Changeset 9235 for trunk/src/kernel32/HandleManager.cpp

Timestamp:

Sep 14, 2002, 3:49:39 PM (23 years ago)

Author:

sandervl

Message:

WaitForSingleObject, (Msg)WaitForMultipleObjects: If dwTimeout is not 0 and smaller than 20 ms, then temporarily change thread priority to time critical to make sure we don't get a late timeout

File:

• trunk/src/kernel32/HandleManager.cpp (modified) (6 diffs)

trunk/src/kernel32/HandleManager.cpp

@@ -1 @@
-/* $Id: HandleManager.cpp,v 1.90 2002-08-01 16:02:40 sandervl Exp $ */
+/* $Id: HandleManager.cpp,v 1.91 2002-09-14 13:49:39 sandervl Exp $ */
 
 /*
@@ -1982 +1982 @@
   }
 
+  //If the timeout is less than 20 milliseconds (and not zero), then we are likely to
+  //return too late if the thread priority isn't time critical (time slices
+  //of 32 ms)
+  //To avoid this problem, we temporarily switch to time critical priority.
+  HANDLE hThread          = GetCurrentThread();
+  DWORD  dwThreadPriority = GetThreadPriority(hThread);
+
+  if(dwTimeout && dwTimeout < 20 && dwThreadPriority != THREAD_PRIORITY_TIME_CRITICAL) {
+      dprintf(("Temporarily change priority to THREAD_PRIORITY_TIME_CRITICAL for better timing"));
+      SetThreadPriority(hThread, THREAD_PRIORITY_TIME_CRITICAL);
+      //round to 8 ms units to get more precise timeouts
+      if(dwTimeout > 8)
+          dwTimeout = (dwTimeout/8)*8;
+  }
+  else dwThreadPriority = -1;
+
   pHMHandle = &TabWin32Handles[iIndex];               /* call device handler */
   dwResult = pHMHandle->pDeviceHandler->WaitForSingleObject(&pHMHandle->hmHandleData,
                                                             dwTimeout);
 
+  //Restore thread priority if we previously changed it
+  if(dwThreadPriority != -1) {
+      SetThreadPriority(hThread, dwThreadPriority);
+  }
   return (dwResult);                                  /* deliver return code */
 }
@@ -2982 +3002 @@
   }
 
+  //If the timeout is less than 20 milliseconds (and not zero), then we are likely to
+  //return too late if the thread priority isn't time critical (time slices
+  //of 32 ms)
+  //To avoid this problem, we temporarily switch to time critical priority.
+  HANDLE hThread          = GetCurrentThread();
+  DWORD  dwThreadPriority = GetThreadPriority(hThread);
+
+  if(dwTimeout && dwTimeout < 20 && dwThreadPriority != THREAD_PRIORITY_TIME_CRITICAL) {
+      dprintf(("Temporarily change priority to THREAD_PRIORITY_TIME_CRITICAL for better timing"));
+      SetThreadPriority(hThread, THREAD_PRIORITY_TIME_CRITICAL);
+      //round to 8 ms units to get more precise timeouts
+      if(dwTimeout > 8)
+          dwTimeout = (dwTimeout/8)*8;
+  }
+  else dwThreadPriority = -1;
+
   // OK, now forward to Open32.
   // @@@PH: Note this will fail on handles that do NOT belong to Open32
@@ -2990 +3026 @@
                                   dwTimeout);
 
+  //Restore old thread priority if we changed it before
+  if(dwThreadPriority != -1) {
+      SetThreadPriority(hThread, dwThreadPriority);
+  }
+
   return (rc);                            // OK, done
 #endif
@@ -3112 +3153 @@
   }
 
+  //If the timeout is less than 20 milliseconds (and not zero), then we are likely to
+  //return too late if the thread priority isn't time critical (time slices
+  //of 32 ms)
+  //To avoid this problem, we temporarily switch to time critical priority.
+  HANDLE hThread          = GetCurrentThread();
+  DWORD  dwThreadPriority = GetThreadPriority(hThread);
+
+  if(dwTimeout && dwTimeout < 20 && dwThreadPriority != THREAD_PRIORITY_TIME_CRITICAL) {
+      dprintf(("Temporarily change priority to THREAD_PRIORITY_TIME_CRITICAL for better timing"));
+      SetThreadPriority(hThread, THREAD_PRIORITY_TIME_CRITICAL);
+      //round to 8 ms units to get more precise timeouts
+      if(dwTimeout > 8)
+          dwTimeout = (dwTimeout/8)*8;
+  }
+  else dwThreadPriority = -1;
+
   // OK, now forward to Open32.
   // @@@PH: Note this will fail on handles that do NOT belong to Open32
@@ -3119 +3176 @@
                                      fWaitAll, dwTimeout,
                                      dwWakeMask);
+
+  //Restore old thread priority if we changed it before
+  if(dwThreadPriority != -1) {
+      SetThreadPriority(hThread, dwThreadPriority);
+  }
 
   dprintf2(("MsgWaitForMultipleObjects returned %d", rc));