? threads/.gdb_history
Index: threads/nsThread.cpp
===================================================================
RCS file: /cvsroot/mozilla/xpcom/threads/nsThread.cpp,v
retrieving revision 1.70
diff -u -p -5 -r1.70 nsThread.cpp
--- threads/nsThread.cpp	11 Jul 2007 03:01:56 -0000	1.70
+++ threads/nsThread.cpp	25 Aug 2007 15:53:36 -0000
@@ -229,10 +229,15 @@ private:
   nsThreadShutdownContext *mShutdownContext;
 };
 
 //-----------------------------------------------------------------------------
 
+// number of latency entries in the buffer before we dump to stderr
+#define LATENCY_BUFFER_COUNT 1000
+// below this threshold, we don't bother logging the latency
+#define LATENCY_IGNORE_BELOW 10
+
 /*static*/ void
 nsThread::ThreadFunc(void *arg)
 {
   nsThread *self = static_cast<nsThread *>(arg);  // strong reference
   self->mThread = PR_GetCurrentThread();
@@ -248,10 +253,11 @@ nsThread::ThreadFunc(void *arg)
   }
   event->Run();  // unblocks nsThread::Init
   event = nsnull;
 
   // Now, process incoming events...
+  self->mLastServiced = PR_IntervalNow();
   while (!self->ShuttingDown())
     NS_ProcessNextEvent(self);
 
   NS_ProcessPendingEvents(self);
 
@@ -273,17 +279,25 @@ nsThread::nsThread()
   , mPriority(PRIORITY_NORMAL)
   , mThread(nsnull)
   , mRunningEvent(0)
   , mShutdownContext(nsnull)
   , mShutdownRequired(PR_FALSE)
+  , mLatencies(0)
+  , mLatencyIndex(0)
 {
 }
 
 nsThread::~nsThread()
 {
   if (mLock)
     PR_DestroyLock(mLock);
+  if (mLatencies) {
+    for (int i = 0; i < mLatencyIndex; i++) {
+      fprintf(stderr, "[LAT] %d\n", PR_IntervalToMilliseconds(mLatencies[i]));
+    }
+    free(mLatencies);
+  }
 }
 
 nsresult
 nsThread::Init()
 {
@@ -323,10 +337,14 @@ nsThread::Init()
 nsresult
 nsThread::InitCurrentThread()
 {
   NS_ENSURE_TRUE(mLock, NS_ERROR_OUT_OF_MEMORY);
 
+  mLatencies = (PRIntervalTime *)malloc(sizeof(PRIntervalTime) * LATENCY_BUFFER_COUNT);
+  NS_ENSURE_TRUE(mLatencies, NS_ERROR_OUT_OF_MEMORY);
+  fprintf(stderr, "[%p] Latency buffer: %d\n", (void *)this, LATENCY_BUFFER_COUNT);
+
   mThread = PR_GetCurrentThread();
 
   nsThreadManager::get()->RegisterCurrentThread(this);
   return NS_OK;
 }
@@ -476,12 +494,24 @@ nsThread::ProcessNextEvent(PRBool mayWai
   if (obs)
     obs->OnProcessNextEvent(this, mayWait && !ShuttingDown(), mRunningEvent);
 
   // If we are shutting down, then do not wait for new events.
   nsCOMPtr<nsIRunnable> event; 
+  if (mLatencies) {
+    PRIntervalTime latency = PR_IntervalNow() - mLastServiced;
+    if (latency >= LATENCY_IGNORE_BELOW) {
+      mLatencies[mLatencyIndex++] = latency;
+      if (mLatencyIndex == LATENCY_BUFFER_COUNT) {
+        for (int i = 0; i < LATENCY_BUFFER_COUNT; i++) {
+          fprintf(stderr, "[LAT] %d\n", PR_IntervalToMilliseconds(mLatencies[i]));
+        }
+        mLatencyIndex = 0;
+      }
+    }
+  }
   mEvents->GetEvent(mayWait && !ShuttingDown(), getter_AddRefs(event));
-
+  mLastServiced = PR_IntervalNow();
   *result = (event.get() != nsnull);
 
   nsresult rv = NS_OK;
 
   if (event) {
Index: threads/nsThread.h
===================================================================
RCS file: /cvsroot/mozilla/xpcom/threads/nsThread.h,v
retrieving revision 1.27
diff -u -p -5 -r1.27 nsThread.h
--- threads/nsThread.h	11 Jul 2007 00:57:17 -0000	1.27
+++ threads/nsThread.h	25 Aug 2007 15:53:36 -0000
@@ -138,10 +138,13 @@ private:
 
   struct nsThreadShutdownContext *mShutdownContext;
 
   PRPackedBool mShutdownRequired;
   PRPackedBool mShutdownPending;
+  PRIntervalTime *mLatencies;
+  PRIntervalTime mLastServiced;
+  int            mLatencyIndex;
 };
 
 //-----------------------------------------------------------------------------
 
 class nsThreadSyncDispatch : public nsRunnable {