Experiment for number of persistent connections to server

Currently Chrome, Firefox, and IE8 have the number of outgoing connections to each host(server) set at 6.
 Safari uses 4, and Fasterfox (a plugin for Firefox that supposedly
 configures it to run faster) uses 8. We would like to see how much of an
 effect this value has on browsing. Too large a value might cause us to
 run into SYN flood detection mechanisms. This experiment assigns a value of (4, 6, 8, 16) at random at program launch, and uses it throughout the run.

r=jar


Review URL: http://codereview.chromium.org/2685005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@49057 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 12 insertions, 0 deletions

diff --git a/net/http/http_network_transaction.cc b/net/http/http_network_transaction.cc
index db67c13..d5361ce 100644
--- a/net/http/http_network_transaction.cc
+++ b/net/http/http_network_transaction.cc
@@ -1598,6 +1598,18 @@ void HttpNetworkTransaction::LogTransactionConnectedMetrics() const {
         total_duration,
         base::TimeDelta::FromMilliseconds(1), base::TimeDelta::FromMinutes(10),
         100);
+
+  static bool use_conn_impact_histogram(
+      FieldTrialList::Find("ConnCountImpact") &&
+      !FieldTrialList::Find("ConnCountImpact")->group_name().empty());
+  if (use_conn_impact_histogram) {
+    UMA_HISTOGRAM_CLIPPED_TIMES(
+        FieldTrial::MakeName("Net.Transaction_Connected_New",
+            "ConnCountImpact"),
+        total_duration,
+        base::TimeDelta::FromMilliseconds(1), base::TimeDelta::FromMinutes(10),
+        100);
+    }
   }
 
   // Currently, non-zero priority requests are frame or sub-frame resource