net: Add some metrics on reuse of idle sockets.

net/socket/client_socket_pool_base.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 "net/socket/client_socket_pool_base.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/compiler_specific.h"
 #include "base/format_macros.h"
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "base/values.h"
 #include "net/base/net_errors.h"
 #include "net/log/net_log.h"
 
@@ skipping 944 matching lines @@
     base::TimeDelta idle_time,
     Group* group,
     const BoundNetLog& net_log) {
   DCHECK(socket);
   handle->SetSocket(std::move(socket));
   handle->set_reuse_type(reuse_type);
   handle->set_idle_time(idle_time);
   handle->set_pool_id(pool_generation_number_);
   handle->set_connect_timing(connect_timing);
 
-  if (handle->is_reused()) {
+  if (reuse_type == ClientSocketHandle::REUSED_IDLE) {
     net_log.AddEvent(
         NetLog::TYPE_SOCKET_POOL_REUSED_AN_EXISTING_SOCKET,
         NetLog::IntCallback("idle_ms",
                             static_cast<int>(idle_time.InMilliseconds())));
+
+    UMA_HISTOGRAM_COUNTS_1000("Net.Socket.IdleSocketReuseTime",
+                              idle_time.InSeconds());
+  }
+
+  if (reuse_type != ClientSocketHandle::UNUSED) {
+    // The socket being handed out is no longer considered idle, but was
+    // considered idle until just before this method was called.
+    UMA_HISTOGRAM_CUSTOM_COUNTS("Net.Socket.NumIdleSockets",
+                                idle_socket_count() + 1, 1, 256, 50);
   }
 
   net_log.AddEvent(
       NetLog::TYPE_SOCKET_POOL_BOUND_TO_SOCKET,
       handle->socket()->NetLog().source().ToEventParametersCallback());
 
   handed_out_socket_count_++;
   group->IncrementActiveSocketCount();
 }
 
@@ skipping 316 matching lines @@
   // If there are no more requests, kill the backup timer.
   if (pending_requests_.empty())
     backup_job_timer_.Stop();
   request->CrashIfInvalid();
   return request;
 }
 
 }  // namespace internal
 
 }  // namespace net