Add a histogram to measure how long are we waiting to close...

net/base/tcp_client_socket_win.cc

 // Copyright (c) 2006-2008 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 "net/base/tcp_client_socket_win.h"
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory_debug.h"
 #include "base/string_util.h"
@@ skipping 139 matching lines @@
   // In most socket implementations, closing a socket results in a graceful
   // connection shutdown, but in Winsock we have to call shutdown explicitly.
   // See the MSDN page "Graceful Shutdown, Linger Options, and Socket Closure"
   // at http://msdn.microsoft.com/en-us/library/ms738547.aspx
   shutdown(socket_, SD_SEND);
 
   // This cancels any pending IO.
   closesocket(socket_);
   socket_ = INVALID_SOCKET;
 
-  // Wait for pending IO to be aborted.
-  if (waiting_read_)
-    WaitForSingleObject(read_overlapped_.hEvent, INFINITE);
-  if (waiting_write_)
-    WaitForSingleObject(write_overlapped_.hEvent, INFINITE);
+  if (waiting_read_ || waiting_write_) {
+    base::TimeTicks start = base::TimeTicks::Now();
+
+    // Wait for pending IO to be aborted.
+    if (waiting_read_)
+      WaitForSingleObject(read_overlapped_.hEvent, INFINITE);
+    if (waiting_write_)
+      WaitForSingleObject(write_overlapped_.hEvent, INFINITE);
+
+    // We want to see if we block the message loop for too long.
+    UMA_HISTOGRAM_TIMES("AsyncIO.ClientSocketDisconnect",
+                        base::TimeTicks::Now() - start);
+  }
 
   WSACloseEvent(read_overlapped_.hEvent);
   memset(&read_overlapped_, 0, sizeof(read_overlapped_));
   WSACloseEvent(write_overlapped_.hEvent);
   memset(&write_overlapped_, 0, sizeof(write_overlapped_));
 
   // Reset for next time.
   current_ai_ = addresses_.head();
 
   waiting_read_ = false;
@@ skipping 252 matching lines @@
       FALSE, &flags);
   WSAResetEvent(object);
   TRACE_EVENT_END("socket.write", tcp_socket_,
                   StringPrintf("%d bytes", num_bytes));
   tcp_socket_->waiting_write_ = false;
   tcp_socket_->DoWriteCallback(
       ok ? num_bytes : MapWinsockError(WSAGetLastError()));
 }
 
 }  // namespace net