Added histograms to see if the interval between consecutive connects has

an impact on connect time.

R=jar@chromium.org
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=227233

Review URL: https://codereview.chromium.org/26098002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227306 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 46 insertions, 1 deletions

diff --git a/net/socket/transport_client_socket_pool.cc b/net/socket/transport_client_socket_pool.cc
index d03e3e6..6da3b45 100644
--- a/net/socket/transport_client_socket_pool.cc
+++ b/net/socket/transport_client_socket_pool.cc
@@ -7,10 +7,12 @@
 #include <algorithm>
 
 #include "base/compiler_specific.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_util.h"
+#include "base/synchronization/lock.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "net/base/ip_endpoint.h"
@@ -46,6 +48,14 @@ bool AddressListOnlyContainsIPv6(const AddressList& list) {
 
 }  // namespace
 
+// This lock protects |g_last_connect_time|.
+static base::LazyInstance<base::Lock>::Leaky
+    g_last_connect_time_lock = LAZY_INSTANCE_INITIALIZER;
+
+// |g_last_connect_time| has the last time a connect() call is made.
+static base::LazyInstance<base::TimeTicks>::Leaky
+    g_last_connect_time = LAZY_INSTANCE_INITIALIZER;
+
 TransportSocketParams::TransportSocketParams(
     const HostPortPair& host_port_pair,
     bool disable_resolver_cache,
@@ -85,7 +95,8 @@ TransportConnectJob::TransportConnectJob(
       params_(params),
       client_socket_factory_(client_socket_factory),
       resolver_(host_resolver),
-      next_state_(STATE_NONE) {
+      next_state_(STATE_NONE),
+      less_than_20ms_since_connect_(true) {
 }
 
 TransportConnectJob::~TransportConnectJob() {
@@ -186,6 +197,20 @@ int TransportConnectJob::DoResolveHostComplete(int result) {
 }
 
 int TransportConnectJob::DoTransportConnect() {
+  base::TimeTicks now = base::TimeTicks::Now();
+  base::TimeTicks last_connect_time;
+  {
+    base::AutoLock lock(g_last_connect_time_lock.Get());
+    last_connect_time = g_last_connect_time.Get();
+    *g_last_connect_time.Pointer() = now;
+  }
+  if (last_connect_time.is_null() ||
+      (now - last_connect_time).InMilliseconds() < 20) {
+    less_than_20ms_since_connect_ = true;
+  } else {
+    less_than_20ms_since_connect_ = false;
+  }
+
   next_state_ = STATE_TRANSPORT_CONNECT_COMPLETE;
   transport_socket_ = client_socket_factory_->CreateTransportClientSocket(
         addresses_, net_log().net_log(), net_log().source());
@@ -222,6 +247,22 @@ int TransportConnectJob::DoTransportConnectComplete(int result) {
         base::TimeDelta::FromMinutes(10),
         100);
 
+    if (less_than_20ms_since_connect_) {
+      UMA_HISTOGRAM_CUSTOM_TIMES(
+          "Net.TCP_Connection_Latency_Interval_20ms_Minus",
+          connect_duration,
+          base::TimeDelta::FromMilliseconds(1),
+          base::TimeDelta::FromMinutes(10),
+          100);
+    } else {
+      UMA_HISTOGRAM_CUSTOM_TIMES(
+          "Net.TCP_Connection_Latency_Interval_20ms_Plus",
+          connect_duration,
+          base::TimeDelta::FromMilliseconds(1),
+          base::TimeDelta::FromMinutes(10),
+          100);
+    }
+
     if (is_ipv4) {
       UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency_IPv4_No_Race",
                                  connect_duration,
diff --git a/net/socket/transport_client_socket_pool.h b/net/socket/transport_client_socket_pool.h
index 16e421a..95b51c3 100644
--- a/net/socket/transport_client_socket_pool.h
+++ b/net/socket/transport_client_socket_pool.h
@@ -125,6 +125,10 @@ class NET_EXPORT_PRIVATE TransportConnectJob : public ConnectJob {
   base::TimeTicks fallback_connect_start_time_;
   base::OneShotTimer<TransportConnectJob> fallback_timer_;
 
+  // If the interval between this connect and previous connect is less than
+  // 20ms, then |less_than_20ms_since_connect_| is set to true.
+  bool less_than_20ms_since_connect_;
+
   DISALLOW_COPY_AND_ASSIGN(TransportConnectJob);
 };