Fix MemoryBarrier

dotnet · Aug 10, 2016 · a0597da · a0597da
1 parent 519dcde
commit a0597da
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Showing 2 changed files with 6 additions and 6 deletions.
diff --git a/src/vm/win32threadpool.cpp b/src/vm/win32threadpool.cpp
@@ -1263,10 +1263,10 @@ void ThreadpoolMgr::AdjustMaxWorkersActive()
         }
 
         PriorCompletedWorkRequests = totalNumCompletions;
-        PriorCompletedWorkRequestsTime = currentTicks;
         NextCompletedWorkRequestsTime = currentTicks + ThreadAdjustmentInterval;
-        CurrentSampleStartTime = endTime;
-        MemoryBarrier();
+        MemoryBarrier(); // flush previous writes (especially NextCompletedWorkRequestsTime)
+        PriorCompletedWorkRequestsTime = currentTicks;
+        CurrentSampleStartTime = endTime;;
     }
 }
 

diff --git a/src/vm/win32threadpool.h b/src/vm/win32threadpool.h
@@ -1142,9 +1142,9 @@ class ThreadpoolMgr
         if (CLRThreadpoolHosted())
             return false;
 
-        MemoryBarrier();
-        DWORD priorTime = PriorCompletedWorkRequestsTime; 
-        DWORD requiredInterval = NextCompletedWorkRequestsTime - priorTime; // fences above read
+        DWORD priorTime = PriorCompletedWorkRequestsTime;
+        MemoryBarrier(); // read fresh value for NextCompletedWorkRequestsTime below
+        DWORD requiredInterval = NextCompletedWorkRequestsTime - priorTime;
         DWORD elapsedInterval = GetTickCount() - priorTime;
         if (elapsedInterval >= requiredInterval)
         {