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-rw-r--r--erts/doc/src/erl.xml26
-rw-r--r--erts/emulator/beam/erl_init.c16
-rw-r--r--erts/emulator/beam/erl_process.c31
-rw-r--r--erts/emulator/beam/erl_process.h2
-rw-r--r--erts/etc/common/erlexec.c1
5 files changed, 66 insertions, 10 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml
index f477280a6f..e36d0adb0d 100644
--- a/erts/doc/src/erl.xml
+++ b/erts/doc/src/erl.xml
@@ -831,14 +831,28 @@
<p>For more information, see
<seealso marker="erlang#system_flag_cpu_topology">erlang:system_flag(cpu_topology, CpuTopology)</seealso>.</p>
</item>
+ <tag><marker id="+swt"><c>+swt very_low|low|medium|high|very_high</c></marker></tag>
+ <item>
+ <p>Set scheduler wakeup threshold. Default is <c>medium</c>.
+ The threshold determines when to wake up sleeping schedulers
+ when more work than can be handled by currently awake schedulers
+ exist. A low threshold will cause earlier wakeups, and a high
+ threshold will cause later wakeups. Early wakeups will
+ distribute work over multiple schedulers faster, but work will
+ more easily bounce between schedulers.
+ </p>
+ <p><em>NOTE:</em> This flag may be removed or changed at any time
+ without prior notice.
+ </p>
+ </item>
+ <tag><marker id="sched_thread_stack_size"><c><![CDATA[+sss size]]></c></marker></tag>
+ <item>
+ <p>Suggested stack size, in kilowords, for scheduler threads.
+ Valid range is 4-8192 kilowords. The default stack size
+ is OS dependent.</p>
+ </item>
</taglist>
</item>
- <tag><marker id="sched_thread_stack_size"><c><![CDATA[+sss size]]></c></marker></tag>
- <item>
- <p>Suggested stack size, in kilowords, for scheduler threads.
- Valid range is 4-8192 kilowords. The default stack size
- is OS dependent.</p>
- </item>
<tag><marker id="+t"><c><![CDATA[+t size]]></c></marker></tag>
<item>
<p>Set the maximum number of atoms the VM can handle. Default is 1048576.</p>
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 14bd10b42c..4ae656a3ad 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -512,6 +512,8 @@ void erts_usage(void)
erts_fprintf(stderr, " u|ns|ts|ps|s|nnts|nnps|tnnps|db\n");
erts_fprintf(stderr, "-sct cput set cpu topology,\n");
erts_fprintf(stderr, " see the erl(1) documentation for more info.\n");
+ erts_fprintf(stderr, "-swt val set scheduler wakeup threshold, valid values are:\n");
+ erts_fprintf(stderr, " very_low|low|medium|high|very_high.\n");
erts_fprintf(stderr, "-sss size suggested stack size in kilo words for scheduler threads,\n");
erts_fprintf(stderr, " valid range is [%d-%d]\n",
ERTS_SCHED_THREAD_MIN_STACK_SIZE,
@@ -1176,10 +1178,20 @@ erl_start(int argc, char **argv)
}
else if (sys_strcmp("mrq", sub_param) == 0)
use_multi_run_queue = 1;
- else if (sys_strcmp("srq", sub_param) == 0)
- use_multi_run_queue = 0;
else if (sys_strcmp("nsp", sub_param) == 0)
erts_use_sender_punish = 0;
+ else if (sys_strcmp("srq", sub_param) == 0)
+ use_multi_run_queue = 0;
+ else if (sys_strcmp("wt", sub_param) == 0) {
+ arg = get_arg(sub_param+2, argv[i+1], &i);
+ if (erts_sched_set_wakeup_limit(arg) != 0) {
+ erts_fprintf(stderr, "scheduler wakeup threshold: %s\n",
+ arg);
+ erts_usage();
+ }
+ VERBOSE(DEBUG_SYSTEM,
+ ("scheduler wakup threshold: %s\n", arg));
+ }
else if (has_prefix("ss", sub_param)) {
/* suggested stack size (Kilo Words) for scheduler threads */
arg = get_arg(sub_param+2, argv[i+1], &i);
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 2609457415..901167a315 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -54,7 +54,12 @@
(ERTS_SCHED_SYS_SLEEP_SPINCOUNT*ERTS_SCHED_TSE_SLEEP_SPINCOUNT_FACT)
#define ERTS_SCHED_SUSPEND_SLEEP_SPINCOUNT 0
-#define ERTS_WAKEUP_OTHER_LIMIT (100*CONTEXT_REDS/2)
+#define ERTS_WAKEUP_OTHER_LIMIT_VERY_HIGH (200*CONTEXT_REDS)
+#define ERTS_WAKEUP_OTHER_LIMIT_HIGH (50*CONTEXT_REDS)
+#define ERTS_WAKEUP_OTHER_LIMIT_MEDIUM (10*CONTEXT_REDS)
+#define ERTS_WAKEUP_OTHER_LIMIT_LOW (CONTEXT_REDS)
+#define ERTS_WAKEUP_OTHER_LIMIT_VERY_LOW (CONTEXT_REDS/10)
+
#define ERTS_WAKEUP_OTHER_DEC 10
#define ERTS_WAKEUP_OTHER_FIXED_INC (CONTEXT_REDS/10)
@@ -112,6 +117,8 @@ Uint erts_no_schedulers;
Uint erts_max_processes = ERTS_DEFAULT_MAX_PROCESSES;
Uint erts_process_tab_index_mask;
+static int wakeup_other_limit;
+
#ifdef ERTS_SMP
Uint erts_max_main_threads;
#endif
@@ -2373,7 +2380,27 @@ void
erts_early_init_scheduling(void)
{
early_cpu_bind_init();
+ wakeup_other_limit = ERTS_WAKEUP_OTHER_LIMIT_MEDIUM;
+}
+
+int
+erts_sched_set_wakeup_limit(char *str)
+{
+ if (sys_strcmp(str, "very_high") == 0)
+ wakeup_other_limit = ERTS_WAKEUP_OTHER_LIMIT_VERY_HIGH;
+ else if (sys_strcmp(str, "high") == 0)
+ wakeup_other_limit = ERTS_WAKEUP_OTHER_LIMIT_HIGH;
+ else if (sys_strcmp(str, "medium") == 0)
+ wakeup_other_limit = ERTS_WAKEUP_OTHER_LIMIT_MEDIUM;
+ else if (sys_strcmp(str, "low") == 0)
+ wakeup_other_limit = ERTS_WAKEUP_OTHER_LIMIT_LOW;
+ else if (sys_strcmp(str, "very_low") == 0)
+ wakeup_other_limit = ERTS_WAKEUP_OTHER_LIMIT_VERY_LOW;
+ else
+ return EINVAL;
+ return 0;
}
+
void
erts_init_scheduling(int mrq, int no_schedulers, int no_schedulers_online)
@@ -7169,7 +7196,7 @@ Process *schedule(Process *p, int calls)
if (rq->wakeup_other < 0)
rq->wakeup_other = 0;
}
- else if (rq->wakeup_other < ERTS_WAKEUP_OTHER_LIMIT)
+ else if (rq->wakeup_other < wakeup_other_limit)
rq->wakeup_other += rq->len*wo_reds + ERTS_WAKEUP_OTHER_FIXED_INC;
else {
if (erts_common_run_queue) {
diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h
index e49710a7ed..4365e409e5 100644
--- a/erts/emulator/beam/erl_process.h
+++ b/erts/emulator/beam/erl_process.h
@@ -1038,6 +1038,8 @@ ErtsProcList *erts_proclist_create(Process *);
void erts_proclist_destroy(ErtsProcList *);
int erts_proclist_same(ErtsProcList *, Process *);
+int erts_sched_set_wakeup_limit(char *str);
+
#ifdef DEBUG
void erts_dbg_multi_scheduling_return_trap(Process *, Eterm);
#endif
diff --git a/erts/etc/common/erlexec.c b/erts/etc/common/erlexec.c
index 76ce0a7e3c..c1fc2aebee 100644
--- a/erts/etc/common/erlexec.c
+++ b/erts/etc/common/erlexec.c
@@ -120,6 +120,7 @@ static char *plusM_other_switches[] = {
static char *pluss_val_switches[] = {
"bt",
"ct",
+ "wt",
"ss",
NULL
};
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