bif_timers, tmr);
+	    erts_smp_proc_unlock(proc, ERTS_PROC_LOCK_BTM);
+	    tmr->receiver.proc = proc;
+	}
+    }
+
+    ERTS_BIF_PREP_RET(ret, ref);
+    return ret;
+
+badarg:
+
+    ERTS_BIF_PREP_ERROR(ret, c_p, BADARG);
+    return ret;
+}
+
+static int
+cancel_bif_timer(ErtsHLTimer *tmr)
+{
+    erts_aint_t state;
+    Uint32 roflgs;
+    int res;
+
+    state = erts_smp_atomic32_cmpxchg_acqb(&tmr->state,
+					   ERTS_TMR_STATE_CANCELED,
+					   ERTS_TMR_STATE_ACTIVE);
+    if (state != ERTS_TMR_STATE_ACTIVE)
+	return 0;
+
+    res = -1;
+
+    roflgs = tmr->head.roflgs;
+    if (roflgs & ERTS_TMR_ROFLG_PROC) {
+	Process *proc = tmr->receiver.proc;
+	ERTS_HLT_ASSERT(!(tmr->head.roflgs & ERTS_TMR_ROFLG_REG_NAME));
+
+	erts_smp_proc_lock(proc, ERTS_PROC_LOCK_BTM);
+	/*
+	 * If process is exiting, let it clean up
+	 * the btm tree by itself (it may be in
+	 * the middle of tree destruction).
+	 */
+	if (!ERTS_PROC_IS_EXITING(proc)
+	    && tmr->btm.proc_tree.parent != ERTS_HLT_PFIELD_NOT_IN_TABLE) {
+	    proc_btm_rbt_delete(&proc->bif_timers, tmr);
+	    tmr->btm.proc_tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+	    res = 1;
+	}
+	erts_smp_proc_unlock(proc, ERTS_PROC_LOCK_BTM);
+    }
+
+    return res;
+}
+
+static ERTS_INLINE Eterm
+access_sched_local_btm(Process *c_p, Eterm pid,
+		       Eterm tref, Uint32 *trefn,
+		       Uint32 *rrefn,
+		       int async, int cancel,
+		       int return_res,
+		       int info)
+{
+    ErtsSchedulerData *esdp;
+    ErtsHLTimerService *srv;
+    ErtsHLTimer *tmr;
+    Sint64 time_left;
+    Process *proc;
+    ErtsProcLocks proc_locks;
+
+    time_left = -1;
+
+    if (!c_p)
+	esdp = erts_get_scheduler_data();
+    else {
+	esdp = ERTS_PROC_GET_SCHDATA(c_p);
+	ERTS_HLT_ASSERT(esdp == erts_get_scheduler_data());
+    }
+
+    ERTS_HLT_ASSERT(erts_get_ref_numbers_thr_id(trefn)
+		    == (Uint32) esdp->no);
+
+    srv = esdp->timer_service;
+
+    tmr = btm_rbt_lookup(srv->btm_tree, trefn);
+    if (tmr) {
+	if (!cancel) {
+	    erts_aint32_t state = erts_smp_atomic32_read_acqb(&tmr->state);
+	    if (state == ERTS_TMR_STATE_ACTIVE)
+		time_left = get_time_left(esdp, tmr->timeout);
+	}
+	else {
+	    int cncl_res = cancel_bif_timer(tmr);
+	    if (cncl_res) {
+
+		time_left = get_time_left(esdp, tmr->timeout);
+
+		if (cncl_res > 0)
+		    hl_timer_dec_refc(tmr, tmr->head.roflgs);
+
+		hlt_delete_timer(esdp, tmr);
+	    }
+	}
+    }
+
+    if (!info)
+	return am_ok;
+
+    if (return_res) {
+	ERTS_HLT_ASSERT(c_p);
+	if (time_left < 0)
+	    return am_false;
+	else if (time_left <= (Sint64) MAX_SMALL)
+	    return make_small((Sint) time_left);
+	else {
+	    Uint hsz = ERTS_SINT64_HEAP_SIZE(time_left);
+	    Eterm *hp = HAlloc(c_p, hsz);
+	    return erts_sint64_to_big(time_left, &hp);
+	}
+    }
+
+    if (c_p) {
+	proc = c_p;
+	proc_locks = ERTS_PROC_LOCK_MAIN;
+    }
+    else {
+	proc = erts_proc_lookup(pid);
+	proc_locks = 0;
+    }
+
+    if (proc) {
+	Uint hsz;
+	ErlOffHeap *ohp;
+	ErlHeapFragment* bp;
+	Eterm *hp, msg, ref, result;
+#ifdef ERTS_HLT_DEBUG
+	Eterm *hp_end;
+#endif
+
+	hsz = 3; /* 2-tuple */
+	if (!async)
+	    hsz += REF_THING_SIZE;
+	else {
+	    if (is_non_value(tref))
+		hsz += REF_THING_SIZE;
+	    hsz += 1; /* upgrade to 3-tuple */
+	}
+	if (time_left > (Sint64) MAX_SMALL)
+	    hsz += ERTS_SINT64_HEAP_SIZE(time_left);
+
+	hp = erts_alloc_message_heap(hsz,
+				     &bp,
+				     &ohp,
+				     proc,
+				     &proc_locks);
+
+#ifdef ERTS_HLT_DEBUG
+	hp_end = hp + hsz;
+#endif
+
+	if (time_left < 0)
+	    result = am_false;
+	else if (time_left <= (Sint64) MAX_SMALL)
+	    result = make_small((Sint) time_left);
+	else
+	    result = erts_sint64_to_big(time_left, &hp);
+
+	if (!async) {
+	    write_ref_thing(hp,
+			    rrefn[0],
+			    rrefn[1],
+			    rrefn[2]);
+	    ref = make_internal_ref(hp);
+	    hp += REF_THING_SIZE;
+	    msg = TUPLE2(hp, ref, result);
+
+	    ERTS_HLT_ASSERT(hp + 3 == hp_end);
+	}
+	else {
+	    Eterm tag = cancel ? am_cancel_timer : am_read_timer;
+	    if (is_value(tref))
+		ref = tref;
+	    else {
+		write_ref_thing(hp,
+				trefn[0],
+				trefn[1],
+				trefn[2]);
+		ref = make_internal_ref(hp);
+		hp += REF_THING_SIZE;
+	    }
+	    msg = TUPLE3(hp, tag, ref, result);
+
+	    ERTS_HLT_ASSERT(hp + 4 == hp_end);
+
+	}
+	erts_queue_message(proc, &proc_locks, bp,
+			   msg, NIL
+#ifdef USE_VM_PROBES
+			   , NIL
+#endif
+	    );
+
+	if (c_p)
+	    proc_locks &= ~ERTS_PROC_LOCK_MAIN;
+	if (proc_locks)
+	    erts_smp_proc_unlock(proc, proc_locks);
+    }
+
+    return am_ok;
+}
+
+#define ERTS_BTM_REQ_FLG_ASYNC		(((Uint32) 1) << 0)
+#define ERTS_BTM_REQ_FLG_CANCEL		(((Uint32) 1) << 1)
+#define ERTS_BTM_REQ_FLG_INFO		(((Uint32) 1) << 2)
+
+typedef struct {
+    Eterm pid;
+    Uint32 trefn[ERTS_REF_NUMBERS];
+    Uint32 rrefn[ERTS_REF_NUMBERS];
+    Uint32 flags;
+} ErtsBifTimerRequest;
+
+static void
+bif_timer_access_request(void *vreq)
+{
+    ErtsBifTimerRequest *req = (ErtsBifTimerRequest *) vreq;
+    int async = (int) (req->flags & ERTS_BTM_REQ_FLG_ASYNC);
+    int cancel = (int) (req->flags & ERTS_BTM_REQ_FLG_CANCEL);
+    int info = (int) (req->flags & ERTS_BTM_REQ_FLG_INFO);
+    (void) access_sched_local_btm(NULL, req->pid, THE_NON_VALUE,
+				  req->trefn, req->rrefn, async,
+				  cancel, 0, info);
+    erts_free(ERTS_ALC_T_TIMER_REQUEST, vreq);
+}
+
+static int
+try_access_sched_remote_btm(ErtsSchedulerData *esdp,
+			    Process *c_p, Uint32 sid,
+			    Eterm tref, Uint32 *trefn,
+			    int async, int cancel,
+			    int info, Eterm *resp)
+{
+    ErtsHLTimer *tmr;
+    Sint64 time_left;
+
+    ERTS_HLT_ASSERT(c_p);
+
+    /*
+     * Check if the timer is aimed at current
+     * process of if this process is an accessor
+     * of the timer...
+     */
+    erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_BTM);
+    tmr = proc_btm_rbt_lookup(c_p->bif_timers, trefn);
+    if (!tmr)
+	tmr = abtm_rbt_lookup(c_p->accessor_bif_timers, trefn);
+    erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_BTM);
+    if (!tmr)
+	return 0;
+
+    if (!cancel) {
+	erts_aint32_t state = erts_smp_atomic32_read_acqb(&tmr->state);
+	if (state == ERTS_TMR_STATE_ACTIVE)
+	    time_left = get_time_left(esdp, tmr->timeout);
+	else
+	    time_left = -1;
+    }
+    else {
+	int cncl_res = cancel_bif_timer(tmr);
+	if (!cncl_res)
+	    time_left = -1;
+	else {
+	    time_left = get_time_left(esdp, tmr->timeout);
+	    if (cncl_res > 0)
+		queue_canceled_timer(esdp, sid, (ErtsTimer *) tmr);
+	}
+    }
+
+    if (!info) {
+	*resp = am_ok;
+	return 1;
+    }
+
+    if (!async) {
+	if (time_left < 0)
+	    *resp = am_false;
+	else if (time_left <= (Sint64) MAX_SMALL)
+	    *resp = make_small((Sint) time_left);
+	else {
+	    Uint hsz = ERTS_SINT64_HEAP_SIZE(time_left);
+	    Eterm *hp = HAlloc(c_p, hsz);
+	    *resp = erts_sint64_to_big(time_left, &hp);
+	}
+    }
+    else {
+	Eterm tag, res, msg;
+	ErlOffHeap *ohp;
+	ErlHeapFragment* bp;
+	Uint hsz;
+	Eterm *hp;
+	ErtsProcLocks proc_locks = ERTS_PROC_LOCK_MAIN;
+
+	hsz = 4;
+	if (time_left > (Sint64) MAX_SMALL)
+	    hsz += ERTS_SINT64_HEAP_SIZE(time_left);
+
+	hp = erts_alloc_message_heap(hsz,
+				     &bp,
+				     &ohp,
+				     c_p,
+				     &proc_locks);
+	if (cancel)
+	    tag = am_cancel_timer;
+	else
+	    tag = am_read_timer;
+
+	if (time_left < 0)
+	    res = am_false;
+	else if (time_left <= (Sint64) MAX_SMALL)
+	    res = make_small((Sint) time_left);
+	else
+	    res = erts_sint64_to_big(time_left, &hp);
+
+	msg = TUPLE3(hp, tag, tref, res);
+
+	erts_queue_message(c_p, &proc_locks, bp,
+			   msg, NIL
+#ifdef USE_VM_PROBES
+			   , NIL
+#endif
+	    );
+
+	proc_locks &= ~ERTS_PROC_LOCK_MAIN;
+	if (proc_locks)
+	    erts_smp_proc_unlock(c_p, proc_locks);
+
+	*resp = am_ok;
+    }
+    return 1;
+}
+
+static BIF_RETTYPE
+access_bif_timer(Process *c_p, Eterm tref, int cancel, int async, int info)
+{
+    BIF_RETTYPE ret;
+    ErtsSchedulerData *esdp;
+    Uint32 sid;
+    Uint32 *trefn;
+    Eterm res;
+
+    if (is_not_internal_ref(tref)) {
+	if (is_not_ref(tref))
+	    goto badarg;
+	else
+	    goto no_timer;
+    }
+
+    esdp = ERTS_PROC_GET_SCHDATA(c_p);
+
+    trefn = internal_ref_numbers(tref);
+    sid = erts_get_ref_numbers_thr_id(trefn);
+    if (sid < 1 || erts_no_schedulers < sid)
+	goto no_timer;
+
+    if (sid == (Uint32) esdp->no) {
+	res = access_sched_local_btm(c_p, c_p->common.id,
+				     tref, trefn, NULL,
+				     async, cancel, !async,
+				     info);
+	ERTS_BIF_PREP_RET(ret, res);
+    }
+    else if (try_access_sched_remote_btm(esdp, c_p, sid,
+					 tref, trefn,
+					 async, cancel,
+					 info, &res)) {
+	ERTS_BIF_PREP_RET(ret, res);
+    }
+    else {
+	/*
+	 * Schedule access for execution on
+	 * remote scheduler...
+	 */
+	ErtsBifTimerRequest *req = erts_alloc(ERTS_ALC_T_TIMER_REQUEST,
+					      sizeof(ErtsBifTimerRequest));
+
+	req->flags = 0;
+	if (cancel)
+	    req->flags |= ERTS_BTM_REQ_FLG_CANCEL;
+	if (async)
+	    req->flags |= ERTS_BTM_REQ_FLG_ASYNC;
+	if (info)
+	    req->flags |= ERTS_BTM_REQ_FLG_INFO;
+
+	req->pid = c_p->common.id;
+
+	req->trefn[0] = trefn[0];
+	req->trefn[1] = trefn[1];
+	req->trefn[2] = trefn[2];
+
+	if (async)
+	    ERTS_BIF_PREP_RET(ret, am_ok);
+	else {
+	    Eterm *hp, rref;
+	    Uint32 *rrefn;
+
+	    hp = HAlloc(c_p, REF_THING_SIZE);
+	    rref = erts_sched_make_ref_in_buffer(esdp, hp);
+	    rrefn = internal_ref_numbers(rref);
+
+	    req->rrefn[0] = rrefn[0];
+	    req->rrefn[1] = rrefn[1];
+	    req->rrefn[2] = rrefn[2];
+
+	    erts_smp_proc_lock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
+
+	    if (ERTS_PROC_PENDING_EXIT(c_p))
+		ERTS_VBUMP_ALL_REDS(c_p);
+	    else {
+		/*
+		 * Caller needs to wait for a message containing
+		 * the ref that we just created. No such message
+		 * can exist in callers message queue at this time.
+		 * We therefore move the save pointer of the
+		 * callers message queue to the end of the queue.
+		 *
+		 * NOTE: It is of vital importance that the caller
+		 *       immediately do a receive unconditionaly
+		 *       waiting for the message with the reference;
+		 *       otherwise, next receive will *not* work
+		 *       as expected!
+		 */
+		ERTS_SMP_MSGQ_MV_INQ2PRIVQ(c_p);
+		c_p->msg.save = c_p->msg.last;
+	    }
+	    erts_smp_proc_unlock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
+
+	    ERTS_BIF_PREP_TRAP1(ret, erts_await_result, c_p, rref);
+	}
+
+	erts_schedule_misc_aux_work(sid,
+				    bif_timer_access_request,
+				    (void *) req);
+    }
+
+    return ret;
+
+badarg:
+    ERTS_BIF_PREP_ERROR(ret, c_p, BADARG);
+    return ret;
+
+no_timer:
+    ERTS_BIF_PREP_RET(ret, am_false);
+    return ret;
+    
+}
+
+static ERTS_INLINE int
+bool_arg(Eterm val, int *argp)
+{
+    switch (val) {
+    case am_true: *argp = 1; return 1;
+    case am_false: *argp = 0; return 1;
+    default: return 0;
+    }
+}
+
+static ERTS_INLINE int
+parse_bif_timer_options(Eterm option_list, int *async, int *info,
+			int *abs, Eterm *accessor)
+{
+    Eterm list = option_list;
+
+    if (async)
+	*async = 0;
+    if (info)
+	*info = 0;
+    if (abs)
+	*abs = 0;
+    if (accessor)
+	*accessor = THE_NON_VALUE;
+
+    while (is_list(list)) {
+	Eterm *consp, *tp, opt;
+
+	consp = list_val(list);
+	opt = CAR(consp);
+	if (is_not_tuple(opt))
+	    return 0;
+
+	tp = tuple_val(opt);
+	if (arityval(tp[0]) != 2)
+	    return 0;
+
+	switch (tp[1]) {
+	case am_async:
+	    if (!async || !bool_arg(tp[2], async))
+		return 0;
+	    break;
+	case am_info:
+	    if (!info || !bool_arg(tp[2], info))
+		return 0;
+	    break;
+	case am_abs:
+	    if (!abs || !bool_arg(tp[2], abs))
+		return 0;
+	    break;
+	case am_accessor:
+	    if (!accessor || is_not_internal_pid(tp[2]))
+		return 0;
+	    *accessor = tp[2];
+	    break;
+	default:
+	    return 0;
+	}
+
+	list = CDR(consp);	
+    }
+
+    if (is_not_nil(list))
+	return 0;
+    return 1;
+}
+
+static void
+exit_cancel_bif_timer(ErtsHLTimer *tmr, void *vesdp)
+{
+    ErtsSchedulerData *esdp = (ErtsSchedulerData *) vesdp;
+    Uint32 sid, roflgs;
+    erts_aint_t state;
+
+    state = erts_smp_atomic32_cmpxchg_acqb(&tmr->state,
+					   ERTS_TMR_STATE_CANCELED,
+					   ERTS_TMR_STATE_ACTIVE);
+
+    roflgs = tmr->head.roflgs;
+    sid = roflgs & ERTS_TMR_ROFLG_SID_MASK;
+
+    ERTS_HLT_ASSERT(sid == erts_get_ref_numbers_thr_id(tmr->btm.refn));
+    ERTS_HLT_ASSERT(tmr->btm.proc_tree.parent
+		    != ERTS_HLT_PFIELD_NOT_IN_TABLE);
+
+    tmr->btm.proc_tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+
+    if (sid == (Uint32) esdp->no) {
+	if (state == ERTS_TMR_STATE_ACTIVE)
+	    hlt_delete_timer(esdp, tmr);
+	hl_timer_dec_refc(tmr, roflgs);
+    }
+    else {
+	if (state == ERTS_TMR_STATE_ACTIVE)
+	    queue_canceled_timer(esdp, sid, (ErtsTimer *) tmr);
+	else
+	    hl_timer_dec_refc(tmr, roflgs);
+    }
+}
+
+#ifdef ERTS_HLT_DEBUG
+#  define ERTS_BTM_MAX_DESTROY_LIMIT 2
+#else
+#  define ERTS_BTM_MAX_DESTROY_LIMIT 50
+#endif
+
+typedef struct {
+    ErtsBifTimers *bif_timers;
+    union {
+	proc_btm_rbt_yield_state_t proc_btm_yield_state;
+	abtm_rbt_yield_state_t abtm_yield_state;
+    } u;
+} ErtsBifTimerYieldState;
+
+int erts_cancel_bif_timers(Process *p, ErtsBifTimers *btm, void **vyspp)
+{
+    ErtsSchedulerData *esdp = ERTS_PROC_GET_SCHDATA(p);
+    ErtsBifTimerYieldState ys = {btm, {ERTS_RBT_YIELD_STAT_INITER}};
+    ErtsBifTimerYieldState *ysp;
+    int res;
+
+    ysp = (ErtsBifTimerYieldState *) *vyspp;
+    if (!ysp)
+	ysp = &ys;
+
+    res = proc_btm_rbt_foreach_destroy_yielding(&ysp->bif_timers,
+						exit_cancel_bif_timer,
+						(void *) esdp,
+						&ysp->u.proc_btm_yield_state,
+						ERTS_BTM_MAX_DESTROY_LIMIT);
+
+    if (res == 0) {
+	if (ysp != &ys)
+	    erts_free(ERTS_ALC_T_BTM_YIELD_STATE, ysp);
+	*vyspp = NULL;
+    }
+    else {
+
+	if (ysp == &ys) {
+	    ysp = erts_alloc(ERTS_ALC_T_BTM_YIELD_STATE,
+			     sizeof(ErtsBifTimerYieldState));
+	    sys_memcpy((void *) ysp, (void *) &ys,
+		       sizeof(ErtsBifTimerYieldState));
+	}
+
+	*vyspp = (void *) ysp;
+    }
+
+    return res;
+}
+
+static void
+detach_bif_timer(ErtsHLTimer *tmr, void *vesdp)
+{
+    tmr->abtm.tree.parent = ERTS_HLT_PFIELD_NOT_IN_TABLE;
+    hl_timer_dec_refc(tmr, tmr->head.roflgs);
+}
+
+int erts_detach_accessor_bif_timers(Process *p, ErtsBifTimers *btm, void **vyspp)
+{
+    ErtsSchedulerData *esdp = ERTS_PROC_GET_SCHDATA(p);
+    ErtsBifTimerYieldState ys = {btm, {ERTS_RBT_YIELD_STAT_INITER}};
+    ErtsBifTimerYieldState *ysp;
+    int res;
+
+    ysp = (ErtsBifTimerYieldState *) *vyspp;
+    if (!ysp)
+	ysp = &ys;
+
+    res = abtm_rbt_foreach_destroy_yielding(&ysp->bif_timers,
+					    detach_bif_timer,
+					    (void *) esdp,
+					    &ysp->u.abtm_yield_state,
+					    ERTS_BTM_MAX_DESTROY_LIMIT);
+
+    if (res == 0) {
+	if (ysp != &ys)
+	    erts_free(ERTS_ALC_T_BTM_YIELD_STATE, ysp);
+	*vyspp = NULL;
+    }
+    else {
+
+	if (ysp == &ys) {
+	    ysp = erts_alloc(ERTS_ALC_T_BTM_YIELD_STATE,
+			     sizeof(ErtsBifTimerYieldState));
+	    sys_memcpy((void *) ysp, (void *) &ys,
+		       sizeof(ErtsBifTimerYieldState));
+	}
+
+	*vyspp = (void *) ysp;
+    }
+
+    return res;
+}
+
+static ERTS_INLINE int
+parse_timeout_pos(ErtsSchedulerData *esdp, Eterm arg,
+		  ErtsMonotonicTime *conv_arg, int abs,
+		  ErtsMonotonicTime *tposp, int *stimep)
+{
+    ErtsMonotonicTime t;
+
+    if (!term_to_Sint64(arg, &t)) {
+	ERTS_HLT_ASSERT(!is_small(arg));
+	if (!is_big(arg))
+	    return -1;
+
+	if (abs || !big_sign(arg))
+	    return 1;
+
+	return -1;
+    }
+
+    if (conv_arg)
+	*conv_arg = t;
+
+    if (abs) {
+	t += -1*ERTS_MONOTONIC_OFFSET_MSEC; /* external to internal */
+	if (t < ERTS_MONOTONIC_TO_MSEC(ERTS_MONOTONIC_BEGIN))
+	    return 1;
+	if (t > ERTS_MONOTONIC_TO_MSEC(ERTS_MONOTONIC_END))
+	    return 1;
+	*stimep = (t - ERTS_MONOTONIC_TO_MSEC(esdp->last_monotonic_time)
+		   < ERTS_BIF_TIMER_SHORT_TIME);
+	*tposp = ERTS_MSEC_TO_CLKTCKS(t);
+    }
+    else {
+	ErtsMonotonicTime now, ticks;
+	
+	if (t < 0)
+	    return -1;
+
+	ticks = ERTS_MSEC_TO_CLKTCKS(t);
+
+	if (ERTS_CLKTCK_RESOLUTION > 1000 && ticks < 0)
+	    return 1;
+
+	ERTS_HLT_ASSERT(ticks >= 0);
+
+	now = erts_get_monotonic_time(esdp);
+	ticks += ERTS_MONOTONIC_TO_CLKTCKS(now-1);
+	ticks += 1;
+
+	if (ticks < ERTS_MONOTONIC_TO_CLKTCKS(ERTS_MONOTONIC_BEGIN))
+	    return 1;
+	if (ticks > ERTS_MONOTONIC_TO_CLKTCKS(ERTS_MONOTONIC_END))
+	    return 1;
+
+	*stimep = (t < ERTS_BIF_TIMER_SHORT_TIME);
+	*tposp = ticks;
+    }
+
+    return 0;
+}
+
+/*
+ *
+ * The BIF timer BIFs...
+ */
+
+BIF_RETTYPE send_after_3(BIF_ALIST_3)
+{
+    ErtsMonotonicTime timeout_pos;
+    int short_time, tres;
+
+    tres = parse_timeout_pos(ERTS_PROC_GET_SCHDATA(BIF_P), BIF_ARG_1, NULL,
+			     0, &timeout_pos, &short_time);
+    if (tres != 0)
+	BIF_ERROR(BIF_P, tres < 0 ? BADARG : SYSTEM_LIMIT);
+
+    return setup_bif_timer(BIF_P, timeout_pos, short_time,
+			   BIF_ARG_2, BIF_ARG_2, BIF_ARG_3, 0);
+}
+
+BIF_RETTYPE send_after_4(BIF_ALIST_4)
+{
+    ErtsMonotonicTime timeout_pos;
+    Eterm accessor;
+    int short_time, abs, tres;
+
+    if (!parse_bif_timer_options(BIF_ARG_4, NULL, NULL, &abs, &accessor))
+	BIF_ERROR(BIF_P, BADARG);
+    
+    tres = parse_timeout_pos(ERTS_PROC_GET_SCHDATA(BIF_P), BIF_ARG_1, NULL,
+			     abs, &timeout_pos, &short_time);
+    if (tres != 0)
+	BIF_ERROR(BIF_P, tres < 0 ? BADARG : SYSTEM_LIMIT);
+
+    return setup_bif_timer(BIF_P, timeout_pos, short_time,
+			   BIF_ARG_2, accessor, BIF_ARG_3, 0);
+}
+
+BIF_RETTYPE start_timer_3(BIF_ALIST_3)
+{
+    ErtsMonotonicTime timeout_pos;
+    int short_time, tres;
+
+    tres = parse_timeout_pos(ERTS_PROC_GET_SCHDATA(BIF_P), BIF_ARG_1, NULL,
+			     0, &timeout_pos, &short_time);
+    if (tres != 0)
+	BIF_ERROR(BIF_P, tres < 0 ? BADARG : SYSTEM_LIMIT);
+
+    return setup_bif_timer(BIF_P, timeout_pos, short_time,
+			   BIF_ARG_2, BIF_ARG_2, BIF_ARG_3, !0);
+}
+
+BIF_RETTYPE start_timer_4(BIF_ALIST_4)
+{
+    ErtsMonotonicTime timeout_pos;
+    Eterm accessor;
+    int short_time, abs, tres;
+
+    if (!parse_bif_timer_options(BIF_ARG_4, NULL, NULL, &abs, &accessor))
+	BIF_ERROR(BIF_P, BADARG);
+
+    tres = parse_timeout_pos(ERTS_PROC_GET_SCHDATA(BIF_P), BIF_ARG_1, NULL,
+			     abs, &timeout_pos, &short_time);
+    if (tres != 0)
+	BIF_ERROR(BIF_P, tres < 0 ? BADARG : SYSTEM_LIMIT);
+
+    return setup_bif_timer(BIF_P, timeout_pos, short_time,
+			   BIF_ARG_2, accessor, BIF_ARG_3, !0);
+}
+
+BIF_RETTYPE cancel_timer_1(BIF_ALIST_1)
+{
+    return access_bif_timer(BIF_P, BIF_ARG_1, 1, 0, 1);
+}
+
+BIF_RETTYPE cancel_timer_2(BIF_ALIST_2)
+{
+    BIF_RETTYPE ret;
+    int async, info;
+
+    if (parse_bif_timer_options(BIF_ARG_2, &async, &info, NULL, NULL))
+	return access_bif_timer(BIF_P, BIF_ARG_1, 1, async, info);
+
+    ERTS_BIF_PREP_ERROR(ret, BIF_P, BADARG);
+    return ret;
+}
+
+BIF_RETTYPE read_timer_1(BIF_ALIST_1)
+{
+    return access_bif_timer(BIF_P, BIF_ARG_1, 0, 0, 1);
+}
+
+BIF_RETTYPE read_timer_2(BIF_ALIST_2)
+{
+    BIF_RETTYPE ret;
+    int async;
+
+    if (parse_bif_timer_options(BIF_ARG_2, &async, NULL, NULL, NULL))
+	return access_bif_timer(BIF_P, BIF_ARG_1, 0, async, 1);
+
+    ERTS_BIF_PREP_ERROR(ret, BIF_P, BADARG);
+    return ret;
+}
+
+/*
+ * Process and Port timer functionality.
+ *
+ * NOTE! These are only allowed to be called by a
+ *       scheduler thread that currently is
+ *       executing the process or port.
+ */
+
+static ERTS_INLINE void
+set_proc_timer_common(Process *c_p, ErtsSchedulerData *esdp, Sint64 tmo,
+		      ErtsMonotonicTime timeout_pos, int short_time)
+{
+    void *tmr;
+    check_canceled_queue(esdp, esdp->timer_service);
+
+    if (tmo == 0)
+	c_p->flags |= F_TIMO;
+    else {
+
+	c_p->flags |= F_INSLPQUEUE;
+	c_p->flags &= ~F_TIMO;
+
+	if (tmo < ERTS_TIMER_WHEEL_MSEC)
+	    tmr = (void *) create_tw_timer(esdp, (void *) c_p, 1, timeout_pos);
+	else
+	    tmr = (void *) create_hl_timer(esdp, timeout_pos,
+					   short_time, 0, (void *) c_p,
+					   c_p->common.id, NIL, NIL, NULL);
+	erts_smp_atomic_set_relb(&c_p->common.timer, (erts_aint_t) tmr);
+    }
+}
+
+int
+erts_set_proc_timer_term(Process *c_p, Eterm etmo)
+{
+    ErtsSchedulerData *esdp = ERTS_PROC_GET_SCHDATA(c_p);
+    ErtsMonotonicTime tmo, timeout_pos;
+    int short_time, tres;
+
+    ERTS_HLT_ASSERT(erts_smp_atomic_read_nob(&c_p->common.timer)
+		    == ERTS_PTMR_NONE);
+
+    tres = parse_timeout_pos(esdp, etmo, &tmo, 0,
+			     &timeout_pos, &short_time);
+    if (tres != 0)
+	return tres;
+
+    if ((tmo >> 32) != 0)
+	return 1;
+
+    set_proc_timer_common(c_p, esdp, tmo, timeout_pos, short_time);
+    return 0;
+}
+
+void
+erts_set_proc_timer_uword(Process *c_p, UWord tmo)
+{
+    ErtsSchedulerData *esdp = ERTS_PROC_GET_SCHDATA(c_p);
+
+    ERTS_HLT_ASSERT(erts_smp_atomic_read_nob(&c_p->common.timer)
+		    == ERTS_PTMR_NONE);
+
+#ifndef ARCH_32
+    ERTS_HLT_ASSERT((tmo >> 32) == (UWord) 0);
+#endif
+
+    if (tmo == 0)
+	c_p->flags |= F_TIMO;
+    else {
+	ErtsMonotonicTime timeout_pos;
+	timeout_pos = get_timeout_pos(erts_get_monotonic_time(esdp),
+				      (ErtsMonotonicTime) tmo);
+	set_proc_timer_common(c_p, esdp, (ErtsMonotonicTime) tmo,
+			      timeout_pos,
+			      tmo < ERTS_BIF_TIMER_SHORT_TIME);
+    }
+}
+
+void
+erts_cancel_proc_timer(Process *c_p)
+{
+    erts_aint_t tval;
+    tval = erts_smp_atomic_xchg_acqb(&c_p->common.timer,
+				     ERTS_PTMR_NONE);
+    c_p->flags &= ~(F_INSLPQUEUE|F_TIMO);
+    if (tval == ERTS_PTMR_NONE)
+	return;
+    if (tval == ERTS_PTMR_TIMEDOUT) {
+	erts_smp_atomic_set_nob(&c_p->common.timer, ERTS_PTMR_NONE);
+	return;
+    }
+    continue_cancel_ptimer(ERTS_PROC_GET_SCHDATA(c_p),
+			   (ErtsTimer *) tval);
+}
+
+void
+erts_set_port_timer(Port *c_prt, Sint64 tmo)
+{
+    void *tmr;
+    ErtsSchedulerData *esdp = erts_get_scheduler_data();
+    ErtsMonotonicTime timeout_pos;
+
+    if (erts_smp_atomic_read_nob(&c_prt->common.timer) != ERTS_PTMR_NONE)
+	erts_cancel_port_timer(c_prt);
+
+    check_canceled_queue(esdp, esdp->timer_service);
+
+    timeout_pos = get_timeout_pos(erts_get_monotonic_time(esdp), tmo);
+
+    if (tmo < ERTS_TIMER_WHEEL_MSEC)
+	tmr = (void *) create_tw_timer(esdp, (void *) c_prt, 0,
+				       timeout_pos);
+    else
+	tmr = (void *) create_hl_timer(esdp, timeout_pos, 0, 0,
+				       (void *) c_prt,
+				       c_prt->common.id, NIL, NIL,
+				       NULL);
+    erts_smp_atomic_set_relb(&c_prt->common.timer, (erts_aint_t) tmr);
+}
+
+void
+erts_cancel_port_timer(Port *c_prt)
+{
+    erts_aint_t tval;
+    tval = erts_smp_atomic_xchg_acqb(&c_prt->common.timer,
+				     ERTS_PTMR_NONE);
+    if (tval == ERTS_PTMR_NONE)
+	return;
+    if (tval == ERTS_PTMR_TIMEDOUT) {
+	while (!erts_port_task_is_scheduled(&c_prt->timeout_task))
+	    erts_thr_yield();
+	erts_port_task_abort(&c_prt->timeout_task);
+	erts_smp_atomic_set_nob(&c_prt->common.timer, ERTS_PTMR_NONE);
+	return;
+    }
+    continue_cancel_ptimer(erts_get_scheduler_data(),
+			   (ErtsTimer *) tval);
+}
+
+Sint64
+erts_read_port_timer(Port *c_prt)
+{
+    ErtsTimer *tmr;
+    erts_aint_t itmr;
+    ErtsMonotonicTime timeout_pos;
+
+    itmr = erts_smp_atomic_read_acqb(&c_prt->common.timer);
+    if (itmr == ERTS_PTMR_NONE)
+	return (Sint64) -1;
+    if (itmr == ERTS_PTMR_TIMEDOUT)
+	return (Sint64) 0;
+    tmr = (ErtsTimer *) itmr;
+    if (tmr->head.roflgs & ERTS_TMR_ROFLG_HLT)
+	timeout_pos = tmr->hlt.timeout;
+    else
+	timeout_pos = tmr->twt.tw_tmr.timeout_pos;
+    return get_time_left(NULL, timeout_pos);
+}
+
+/*
+ * Debug stuff...
+ */
+
+typedef struct {
+    int to;
+    void *to_arg;
+    ErtsMonotonicTime now;
+} ErtsBTMPrint;
+
+static void
+btm_print(ErtsHLTimer *tmr, void *vbtmp)
+{
+    ErtsBTMPrint *btmp = (ErtsBTMPrint *) vbtmp;
+    ErtsMonotonicTime left;
+    Eterm receiver;
+
+    if (tmr->timeout <= btmp->now)
+	left = 0;
+    left = ERTS_CLKTCKS_TO_MSEC(tmr->timeout - btmp->now);
+
+    receiver = ((tmr->head.roflgs & ERTS_TMR_ROFLG_REG_NAME)
+		? tmr->receiver.name
+		: tmr->receiver.proc->common.id);
+
+    erts_print(btmp->to, btmp->to_arg,
+	       "=timer:%T\n"
+	       "Message: %T\n"
+	       "Time left: %b64d\n",
+	       receiver,
+	       tmr->btm.message,
+	       (Sint64) left);
+}
+
+void
+erts_print_bif_timer_info(int to, void *to_arg)
+{
+    ErtsBTMPrint btmp;
+    int six;
+
+    if (!ERTS_IS_CRASH_DUMPING)
+	ERTS_INTERNAL_ERROR("Not crash dumping");
+
+    btmp.to = to;
+    btmp.to_arg = to_arg;
+    btmp.now = erts_get_monotonic_time(NULL);
+    btmp.now = ERTS_MONOTONIC_TO_CLKTCKS(btmp.now);
+
+    for (six = 0; six < erts_no_schedulers; six++) {
+	ErtsHLTimerService *srv =
+	    erts_aligned_scheduler_data[six].esd.timer_service;
+	btm_rbt_foreach(srv->btm_tree, btm_print, (void *) &btmp);
+    }
+}
+
+typedef struct {
+    void (*func)(Eterm,
+		 Eterm,
+		 ErlHeapFragment *,
+		 void *);
+    void *arg;
+} ErtsBTMForeachDebug;
+
+static void
+debug_btm_foreach(ErtsHLTimer *tmr, void *vbtmfd)
+{
+    if (erts_smp_atomic32_read_nob(&tmr->state) == ERTS_TMR_STATE_ACTIVE) {
+	ErtsBTMForeachDebug *btmfd = (ErtsBTMForeachDebug *) vbtmfd;
+	(*btmfd->func)(((tmr->head.roflgs & ERTS_TMR_ROFLG_REG_NAME)
+			? tmr->receiver.name
+			: tmr->receiver.proc->common.id),
+		       tmr->btm.message,
+		       tmr->btm.bp,
+		       btmfd->arg);
+    }
+}
+
+void
+erts_debug_bif_timer_foreach(void (*func)(Eterm,
+					  Eterm,
+					  ErlHeapFragment *,
+					  void *),
+			     void *arg)
+{
+    ErtsBTMForeachDebug btmfd;
+    int six;
+
+    btmfd.func = func;
+    btmfd.arg = arg;
+
+    if (!erts_smp_thr_progress_is_blocking())
+	ERTS_INTERNAL_ERROR("Not blocking thread progress");
+
+    for (six = 0; six < erts_no_schedulers; six++) {
+	ErtsHLTimerService *srv =
+	    erts_aligned_scheduler_data[six].esd.timer_service;
+	btm_rbt_foreach(srv->btm_tree,
+			debug_btm_foreach,
+			(void *) &btmfd);
+    }
+}
+
+#ifdef ERTS_HLT_HARD_DEBUG
+
+typedef struct {
+    ErtsHLTimerService *srv;
+    int found_root;
+    ErtsHLTimer **rootpp;
+} ErtsHdbgHLT;
+
+static void
+st_hdbg_func(ErtsHLTimer *tmr, void *vhdbg)
+{
+    ErtsHdbgHLT *hdbg = (ErtsHdbgHLT *) vhdbg;
+    ErtsHLTimer **rootpp;
+    ERTS_HLT_ASSERT(tmr->time.tree.parent & ERTS_HLT_PFLG_SAME_TIME);
+    if (tmr->time.tree.parent == ERTS_HLT_PFLG_SAME_TIME) {
+	ERTS_HLT_ASSERT(tmr != *hdbg->rootpp);
+    }
+    else {
+	rootpp = (ErtsHLTimer **) (tmr->time.tree.parent
+				   & ~ERTS_HLT_PFLG_SAME_TIME);
+	ERTS_HLT_ASSERT(rootpp == hdbg->rootpp);
+	ERTS_HLT_ASSERT(tmr == *rootpp);
+	ERTS_HLT_ASSERT(!hdbg->found_root);
+	hdbg->found_root = 1;
+    }
+    ERTS_HLT_ASSERT(tmr->time.tree.u.l.next->time.tree.u.l.prev == tmr);
+    ERTS_HLT_ASSERT(tmr->time.tree.u.l.prev->time.tree.u.l.next == tmr);
+    ERTS_HLT_ASSERT(btm_rbt_lookup(hdbg->srv->btm_tree, tmr->btm.refn) == tmr);
+}
+
+static void
+tt_hdbg_func(ErtsHLTimer *tmr, void *vhdbg)
+{
+    ErtsHdbgHLT *hdbg = (ErtsHdbgHLT *) vhdbg;
+    ErtsHLTimer *prnt;
+    ERTS_HLT_ASSERT((tmr->time.tree.parent & ERTS_HLT_PFLG_SAME_TIME) == 0);
+    prnt = (ErtsHLTimer *) (tmr->time.tree.parent & ~ERTS_HLT_PFLGS_MASK);
+    if (prnt) {
+	ERTS_HLT_ASSERT(prnt->time.tree.u.t.left == tmr
+			|| prnt->time.tree.u.t.right == tmr);
+    }
+    else {
+	ERTS_HLT_ASSERT(!hdbg->found_root);
+	hdbg->found_root = 1;
+	ERTS_HLT_ASSERT(tmr == *hdbg->rootpp);
+    }
+    if (tmr->time.tree.u.t.left) {
+	prnt = (ErtsHLTimer *) (tmr->time.tree.u.t.left->time.tree.parent
+				& ~ERTS_HLT_PFLGS_MASK);
+	ERTS_HLT_ASSERT(tmr == prnt);
+    }
+    if (tmr->time.tree.u.t.right) {
+	prnt = (ErtsHLTimer *) (tmr->time.tree.u.t.right->time.tree.parent
+				& ~ERTS_HLT_PFLGS_MASK);
+	ERTS_HLT_ASSERT(tmr == prnt);
+    }
+    ERTS_HLT_ASSERT(btm_rbt_lookup(hdbg->srv->btm_tree, tmr->btm.refn) == tmr);
+    if (tmr->time.tree.same_time) {
+	ErtsHdbgHLT st_hdbg;
+	st_hdbg.srv = hdbg->srv;
+	st_hdbg.found_root = 0;
+	st_hdbg.rootpp = &tmr->time.tree.same_time;
+	same_time_list_foreach(tmr->time.tree.same_time, st_hdbg_func, (void *) &st_hdbg);
+	ERTS_HLT_ASSERT(st_hdbg.found_root);
+    }
+}
+
+static void
+bt_hdbg_func(ErtsHLTimer *tmr, void *vhdbg)
+{
+    ErtsHdbgHLT *hdbg = (ErtsHdbgHLT *) vhdbg;
+    ErtsHLTimer *prnt;
+    ERTS_HLT_ASSERT((tmr->btm.tree.parent & ERTS_HLT_PFLG_SAME_TIME) == 0);
+    prnt = (ErtsHLTimer *) (tmr->btm.tree.parent & ~ERTS_HLT_PFLGS_MASK);
+    if (prnt) {
+	ERTS_HLT_ASSERT(prnt->btm.tree.left == tmr
+			|| prnt->btm.tree.right == tmr);
+    }
+    else {
+	ERTS_HLT_ASSERT(!hdbg->found_root);
+	hdbg->found_root = 1;
+	ERTS_HLT_ASSERT(tmr == *hdbg->rootpp);
+    }
+    if (tmr->btm.tree.left) {
+	prnt = (ErtsHLTimer *) (tmr->btm.tree.left->btm.tree.parent
+				& ~ERTS_HLT_PFLGS_MASK);
+	ERTS_HLT_ASSERT(tmr == prnt);
+    }
+    if (tmr->btm.tree.right) {
+	prnt = (ErtsHLTimer *) (tmr->btm.tree.right->btm.tree.parent
+				& ~ERTS_HLT_PFLGS_MASK);
+	ERTS_HLT_ASSERT(tmr == prnt);
+    }
+    if (tmr->pending_timeout) {
+	if (tmr->pending_timeout > 0) /* container > 0 */
+	    ERTS_HLT_ASSERT(tmr->time.tree.parent == ERTS_HLT_PFIELD_NOT_IN_TABLE);
+	else {
+	    ERTS_HLT_ASSERT(tmr->time.tree.parent != ERTS_HLT_PFIELD_NOT_IN_TABLE);
+	    ERTS_HLT_ASSERT(tmr->time.tree.parent & ERTS_HLT_PFLG_SAME_TIME);
+	}
+    }
+    else {
+	ErtsHLTimer *ttmr = time_rbt_lookup(hdbg->srv->time_tree, tmr->timeout);
+	ERTS_HLT_ASSERT(ttmr);
+	if (ttmr != tmr) {
+	    ERTS_HLT_ASSERT(ttmr->time.tree.same_time);
+	    ERTS_HLT_ASSERT(tmr == same_time_list_lookup(ttmr->time.tree.same_time, tmr));
+	}
+    }
+}
+
+static void
+hdbg_chk_srv(ErtsHLTimerService *srv)
+{
+    if (srv->time_tree) {
+	ErtsHdbgHLT hdbg;
+	hdbg.srv = srv;
+	hdbg.found_root = 0;
+	hdbg.rootpp = &srv->time_tree;
+	time_rbt_foreach(srv->time_tree, tt_hdbg_func, (void *) &hdbg);
+	ERTS_HLT_ASSERT(hdbg.found_root);
+    }
+    if (srv->btm_tree) {
+	ErtsHdbgHLT hdbg;
+	hdbg.srv = srv;
+	hdbg.found_root = 0;
+	hdbg.rootpp = &srv->btm_tree;
+	btm_rbt_foreach(srv->btm_tree, bt_hdbg_func, (void *) &hdbg);
+	ERTS_HLT_ASSERT(hdbg.found_root);
+    }
+}
+
+#endif /* ERTS_HLT_HARD_DEBUG */