Experiment for number of persistent connections per host...

chrome/browser/browser_main.cc

 // Copyright (c) 2010 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 "chrome/browser/browser_main.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 161 matching lines @@
   PostEarlyInitialization();
 }
 
 // This is an A/B test for the maximum number of persistent connections per
 // host. Currently Chrome, Firefox, and IE8 have this value 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.
 void BrowserMainParts::ConnectionFieldTrial() {
-  const FieldTrial::Probability kConnDivisor = 100;
-  const FieldTrial::Probability kConn16 = 10;  // 10% probability
-  const FieldTrial::Probability kRemainingConn = 30;  // 30% probability
+  const FieldTrial::Probability kConnectDivisor = 100;
+  const FieldTrial::Probability kConnectProbability = 20;  // 20% probability
 
-  scoped_refptr<FieldTrial> conn_trial =
-      new FieldTrial("ConnCountImpact", kConnDivisor);
+  scoped_refptr<FieldTrial> connect_trial =
+      new FieldTrial("ConnCountImpact", kConnectDivisor);
 
-  const int conn_16 = conn_trial->AppendGroup("_conn_count_16", kConn16);
-  const int conn_4 = conn_trial->AppendGroup("_conn_count_4", kRemainingConn);
-  const int conn_8 = conn_trial->AppendGroup("_conn_count_8", kRemainingConn);
-  const int conn_6 = conn_trial->AppendGroup("_conn_count_6",
+  const int connect_5 = connect_trial->AppendGroup("_conn_count_5",
+                                                   kConnectProbability);
+  const int connect_6 = connect_trial->AppendGroup("_conn_count_6",
+                                                   kConnectProbability);
+  const int connect_7 = connect_trial->AppendGroup("_conn_count_7",
+                                                   kConnectProbability);
+  const int connect_8 = connect_trial->AppendGroup("_conn_count_8",
+                                                   kConnectProbability);
+  const int connect_9 = connect_trial->AppendGroup("_conn_count_9",
       FieldTrial::kAllRemainingProbability);
 
-  const int conn_trial_grp = conn_trial->group();
+  const int connect_trial_group = connect_trial->group();
 
-  if (conn_trial_grp == conn_4) {
-    net::HttpNetworkSession::set_max_sockets_per_group(4);
-  } else if (conn_trial_grp == conn_6) {
+  if (connect_trial_group == connect_5) {
+    net::HttpNetworkSession::set_max_sockets_per_group(5);
+  } else if (connect_trial_group == connect_6) {
     // This (6) is the current default value.
     net::HttpNetworkSession::set_max_sockets_per_group(6);
-  } else if (conn_trial_grp == conn_8) {
+  } else if (connect_trial_group == connect_7) {
+    net::HttpNetworkSession::set_max_sockets_per_group(7);
+  } else if (connect_trial_group == connect_8) {
     net::HttpNetworkSession::set_max_sockets_per_group(8);
-  } else if (conn_trial_grp == conn_16) {
-    net::HttpNetworkSession::set_max_sockets_per_group(16);
+  } else if (connect_trial_group == connect_9) {
+    net::HttpNetworkSession::set_max_sockets_per_group(9);
   } else {
     NOTREACHED();
   }
 }
 
 // A/B test for determining a value for unused socket timeout. Currently the
 // timeout defaults to 10 seconds. Having this value set too low won't allow us
 // to take advantage of idle sockets. Setting it to too high could possibly
 // result in more ERR_CONNECT_RESETs, requiring one RTT to receive the RST
 // packet and possibly another RTT to re-establish the connection.
 void BrowserMainParts::SocketTimeoutFieldTrial() {
-  const FieldTrial::Probability kIdleSktToDivisor = 100;  // Idle socket timeout
-  const FieldTrial::Probability kSktToProb = 25;  // 25% probability
+  const FieldTrial::Probability kIdleSocketTimeoutDivisor = 100;
+  // 25% probability
+  const FieldTrial::Probability kSocketTimeoutProbability = 25;
 
   scoped_refptr<FieldTrial> socket_timeout_trial =
-      new FieldTrial("IdleSktToImpact", kIdleSktToDivisor);
+      new FieldTrial("IdleSktToImpact", kIdleSocketTimeoutDivisor);
 
   const int socket_timeout_5 =
-      socket_timeout_trial->AppendGroup("_idle_timeout_5", kSktToProb);
+      socket_timeout_trial->AppendGroup("_idle_timeout_5",
+                                        kSocketTimeoutProbability);
   const int socket_timeout_10 =
-      socket_timeout_trial->AppendGroup("_idle_timeout_10", kSktToProb);
+      socket_timeout_trial->AppendGroup("_idle_timeout_10",
+                                        kSocketTimeoutProbability);
   const int socket_timeout_20 =
-      socket_timeout_trial->AppendGroup("_idle_timeout_20", kSktToProb);
+      socket_timeout_trial->AppendGroup("_idle_timeout_20",
+                                        kSocketTimeoutProbability);
   const int socket_timeout_60 =
       socket_timeout_trial->AppendGroup("_idle_timeout_60",
                                         FieldTrial::kAllRemainingProbability);
 
-  const int idle_to_trial_grp = socket_timeout_trial->group();
+  const int idle_to_trial_group = socket_timeout_trial->group();
 
-  if (idle_to_trial_grp == socket_timeout_5) {
+  if (idle_to_trial_group == socket_timeout_5) {
     net::ClientSocketPool::set_unused_idle_socket_timeout(5);
-  } else if (idle_to_trial_grp == socket_timeout_10) {
+  } else if (idle_to_trial_group == socket_timeout_10) {
     // This (10 seconds) is the current default value.
     net::ClientSocketPool::set_unused_idle_socket_timeout(10);
-  } else if (idle_to_trial_grp == socket_timeout_20) {
+  } else if (idle_to_trial_group == socket_timeout_20) {
     net::ClientSocketPool::set_unused_idle_socket_timeout(20);
-  } else if (idle_to_trial_grp == socket_timeout_60) {
+  } else if (idle_to_trial_group == socket_timeout_60) {
     net::ClientSocketPool::set_unused_idle_socket_timeout(60);
   } else {
     NOTREACHED();
   }
 }
 
 // When --use-spdy not set, users will be in A/B test for spdy.
 // group A (npn_with_spdy): this means npn and spdy are enabled. In case server
 //                          supports spdy, browser will use spdy.
 // group B (npn_with_http): this means npn is enabled but spdy won't be used.
@@ skipping 1048 matching lines @@
 
   metrics->Stop();
 
   // browser_shutdown takes care of deleting browser_process, so we need to
   // release it.
   ignore_result(browser_process.release());
   browser_shutdown::Shutdown();
 
   return result_code;
 }