When a thread hints that it is in a spin-wait loop (eg, x86 REP NOP insn),

deschedule the thread much sooner (300 evchecks) than previously (1000
evchecks).  Once the thread is spinning, there's absolutely no point in
continuing with it, since only a different thread can get it out of the loop,
so we need to drop the current thread ASAP.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@16412

diff --git a/coregrind/m_scheduler/scheduler.c b/coregrind/m_scheduler/scheduler.c
index 7bc03f9aadf11c44b4e6575687778bf2910c7104..39f10f888238ffaf6b83a7f0f73d011a6f571e6a 100644 (file)
--- a/coregrind/m_scheduler/scheduler.c
+++ b/coregrind/m_scheduler/scheduler.c
@@ -1453,8 +1453,8 @@ VgSchedReturnCode VG_(scheduler) ( ThreadId tid )
             before swapping to another.  That means that short term
             spins waiting for hardware to poke memory won't cause a
             thread swap. */
-         if (dispatch_ctr > 1000)
-            dispatch_ctr = 1000;
+         if (dispatch_ctr > 300)
+            dispatch_ctr = 300;
         break;
 
       case VG_TRC_INNER_COUNTERZERO: