erts: Add microstate accounting

Microstate accounting is a way to track which state the
different threads within ERTS are in. The main usage area
is to pin point performance bottlenecks by checking which
states the threads are in and then from there figuring out
why and where to optimize.

Since checking whether microstate accounting is on or off is
relatively expensive if done in a short loop only a few of the
states are enabled by default and more states can be enabled
through configure.

I've done some benchmarking and the overhead with it turned off
is not noticible and with it on it is a fraction of a percent.
If you enable the extra states, depending on the benchmark,
the ovehead when turned off is about 1% and when turned on
somewhere inbetween 5-15%.

OTP-12345

1 files changed, 18 insertions, 2 deletions

diff --git a/erts/emulator/beam/time.c b/erts/emulator/beam/time.c
index 0ab6661c9f..48cb39333a 100644
--- a/erts/emulator/beam/time.c
+++ b/erts/emulator/beam/time.c
@@ -278,9 +278,14 @@ ErtsMonotonicTime
 erts_check_next_timeout_time(ErtsSchedulerData *esdp)
 {
     ErtsTimerWheel *tiw = esdp->timer_wheel;
+    ErtsMonotonicTime time;
+    ERTS_MSACC_DECLARE_CACHE_X();
     if (tiw->true_next_timeout_time)
 	return tiw->next_timeout_time;
-    return find_next_timeout(esdp, tiw, 1, 0, 0);
+    ERTS_MSACC_PUSH_AND_SET_STATE_CACHED_X(ERTS_MSACC_STATE_TIMERS);
+    time = find_next_timeout(esdp, tiw, 1, 0, 0);
+    ERTS_MSACC_POP_STATE_M_X();
+    return time;
 }
 
 #ifndef ERTS_TW_DEBUG
@@ -336,6 +341,7 @@ erts_bump_timers(ErtsTimerWheel *tiw, ErtsMonotonicTime curr_time)
 {
     int tiw_pos_ix, slots, yielded_slot_restarted, yield_count;
     ErtsMonotonicTime bump_to, tmp_slots, old_pos;
+    ERTS_MSACC_PUSH_AND_SET_STATE_M_X(ERTS_MSACC_STATE_TIMERS);
 
     yield_count = ERTS_TWHEEL_BUMP_YIELD_LIMIT;
 
@@ -371,6 +377,7 @@ erts_bump_timers(ErtsTimerWheel *tiw, ErtsMonotonicTime curr_time)
 		tiw->next_timeout_time = curr_time + ERTS_MONOTONIC_DAY;
 		tiw->pos = bump_to;
 		tiw->yield_slot = ERTS_TWHEEL_SLOT_INACTIVE;
+                ERTS_MSACC_POP_STATE_M_X();
 		return;
 	    }
 
@@ -382,6 +389,7 @@ erts_bump_timers(ErtsTimerWheel *tiw, ErtsMonotonicTime curr_time)
 		    tiw->yield_slot = ERTS_TWHEEL_SLOT_AT_ONCE;
 		    tiw->true_next_timeout_time = 1;
 		    tiw->next_timeout_time = ERTS_CLKTCKS_TO_MONOTONIC(old_pos);
+                    ERTS_MSACC_POP_STATE_M_X();
 		    return;
 		}
 
@@ -400,8 +408,10 @@ erts_bump_timers(ErtsTimerWheel *tiw, ErtsMonotonicTime curr_time)
 		p = tiw->at_once.head;
 	    }
 
-	    if (tiw->pos >= bump_to)
+	    if (tiw->pos >= bump_to) {
+                ERTS_MSACC_POP_STATE_M_X();
 		break;
+            }
 
 	    if (tiw->nto == 0)
 		goto empty_wheel;
@@ -478,6 +488,7 @@ erts_bump_timers(ErtsTimerWheel *tiw, ErtsMonotonicTime curr_time)
 			    tiw->yield_slot = tiw_pos_ix;
 			    tiw->yield_slots_left = slots;
 			    tiw->yield_start_pos = old_pos;
+                            ERTS_MSACC_POP_STATE_M_X();
 			    return; /* Yield! */
 			}
 
@@ -500,6 +511,7 @@ erts_bump_timers(ErtsTimerWheel *tiw, ErtsMonotonicTime curr_time)
 
     /* Search at most two seconds ahead... */
     (void) find_next_timeout(NULL, tiw, 0, curr_time, ERTS_SEC_TO_MONOTONIC(2));
+    ERTS_MSACC_POP_STATE_M_X();
 }
 
 Uint
@@ -569,6 +581,7 @@ erts_twheel_set_timer(ErtsTimerWheel *tiw,
 		      ErtsMonotonicTime timeout_pos)
 {
     ErtsMonotonicTime timeout_time;
+    ERTS_MSACC_PUSH_AND_SET_STATE_M_X(ERTS_MSACC_STATE_TIMERS);
 
     p->u.func.timeout = timeout;
     p->u.func.cancel = cancel;
@@ -612,6 +625,7 @@ erts_twheel_set_timer(ErtsTimerWheel *tiw,
 	tiw->true_next_timeout_time = 1;
 	tiw->next_timeout_time = timeout_time;
     }
+    ERTS_MSACC_POP_STATE_M_X();
 }
 
 void
@@ -620,11 +634,13 @@ erts_twheel_cancel_timer(ErtsTimerWheel *tiw, ErtsTWheelTimer *p)
     if (p->slot != ERTS_TWHEEL_SLOT_INACTIVE) {
 	ErlCancelProc cancel;
 	void *arg;
+        ERTS_MSACC_PUSH_AND_SET_STATE_M_X(ERTS_MSACC_STATE_TIMERS);
 	remove_timer(tiw, p);
 	cancel = p->u.func.cancel;
 	arg = p->u.func.arg;
 	if (cancel)
 	    (*cancel)(arg);
+        ERTS_MSACC_POP_STATE_M_X();
     }
 }