erts: Add new module 'counters'

1 files changed, 219 insertions, 0 deletions

diff --git a/erts/emulator/beam/erl_bif_counters.c b/erts/emulator/beam/erl_bif_counters.c
new file mode 100644
index 0000000000..a46b462225
--- /dev/null
+++ b/erts/emulator/beam/erl_bif_counters.c
@@ -0,0 +1,219 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2018. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * %CopyrightEnd%
+ */
+
+/*
+ * Purpose:  High performance atomics.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <stddef.h> /* offsetof */
+
+#include "sys.h"
+#include "export.h"
+#include "bif.h"
+#include "erl_threads.h"
+#include "big.h"
+#include "erl_binary.h"
+#include "erl_bif_unique.h"
+#include "erl_map.h"
+
+
+#define COUNTERS_PER_CACHE_LINE (ERTS_CACHE_LINE_SIZE / sizeof(erts_atomic64_t))
+
+typedef struct
+{
+    UWord arity;
+#ifdef DEBUG
+    UWord ulen;
+#endif
+    union {
+        erts_atomic64_t v[COUNTERS_PER_CACHE_LINE];
+        byte cache_line__[ERTS_CACHE_LINE_SIZE];
+    } u[1];
+}CountersRef;
+
+static int counters_destructor(Binary *unused)
+{
+    return 1;
+}
+
+
+static UWord ERTS_INLINE div_ceil(UWord dividend, UWord divisor)
+{
+    return (dividend + divisor - 1) / divisor;
+}
+
+BIF_RETTYPE erts_internal_counters_new_1(BIF_ALIST_1)
+{
+    CountersRef* p;
+    Binary* mbin;
+    UWord ui, vi, cnt;
+    Uint bytes, cache_lines;
+    Eterm* hp;
+
+    if (!term_to_UWord(BIF_ARG_1, &cnt)
+        || cnt == 0) {
+        BIF_ERROR(BIF_P, BADARG);
+    }
+
+    if (cnt > (ERTS_UWORD_MAX / (sizeof(erts_atomic64_t)*2*erts_no_schedulers)))
+        BIF_ERROR(BIF_P, SYSTEM_LIMIT);
+
+    cache_lines = erts_no_schedulers * div_ceil(cnt, COUNTERS_PER_CACHE_LINE);
+    bytes = offsetof(CountersRef, u) + cache_lines * ERTS_CACHE_LINE_SIZE;
+    mbin = erts_create_magic_binary_x(bytes,
+                                      counters_destructor,
+                                      ERTS_ALC_T_ATOMICS,
+                                      0);
+    p = ERTS_MAGIC_BIN_DATA(mbin);
+    p->arity = cnt;
+#ifdef DEBUG
+    p->ulen = cache_lines;
+#endif
+    ASSERT((byte*)&p->u[cache_lines] <= ((byte*)p + bytes));
+    for (ui=0; ui < cache_lines; ui++)
+        for (vi=0; vi < COUNTERS_PER_CACHE_LINE; vi++)
+            erts_atomic64_init_nob(&p->u[ui].v[vi], 0);
+    hp = HAlloc(BIF_P, ERTS_MAGIC_REF_THING_SIZE);
+    return erts_mk_magic_ref(&hp, &MSO(BIF_P), mbin);
+}
+
+static ERTS_INLINE int get_ref(Eterm ref, CountersRef** pp)
+{
+    Binary* mbin;
+    if (!is_internal_magic_ref(ref))
+        return 0;
+
+    mbin = erts_magic_ref2bin(ref);
+    if (ERTS_MAGIC_BIN_DESTRUCTOR(mbin) != counters_destructor)
+        return 0;
+    *pp = ERTS_MAGIC_BIN_DATA(mbin);
+    return 1;
+}
+
+static ERTS_INLINE int get_ref_cnt(Eterm ref, Eterm index,
+                                   CountersRef** pp,
+                                   erts_atomic64_t** app,
+                                   UWord sched_ix)
+{
+    CountersRef* p;
+    UWord ix, ui, vi;
+    if (!get_ref(ref, &p) || !term_to_UWord(index, &ix) || --ix >= p->arity)
+        return 0;
+    ui = (ix / COUNTERS_PER_CACHE_LINE) * erts_no_schedulers + sched_ix;
+    vi = ix % COUNTERS_PER_CACHE_LINE;
+    ASSERT(ui < p->ulen);
+    *pp = p;
+    *app = &p->u[ui].v[vi];
+    return 1;
+}
+
+static ERTS_INLINE int get_ref_my_cnt(Eterm ref, Eterm index,
+                                      CountersRef** pp,
+                                      erts_atomic64_t** app)
+{
+    ErtsSchedulerData *esdp = erts_get_scheduler_data();
+    ASSERT(esdp && !ERTS_SCHEDULER_IS_DIRTY(esdp));
+    return get_ref_cnt(ref, index, pp, app, esdp->no - 1);
+}
+
+static ERTS_INLINE int get_ref_first_cnt(Eterm ref, Eterm index,
+                                         CountersRef** pp,
+                                         erts_atomic64_t** app)
+{
+    return get_ref_cnt(ref, index, pp, app, 0);
+}
+
+static ERTS_INLINE int get_incr(CountersRef* p, Eterm term, erts_aint64_t *valp)
+{
+    return (term_to_Sint64(term, (Sint64*)valp)
+            || term_to_Uint64(term, (Uint64*)valp));
+}
+
+static ERTS_INLINE Eterm bld_counter(Process* proc, CountersRef* p,
+                                     erts_aint64_t val)
+{
+    if (IS_SSMALL(val))
+        return make_small((Sint) val);
+    else {
+        Uint hsz = ERTS_SINT64_HEAP_SIZE(val);
+        Eterm* hp = HAlloc(proc, hsz);
+        return erts_sint64_to_big(val, &hp);
+    }
+}
+
+BIF_RETTYPE erts_internal_counters_get_2(BIF_ALIST_2)
+{
+    CountersRef* p;
+    erts_atomic64_t* ap;
+    erts_aint64_t acc = 0;
+    int j;
+
+    if (!get_ref_first_cnt(BIF_ARG_1, BIF_ARG_2, &p, &ap)) {
+        BIF_ERROR(BIF_P, BADARG);
+    }
+    for (j = erts_no_schedulers; j ; --j) {
+        acc += erts_atomic64_read_nob(ap);
+        ap = (erts_atomic64_t*) ((byte*)ap + ERTS_CACHE_LINE_SIZE);
+    }
+    return bld_counter(BIF_P, p, acc);
+}
+
+BIF_RETTYPE erts_internal_counters_add_3(BIF_ALIST_3)
+{
+    CountersRef* p;
+    erts_atomic64_t* ap;
+    erts_aint64_t incr, sum;
+
+    if (!get_ref_my_cnt(BIF_ARG_1, BIF_ARG_2, &p, &ap)
+        || !get_incr(p, BIF_ARG_3, &incr)) {
+        BIF_ERROR(BIF_P, BADARG);
+    }
+    sum = incr + erts_atomic64_read_nob(ap);
+    erts_atomic64_set_nob(ap, sum);
+    return am_ok;
+}
+
+
+BIF_RETTYPE erts_internal_counters_info_1(BIF_ALIST_1)
+{
+    CountersRef* p;
+    Uint hsz = MAP2_SZ;
+    Eterm *hp;
+    UWord memory;
+    Eterm sz_val, mem_val;
+
+    if (!get_ref(BIF_ARG_1, &p))
+        BIF_ERROR(BIF_P, BADARG);
+
+    memory = erts_magic_ref2bin(BIF_ARG_1)->orig_size;
+    erts_bld_uword(NULL, &hsz, p->arity);
+    erts_bld_uword(NULL, &hsz, memory);
+
+    hp = HAlloc(BIF_P, hsz);
+    sz_val  = erts_bld_uword(&hp, NULL, p->arity);
+    mem_val = erts_bld_uword(&hp, NULL, memory);
+
+    return MAP2(hp, am_memory, mem_val,
+                am_size, sz_val);
+}