Merge branch 'wip/tsan/timer' into wip/tsan/all

1 files changed, 13 insertions, 11 deletions

diff --git a/rts/Timer.c b/rts/Timer.c
index 990eba6b05..97d87ad989 100644
--- a/rts/Timer.c
+++ b/rts/Timer.c
@@ -25,6 +25,15 @@
 #include "Capability.h"
 #include "RtsSignals.h"
 
+// This global counter is used to allow multiple threads to stop the
+// timer temporarily with a stopTimer()/startTimer() pair.  If
+//      timer_enabled  == 0          timer is enabled
+//      timer_disabled == N, N > 0   timer is disabled by N threads
+// When timer_enabled makes a transition to 0, we enable the timer,
+// and when it makes a transition to non-0 we disable it.
+
+static StgWord timer_disabled;
+
 /* ticks left before next pre-emptive context switch */
 static int ticks_to_ctxt_switch = 0;
 
@@ -92,7 +101,9 @@ void
 handle_tick(int unused STG_UNUSED)
 {
   handleProfTick();
-  if (RtsFlags.ConcFlags.ctxtSwitchTicks > 0) {
+  if (RtsFlags.ConcFlags.ctxtSwitchTicks > 0
+      && SEQ_CST_LOAD(&timer_disabled) == 0)
+  {
       ticks_to_ctxt_switch--;
       if (ticks_to_ctxt_switch <= 0) {
           ticks_to_ctxt_switch = RtsFlags.ConcFlags.ctxtSwitchTicks;
@@ -148,15 +159,6 @@ handle_tick(int unused STG_UNUSED)
   }
 }
 
-// This global counter is used to allow multiple threads to stop the
-// timer temporarily with a stopTimer()/startTimer() pair.  If
-//      timer_enabled  == 0          timer is enabled
-//      timer_disabled == N, N > 0   timer is disabled by N threads
-// When timer_enabled makes a transition to 0, we enable the timer,
-// and when it makes a transition to non-0 we disable it.
-
-static StgWord timer_disabled;
-
 void
 initTimer(void)
 {
@@ -164,7 +166,7 @@ initTimer(void)
     if (RtsFlags.MiscFlags.tickInterval != 0) {
         initTicker(RtsFlags.MiscFlags.tickInterval, handle_tick);
     }
-    timer_disabled = 1;
+    SEQ_CST_STORE(&timer_disabled, 1);
 }
 
 void