MessagePumpForGpu - reduce potential work processing starvation

base/message_loop/message_pump_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/message_loop/message_pump_win.h"
 
 #include <math.h>
 #include <stdint.h>
 
 #include <limits>
@@ skipping 431 matching lines @@
 
 // static
 std::unique_ptr<MessagePump> MessagePumpForGpu::CreateMessagePumpForGpu() {
   return WrapUnique<MessagePump>(new MessagePumpForGpu);
 }
 
 void MessagePumpForGpu::ScheduleWork() {
   if (InterlockedExchange(&work_state_, HAVE_WORK) != READY)
     return;  // Someone else continued the pumping.
 
+  // TODO(stanisc): crbug.com/596190: Preserve for crash dump analysis.
+  // Remove this when the bug is fixes.

[brucedawson, 2016/06/03 23:36:15]

fixes -> fixed

+  last_set_event_timeticks_ = TimeTicks::Now();
+
   // Make sure the MessagePump does some work for us.
   SetEvent(event_);
 }
 
 void MessagePumpForGpu::ScheduleDelayedWork(
     const TimeTicks& delayed_work_time) {
   // We know that we can't be blocked right now since this method can only be
   // called on the same thread as Run, so we only need to update our record of
   // how long to sleep when we do sleep.
   delayed_work_time_ = delayed_work_time;
@@ skipping 51 matching lines @@
   int delay;
 
   // The while loop handles the situation where on Windows 7 and later versions
   // MsgWaitForMultipleObjectsEx might time out slightly earlier (less than one
   // ms) than the specified |delay|. In that situation it is more optimal to
   // just wait again rather than waste a DoRunLoop cycle.
   while ((delay = GetCurrentDelay()) != 0) {
     if (delay < 0)  // Negative value means no timers waiting.
       delay = INFINITE;
 
+    // TODO(stanisc): crbug.com/596190: Preserve for crash dump analysis.
+    // Remove this when the bug is fixes.

[brucedawson, 2016/06/03 23:36:15]

fixes -> fixed

+    TimeTicks wait_for_work_timeticks = TimeTicks::Now();
+    debug::Alias(&wait_for_work_timeticks);
+    debug::Alias(&delay);
+
     DWORD result =
         MsgWaitForMultipleObjectsEx(1, &event_, delay, QS_ALLINPUT, 0);
-    if (result == WAIT_OBJECT_0) {
-      // Work available.
+    DCHECK_NE(WAIT_FAILED, result) << GetLastError();
+    if (result != WAIT_TIMEOUT) {
+      // Either work or message available.
       return;
-    } else if (result == WAIT_OBJECT_0 + 1) {
-      // Message available. Keep waiting if this message isn't for this thread.
-      MSG msg;
-      if (PeekMessage(&msg, nullptr, 0, 0, PM_NOREMOVE))
-        return;
     }
-
-    DCHECK_NE(WAIT_FAILED, result) << GetLastError();
   }
 }
 
 bool MessagePumpForGpu::ProcessNextMessage() {
   MSG msg;
   if (!PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE))
     return false;
 
   if (msg.message == WM_QUIT) {
     // Repost the QUIT message so that it will be retrieved by the primary
@@ skipping 182 matching lines @@
     if (!filter || it->handler == filter) {
       *item = *it;
       completed_io_.erase(it);
       return true;
     }
   }
   return false;
 }
 
 }  // namespace base