aboutsummaryrefslogtreecommitdiffstats
path: root/erts/emulator/beam
diff options
context:
space:
mode:
Diffstat (limited to 'erts/emulator/beam')
-rw-r--r--erts/emulator/beam/erl_db_catree.c141
-rw-r--r--erts/emulator/beam/erl_db_catree.h2
-rw-r--r--erts/emulator/beam/erl_process.h36
3 files changed, 152 insertions, 27 deletions
diff --git a/erts/emulator/beam/erl_db_catree.c b/erts/emulator/beam/erl_db_catree.c
index e0d5e44f58..fed4b44a9b 100644
--- a/erts/emulator/beam/erl_db_catree.c
+++ b/erts/emulator/beam/erl_db_catree.c
@@ -166,8 +166,17 @@ static void split_catree(DbTableCATree *tb,
static void join_catree(DbTableCATree *tb,
DbTableCATreeNode *thiz,
DbTableCATreeNode *parent);
-
-
+static ERTS_INLINE
+int try_wlock_base_node(DbTableCATreeBaseNode *base_node);
+static ERTS_INLINE
+void wunlock_base_node(DbTableCATreeNode *base_node);
+static ERTS_INLINE
+void wlock_base_node_no_stats(DbTableCATreeNode *base_node);
+static ERTS_INLINE
+void wunlock_adapt_base_node(DbTableCATree* tb,
+ DbTableCATreeNode* node,
+ DbTableCATreeNode* parent,
+ int current_level);
/*
** External interface
*/
@@ -210,12 +219,16 @@ DbTableMethod db_catree =
* Constants
*/
-#define ERL_DB_CATREE_LOCK_FAILURE_CONTRIBUTION 200
+#define ERL_DB_CATREE_LOCK_FAILURE_CONTRIBUTION 250
#define ERL_DB_CATREE_LOCK_SUCCESS_CONTRIBUTION (-1)
+#define ERL_DB_CATREE_LOCK_GRAVITY_CONTRIBUTION (-500)
+#define ERL_DB_CATREE_LOCK_GRAVITY_PATTERN (0xFF800000)
#define ERL_DB_CATREE_LOCK_MORE_THAN_ONE_CONTRIBUTION (-10)
#define ERL_DB_CATREE_HIGH_CONTENTION_LIMIT 1000
#define ERL_DB_CATREE_LOW_CONTENTION_LIMIT (-1000)
-#define ERL_DB_CATREE_MAX_ROUTE_NODE_LAYER_HEIGHT 14
+#define ERL_DB_CATREE_MAX_ROUTE_NODE_LAYER_HEIGHT 16
+#define ERL_DB_CATREE_LOCK_LOW_NO_CONTRIBUTION_LIMIT (-20000)
+#define ERL_DB_CATREE_LOCK_HIGH_NO_CONTRIBUTION_LIMIT (20000)
/*
* Internal CA tree related helper functions and macros
@@ -245,6 +258,27 @@ DbTableMethod db_catree =
#define SET_LEFT_RELB(ca_tree_route_node, v) erts_atomic_set_relb(&(ca_tree_route_node->u.route.left), (erts_aint_t)(v));
#define SET_RIGHT_RELB(ca_tree_route_node, v) erts_atomic_set_relb(&(ca_tree_route_node->u.route.right), (erts_aint_t)(v));
+/* Change base node lock statistics */
+#define BASE_NODE_STAT_SET(NODE, VALUE) erts_atomic_set_nob(&(NODE)->u.base.lock_statistics, VALUE)
+#define BASE_NODE_STAT_READ(NODE) erts_atomic_read_nob(&(NODE)->u.base.lock_statistics)
+#define BASE_NODE_STAT_ADD(NODE, VALUE) \
+ do { \
+ Sint v = erts_atomic_read_nob(&((NODE)->u.base.lock_statistics)); \
+ ASSERT(VALUE > 0); \
+ if(v < ERL_DB_CATREE_LOCK_HIGH_NO_CONTRIBUTION_LIMIT) { \
+ erts_atomic_set_nob(&(NODE->u.base.lock_statistics), v + VALUE); \
+ } \
+ }while(0);
+#define BASE_NODE_STAT_SUB(NODE, VALUE) \
+ do { \
+ Sint v = erts_atomic_read_nob(&((NODE)->u.base.lock_statistics)); \
+ ASSERT(VALUE < 0); \
+ if(v > ERL_DB_CATREE_LOCK_LOW_NO_CONTRIBUTION_LIMIT) { \
+ erts_atomic_set_nob(&(NODE->u.base.lock_statistics), v + VALUE); \
+ } \
+ }while(0);
+
+
/* Compares a key to the key in a route node */
static ERTS_INLINE Sint cmp_key_route(Eterm key,
DbTableCATreeNode *obj)
@@ -653,10 +687,10 @@ static void dbg_provoke_random_splitjoin(DbTableCATree* tb,
switch (dbg_fastrand() % 8) {
case 1:
- base_node->u.base.lock_statistics = 1+ERL_DB_CATREE_HIGH_CONTENTION_LIMIT;
+ BASE_NODE_STAT_ADD(base_node, 1+ERL_DB_CATREE_HIGH_CONTENTION_LIMIT);
break;
case 2:
- base_node->u.base.lock_statistics = -1+ERL_DB_CATREE_LOW_CONTENTION_LIMIT;
+ BASE_NODE_STAT_SUB(base_node, -1+ERL_DB_CATREE_LOW_CONTENTION_LIMIT);
break;
}
}
@@ -664,6 +698,48 @@ static void dbg_provoke_random_splitjoin(DbTableCATree* tb,
# define dbg_provoke_random_splitjoin(T,N)
#endif /* PROVOKE_RANDOM_SPLIT_JOIN */
+static ERTS_NOINLINE
+void do_random_join(DbTableCATree* tb, Uint rand)
+{
+ DbTableCATreeNode* node = GET_ROOT_ACQB(tb);
+ DbTableCATreeNode* parent = NULL;
+ int level = 0;
+ Sint stat;
+ while (!node->is_base_node) {
+ parent = node;
+ if ((rand & (1 << level)) == 0) {
+ node = GET_LEFT_ACQB(node);
+ } else {
+ node = GET_RIGHT_ACQB(node);
+ }
+ level++;
+ }
+ BASE_NODE_STAT_SUB(node, ERL_DB_CATREE_LOCK_GRAVITY_CONTRIBUTION);
+ stat = BASE_NODE_STAT_READ(node);
+ if (stat >= ERL_DB_CATREE_LOW_CONTENTION_LIMIT &&
+ stat <= ERL_DB_CATREE_HIGH_CONTENTION_LIMIT) {
+ return; /* No adaptation */
+ }
+ if (parent != NULL && !try_wlock_base_node(&node->u.base)) {
+ if (!node->u.base.is_valid) {
+ wunlock_base_node(node);
+ return;
+ }
+ wunlock_adapt_base_node(tb, node, parent, level);
+ }
+}
+
+static ERTS_INLINE
+void do_random_join_with_low_probability(DbTableCATree* tb, Uint seed)
+{
+#ifndef ERTS_DB_CA_TREE_NO_RANDOM_JOIN_WITH_LOW_PROBABILITY
+ Uint32 rand = erts_sched_local_random(seed);
+ if (((rand & ERL_DB_CATREE_LOCK_GRAVITY_PATTERN)) == 0) {
+ do_random_join(tb, rand);
+ }
+#endif
+}
+
static ERTS_INLINE
int try_wlock_base_node(DbTableCATreeBaseNode *base_node)
{
@@ -691,9 +767,9 @@ void wlock_base_node(DbTableCATreeNode *base_node)
if (try_wlock_base_node(&base_node->u.base)) {
/* The lock is contended */
wlock_base_node_no_stats(base_node);
- base_node->u.base.lock_statistics += ERL_DB_CATREE_LOCK_FAILURE_CONTRIBUTION;
+ BASE_NODE_STAT_ADD(base_node, ERL_DB_CATREE_LOCK_FAILURE_CONTRIBUTION);
} else {
- base_node->u.base.lock_statistics += ERL_DB_CATREE_LOCK_SUCCESS_CONTRIBUTION;
+ BASE_NODE_STAT_SUB(base_node, ERL_DB_CATREE_LOCK_SUCCESS_CONTRIBUTION);
}
}
@@ -709,13 +785,14 @@ void wunlock_adapt_base_node(DbTableCATree* tb,
DbTableCATreeNode* parent,
int current_level)
{
+ Sint base_node_lock_stat = BASE_NODE_STAT_READ(node);
dbg_provoke_random_splitjoin(tb,node);
if ((!node->u.base.root && parent && !(tb->common.status
& DB_CATREE_FORCE_SPLIT))
- || node->u.base.lock_statistics < ERL_DB_CATREE_LOW_CONTENTION_LIMIT) {
+ || base_node_lock_stat < ERL_DB_CATREE_LOW_CONTENTION_LIMIT) {
join_catree(tb, node, parent);
}
- else if (node->u.base.lock_statistics > ERL_DB_CATREE_HIGH_CONTENTION_LIMIT
+ else if (base_node_lock_stat > ERL_DB_CATREE_HIGH_CONTENTION_LIMIT
&& current_level < ERL_DB_CATREE_MAX_ROUTE_NODE_LAYER_HEIGHT) {
split_catree(tb, node, parent);
}
@@ -728,11 +805,23 @@ static ERTS_INLINE
void rlock_base_node(DbTableCATreeNode *base_node)
{
ASSERT(base_node->is_base_node);
- erts_rwmtx_rlock(&base_node->u.base.lock);
+ if (EBUSY == erts_rwmtx_tryrlock(&base_node->u.base.lock)) {
+ /* The lock is contended */
+ BASE_NODE_STAT_ADD(base_node, ERL_DB_CATREE_LOCK_FAILURE_CONTRIBUTION);
+ erts_rwmtx_rlock(&base_node->u.base.lock);
+ }
+}
+
+static ERTS_INLINE
+void runlock_base_node(DbTableCATreeNode *base_node, DbTableCATree* tb)
+{
+ ASSERT(base_node->is_base_node);
+ erts_rwmtx_runlock(&base_node->u.base.lock);
+ do_random_join_with_low_probability(tb, (Uint)base_node);
}
static ERTS_INLINE
-void runlock_base_node(DbTableCATreeNode *base_node)
+void runlock_base_node_no_rand(DbTableCATreeNode *base_node)
{
ASSERT(base_node->is_base_node);
erts_rwmtx_runlock(&base_node->u.base.lock);
@@ -814,7 +903,7 @@ void unlock_iter_base_node(CATreeRootIterator* iter)
{
ASSERT(iter->locked_bnode);
if (iter->read_only)
- runlock_base_node(iter->locked_bnode);
+ runlock_base_node(iter->locked_bnode, iter->tb);
else if (iter->locked_bnode->u.base.is_valid) {
wunlock_adapt_base_node(iter->tb, iter->locked_bnode,
iter->bnode_parent, iter->bnode_level);
@@ -874,7 +963,7 @@ DbTableCATreeNode* find_rlock_valid_base_node(DbTableCATree* tb, Eterm key)
rlock_base_node(base_node);
if (base_node->u.base.is_valid)
break;
- runlock_base_node(base_node);
+ runlock_base_node_no_rand(base_node);
}
return base_node;
}
@@ -923,8 +1012,8 @@ static DbTableCATreeNode *create_base_node(DbTableCATree *tb,
"erl_db_catree_base_node",
NIL,
ERTS_LOCK_FLAGS_CATEGORY_DB);
- p->u.base.lock_statistics = ((tb->common.status & DB_CATREE_FORCE_SPLIT)
- ? INT_MAX : 0);
+ BASE_NODE_STAT_SET(p, ((tb->common.status & DB_CATREE_FORCE_SPLIT)
+ ? INT_MAX : 0));
p->u.base.is_valid = 1;
return p;
}
@@ -1094,7 +1183,7 @@ static void join_catree(DbTableCATree *tb,
ASSERT(thiz->is_base_node);
if (parent == NULL) {
- thiz->u.base.lock_statistics = 0;
+ BASE_NODE_STAT_SET(thiz, 0);
wunlock_base_node(thiz);
return;
}
@@ -1103,11 +1192,11 @@ static void join_catree(DbTableCATree *tb,
neighbor = leftmost_base_node(GET_RIGHT_ACQB(parent));
if (try_wlock_base_node(&neighbor->u.base)) {
/* Failed to acquire lock */
- thiz->u.base.lock_statistics = 0;
+ BASE_NODE_STAT_SET(thiz, 0);
wunlock_base_node(thiz);
return;
} else if (!neighbor->u.base.is_valid) {
- thiz->u.base.lock_statistics = 0;
+ BASE_NODE_STAT_SET(thiz, 0);
wunlock_base_node(thiz);
wunlock_base_node(neighbor);
return;
@@ -1153,11 +1242,11 @@ static void join_catree(DbTableCATree *tb,
neighbor = rightmost_base_node(GET_LEFT_ACQB(parent));
if (try_wlock_base_node(&neighbor->u.base)) {
/* Failed to acquire lock */
- thiz->u.base.lock_statistics = 0;
+ BASE_NODE_STAT_SET(thiz, 0);
wunlock_base_node(thiz);
return;
} else if (!neighbor->u.base.is_valid) {
- thiz->u.base.lock_statistics = 0;
+ BASE_NODE_STAT_SET(thiz, 0);
wunlock_base_node(thiz);
wunlock_base_node(neighbor);
return;
@@ -1241,7 +1330,7 @@ static void split_catree(DbTableCATree *tb,
if (less_than_two_elements(base->u.base.root)) {
if (!(tb->common.status & DB_CATREE_FORCE_SPLIT))
- base->u.base.lock_statistics = 0;
+ BASE_NODE_STAT_SET(base, 0);
wunlock_base_node(base);
return;
} else {
@@ -1521,7 +1610,7 @@ static int db_get_catree(Process *p, DbTable *tbl, Eterm key, Eterm *ret)
int result = db_get_tree_common(p, &tb->common,
node->u.base.root,
key, ret, NULL);
- runlock_base_node(node);
+ runlock_base_node(node, tb);
return result;
}
@@ -1804,7 +1893,7 @@ static int db_member_catree(DbTable *tbl, Eterm key, Eterm *ret)
int result = db_member_tree_common(&tb->common,
node->u.base.root,
key, ret, NULL);
- runlock_base_node(node);
+ runlock_base_node(node, tb);
return result;
}
@@ -1816,7 +1905,7 @@ static int db_get_element_catree(Process *p, DbTable *tbl,
int result = db_get_element_tree_common(p, &tb->common,
node->u.base.root,
key, ndex, ret, NULL);
- runlock_base_node(node);
+ runlock_base_node(node, tb);
return result;
}
@@ -2250,7 +2339,7 @@ void db_catree_force_split(DbTableCATree* tb, int on)
init_root_iterator(tb, &iter, 1);
root = catree_find_first_root(&iter);
do {
- iter.locked_bnode->u.base.lock_statistics = (on ? INT_MAX : 0);
+ BASE_NODE_STAT_SET(iter.locked_bnode, (on ? INT_MAX : 0));
root = catree_find_next_root(&iter, NULL);
} while (root);
destroy_root_iterator(&iter);
diff --git a/erts/emulator/beam/erl_db_catree.h b/erts/emulator/beam/erl_db_catree.h
index cf3498dabb..c2c884eee3 100644
--- a/erts/emulator/beam/erl_db_catree.h
+++ b/erts/emulator/beam/erl_db_catree.h
@@ -42,7 +42,7 @@ typedef struct {
typedef struct {
erts_rwmtx_t lock; /* The lock for this base node */
- Sint lock_statistics;
+ erts_atomic_t lock_statistics;
int is_valid; /* If this base node is still valid */
TreeDbTerm *root; /* The root of the sequential tree */
ErtsThrPrgrLaterOp free_item; /* Used when freeing using thread progress */
diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h
index 6118c671ee..2aeeebbebc 100644
--- a/erts/emulator/beam/erl_process.h
+++ b/erts/emulator/beam/erl_process.h
@@ -2631,6 +2631,9 @@ void erts_notify_inc_runq(ErtsRunQueue *runq);
void erts_sched_finish_poke(ErtsSchedulerSleepInfo *, erts_aint32_t);
ERTS_GLB_INLINE void erts_sched_poke(ErtsSchedulerSleepInfo *ssi);
void erts_aux_thread_poke(void);
+ERTS_GLB_INLINE Uint32 erts_sched_local_random_hash_64_to_32_shift(Uint64 key);
+ERTS_GLB_INLINE Uint32 erts_sched_local_random(Uint additional_seed);
+
#if ERTS_GLB_INLINE_INCL_FUNC_DEF
@@ -2647,6 +2650,39 @@ erts_sched_poke(ErtsSchedulerSleepInfo *ssi)
}
+/*
+ * Source: https://gist.github.com/badboy/6267743
+ * http://web.archive.org/web/20071223173210/http://www.concentric.net/~Ttwang/tech/inthash.htm
+ */
+ERTS_GLB_INLINE
+Uint32 erts_sched_local_random_hash_64_to_32_shift(Uint64 key)
+{
+ key = (~key) + (key << 18); /* key = (key << 18) - key - 1; */
+ key = key ^ (key >> 31);
+ key = (key + (key << 2)) + (key << 4);
+ key = key ^ (key >> 11);
+ key = key + (key << 6);
+ key = key ^ (key >> 22);
+ return (Uint32) key;
+}
+
+/*
+ * This function attempts to return a random number based on the state
+ * of the scheduler, the current process and the additional_seed
+ * parameter.
+ */
+ERTS_GLB_INLINE
+Uint32 erts_sched_local_random(Uint additional_seed)
+{
+ ErtsSchedulerData *esdp = erts_get_scheduler_data();
+ Uint64 seed =
+ additional_seed +
+ esdp->reductions +
+ esdp->current_process->fcalls +
+ (((Uint64)esdp->no) << 32);
+ return erts_sched_local_random_hash_64_to_32_shift(seed);
+}
+
#endif /* #if ERTS_GLB_INLINE_INCL_FUNC_DEF */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 01:51:48 +0000