aboutsummaryrefslogtreecommitdiffstats
path: root/erts/emulator/beam/erl_process.c
diff options
context:
space:
mode:
authorRickard Green <[email protected]>2013-06-11 17:30:47 +0200
committerFredrik Gustafsson <[email protected]>2013-09-16 13:57:15 +0200
commit90351e1167a3bf21c2378306b68f560601e8415f (patch)
tree6824168cb5b70be26e3ebd929e679aa70cb3117c /erts/emulator/beam/erl_process.c
parentc72b20183a780c7199d3959f09eb88c1a930a064 (diff)
downloadotp-90351e1167a3bf21c2378306b68f560601e8415f.tar.gz
otp-90351e1167a3bf21c2378306b68f560601e8415f.tar.bz2
otp-90351e1167a3bf21c2378306b68f560601e8415f.zip
erts: Add the +sfwi system flag
+sfwi Interval Set scheduler forced wakeup interval. All run queues will be scanned each Interval milliseconds. While there are sleeping schedulers in the system, one scheduler will be woken for each non-empty run queue found. An Interval of zero disables this feature, which also is the default. This feature has been introduced as a temporary workaround for lengthy executing native code, and native code that do not bump reductions properly in OTP. When these bugs have be fixed the +sfwi flag will be removed. Conflicts: erts/doc/src/erl.xml erts/etc/common/erlexec.c
Diffstat (limited to 'erts/emulator/beam/erl_process.c')
-rw-r--r--erts/emulator/beam/erl_process.c85
1 files changed, 82 insertions, 3 deletions
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 9425fa7088..b84b5b39a5 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -218,6 +218,10 @@ static erts_smp_atomic32_t function_calls;
#ifdef ERTS_SMP
static erts_smp_atomic32_t doing_sys_schedule;
static erts_smp_atomic32_t no_empty_run_queues;
+long erts_runq_supervision_interval = 0;
+static ethr_event runq_supervision_event;
+static erts_tid_t runq_supervisor_tid;
+static erts_atomic_t runq_supervisor_sleeping;
#else /* !ERTS_SMP */
ErtsSchedulerData *erts_scheduler_data;
#endif
@@ -1885,7 +1889,13 @@ empty_runq(ErtsRunQueue *rq)
*/
ASSERT(0 <= empty && empty < 2*erts_no_run_queues);
#endif
- erts_smp_atomic32_inc_relb(&no_empty_run_queues);
+ if (!erts_runq_supervision_interval)
+ erts_smp_atomic32_inc_relb(&no_empty_run_queues);
+ else {
+ erts_smp_atomic32_inc_mb(&no_empty_run_queues);
+ if (erts_atomic_read_nob(&runq_supervisor_sleeping))
+ ethr_event_set(&runq_supervision_event);
+ }
}
}
@@ -1903,7 +1913,14 @@ non_empty_runq(ErtsRunQueue *rq)
*/
ASSERT(0 < empty && empty <= 2*erts_no_run_queues);
#endif
- erts_smp_atomic32_dec_relb(&no_empty_run_queues);
+ if (!erts_runq_supervision_interval)
+ erts_smp_atomic32_dec_relb(&no_empty_run_queues);
+ else {
+ erts_aint32_t no;
+ no = erts_smp_atomic32_dec_read_mb(&no_empty_run_queues);
+ if (no > 0 && erts_atomic_read_nob(&runq_supervisor_sleeping))
+ ethr_event_set(&runq_supervision_event);
+ }
}
}
@@ -2505,7 +2522,6 @@ try_inc_no_active_runqs(int active)
return 0;
}
-
static ERTS_INLINE int
chk_wake_sched(ErtsRunQueue *crq, int ix, int activate)
{
@@ -3829,6 +3845,53 @@ set_wakeup_other_data(void)
}
}
+static int
+no_runqs_to_supervise(void)
+{
+ int used;
+ erts_aint32_t nerq = erts_smp_atomic32_read_acqb(&no_empty_run_queues);
+ if (nerq <= 0)
+ return 0;
+ get_no_runqs(NULL, &used);
+ if (nerq >= used)
+ return 0;
+ return used;
+}
+
+static void *
+runq_supervisor(void *unused)
+{
+ while (1) {
+ int ix, no_rqs;
+
+ erts_milli_sleep(erts_runq_supervision_interval);
+ no_rqs = no_runqs_to_supervise();
+ if (!no_rqs) {
+ erts_atomic_set_nob(&runq_supervisor_sleeping, 1);
+ while (1) {
+ ethr_event_reset(&runq_supervision_event);
+ no_rqs = no_runqs_to_supervise();
+ if (no_rqs) {
+ erts_atomic_set_nob(&runq_supervisor_sleeping, 0);
+ break;
+ }
+ ethr_event_wait(&runq_supervision_event);
+ }
+ }
+
+ for (ix = 0; ix < no_rqs; ix++) {
+ ErtsRunQueue *rq = ERTS_RUNQ_IX(ix);
+ if (ERTS_RUNQ_FLGS_GET(rq) & ERTS_RUNQ_FLG_NONEMPTY) {
+ erts_smp_runq_lock(rq);
+ if (rq->len != 0)
+ wake_scheduler_on_empty_runq(rq); /* forced wakeup... */
+ erts_smp_runq_unlock(rq);
+ }
+ }
+ }
+ return NULL;
+}
+
#endif
void
@@ -5235,6 +5298,22 @@ erts_start_schedulers(void)
ethr_thr_opts opts = ETHR_THR_OPTS_DEFAULT_INITER;
opts.detached = 1;
+
+#ifdef ERTS_SMP
+ if (erts_runq_supervision_interval) {
+ opts.suggested_stack_size = 16;
+ erts_atomic_init_nob(&runq_supervisor_sleeping, 0);
+ if (0 != ethr_event_init(&runq_supervision_event))
+ erl_exit(1, "Failed to create run-queue supervision event\n");
+ if (0 != ethr_thr_create(&runq_supervisor_tid,
+ runq_supervisor,
+ NULL,
+ &opts))
+ erl_exit(1, "Failed to create run-queue supervision thread\n");
+
+ }
+#endif
+
opts.suggested_stack_size = erts_sched_thread_suggested_stack_size;
if (wanted < 1)