Warmth of a connection (cwnd) is estimated by the amount of data written to the socket.

Choosing the warmest connection would mean faster resource load times. 

idle time is the time a socket has remained idle (no http requests being served on it). 
Probability of server resetting a connection increases with idle time duration. 

Using a cost function that takes into account bytes transferred and idle time to pick best connection to schedule http requests on.

CODEREVIEW done in http://codereview.chromium.org/6990036/

Contributed by gagansingh@google.com

Review URL: http://codereview.chromium.org/7189055

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@90373 0039d316-1c4b-4281-b951-d872f2087c98

25 files changed, 353 insertions, 9 deletions

diff --git a/net/socket/client_socket_pool_base.cc b/net/socket/client_socket_pool_base.cc
index ddcbba6..d39890b 100644
--- a/net/socket/client_socket_pool_base.cc
+++ b/net/socket/client_socket_pool_base.cc
@@ -4,11 +4,14 @@
 
 #include "net/socket/client_socket_pool_base.h"
 
+#include <math.h>
 #include "base/compiler_specific.h"
 #include "base/format_macros.h"
+#include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/metrics/stats_counters.h"
 #include "base/stl_util-inl.h"
+#include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/time.h"
 #include "base/values.h"
@@ -32,10 +35,33 @@ const int kCleanupInterval = 10;  // DO NOT INCREASE THIS TIMEOUT.
 // after a certain timeout has passed without receiving an ACK.
 bool g_connect_backup_jobs_enabled = true;
 
+double g_socket_reuse_policy_penalty_exponent = -1;
+int g_socket_reuse_policy = -1;
+
 }  // namespace
 
 namespace net {
 
+int GetSocketReusePolicy() {
+  return g_socket_reuse_policy;
+}
+
+void SetSocketReusePolicy(int policy) {
+  DCHECK_GE(policy, 0);
+  DCHECK_LE(policy, 2);
+  if (policy > 2 || policy < 0) {
+    LOG(ERROR) << "Invalid socket reuse policy";
+    return;
+  }
+
+  double exponents[] = { 0, 0.25, -1 };
+  g_socket_reuse_policy_penalty_exponent = exponents[policy];
+  g_socket_reuse_policy = policy;
+
+  VLOG(1) << "Setting g_socket_reuse_policy_penalty_exponent = "
+          << g_socket_reuse_policy_penalty_exponent;
+}
+
 ConnectJob::ConnectJob(const std::string& group_name,
                        base::TimeDelta timeout_duration,
                        Delegate* delegate,
@@ -363,6 +389,7 @@ bool ClientSocketPoolBaseHelper::AssignIdleSocketToGroup(
     const Request* request, Group* group) {
   std::list<IdleSocket>* idle_sockets = group->mutable_idle_sockets();
   std::list<IdleSocket>::iterator idle_socket_it = idle_sockets->end();
+  double max_score = -1;
 
   // Iterate through the idle sockets forwards (oldest to newest)
   //   * Delete any disconnected ones.
@@ -379,7 +406,22 @@ bool ClientSocketPoolBaseHelper::AssignIdleSocketToGroup(
 
     if (it->socket->WasEverUsed()) {
       // We found one we can reuse!
-      idle_socket_it = it;
+      double score = 0;
+      int64 bytes_read = it->socket->NumBytesRead();
+      double num_kb = static_cast<double>(bytes_read) / 1024.0;
+      int idle_time_sec = (base::TimeTicks::Now() - it->start_time).InSeconds();
+      idle_time_sec = std::max(1, idle_time_sec);
+
+      if (g_socket_reuse_policy_penalty_exponent >= 0 && num_kb >= 0) {
+        score = num_kb / pow(idle_time_sec,
+                             g_socket_reuse_policy_penalty_exponent);
+      }
+
+      // Equality to prefer recently used connection.
+      if (score >= max_score) {
+        idle_socket_it = it;
+        max_score = score;
+      }
     }
 
     ++it;
diff --git a/net/socket/client_socket_pool_base.h b/net/socket/client_socket_pool_base.h
index a5defdf..2490c02 100644
--- a/net/socket/client_socket_pool_base.h
+++ b/net/socket/client_socket_pool_base.h
@@ -50,6 +50,13 @@ namespace net {
 
 class ClientSocketHandle;
 
+// Returns the client socket reuse policy.
+int GetSocketReusePolicy();
+
+// Sets the client socket reuse policy.
+// NOTE: 'policy' should be a valid ClientSocketReusePolicy enum value.
+NET_API void SetSocketReusePolicy(int policy);
+
 // ConnectJob provides an abstract interface for "connecting" a socket.
 // The connection may involve host resolution, tcp connection, ssl connection,
 // etc.
@@ -167,6 +174,17 @@ class NET_TEST ClientSocketPoolBaseHelper
     NO_IDLE_SOCKETS = 0x1,  // Do not return an idle socket. Create a new one.
   };
 
+  enum ClientSocketReusePolicy {
+    // Socket with largest amount of bytes transferred.
+    USE_WARMEST_SOCKET = 0,
+
+    // Socket which scores highest on large bytes transferred and low idle time.
+    USE_WARM_SOCKET = 1,
+
+    // Socket which was most recently used.
+    USE_LAST_ACCESSED_SOCKET = 2,
+  };
+
   class NET_TEST Request {
    public:
     Request(ClientSocketHandle* handle,
diff --git a/net/socket/client_socket_pool_base_unittest.cc b/net/socket/client_socket_pool_base_unittest.cc
index 4864001..6cdbdd3 100644
--- a/net/socket/client_socket_pool_base_unittest.cc
+++ b/net/socket/client_socket_pool_base_unittest.cc
@@ -45,12 +45,14 @@ typedef ClientSocketPoolBase<TestSocketParams> TestClientSocketPoolBase;
 
 class MockClientSocket : public StreamSocket {
  public:
-  MockClientSocket() : connected_(false), was_used_to_convey_data_(false) {}
+  MockClientSocket() : connected_(false), was_used_to_convey_data_(false),
+                       num_bytes_read_(0) {}
 
   // Socket methods:
   virtual int Read(
-      IOBuffer* /* buf */, int /* len */, CompletionCallback* /* callback */) {
-    return ERR_UNEXPECTED;
+      IOBuffer* /* buf */, int len, CompletionCallback* /* callback */) {
+    num_bytes_read_ += len;
+    return len;
   }
 
   virtual int Write(
@@ -86,13 +88,22 @@ class MockClientSocket : public StreamSocket {
 
   virtual void SetSubresourceSpeculation() {}
   virtual void SetOmniboxSpeculation() {}
-  virtual bool WasEverUsed() const { return was_used_to_convey_data_; }
+  virtual bool WasEverUsed() const {
+    return was_used_to_convey_data_ || num_bytes_read_ > 0;
+  }
   virtual bool UsingTCPFastOpen() const { return false; }
+  virtual int64 NumBytesRead() const { return num_bytes_read_; }
+  virtual base::TimeDelta GetConnectTimeMicros() const {
+    static const base::TimeDelta kDummyConnectTimeMicros =
+        base::TimeDelta::FromMicroseconds(10);
+    return kDummyConnectTimeMicros;  // Dummy value.
+  }
 
  private:
   bool connected_;
   BoundNetLog net_log_;
   bool was_used_to_convey_data_;
+  int num_bytes_read_;
 
   DISALLOW_COPY_AND_ASSIGN(MockClientSocket);
 };
@@ -604,6 +615,71 @@ class ClientSocketPoolBaseTest : public testing::Test {
   ClientSocketPoolTest test_base_;
 };
 
+TEST_F(ClientSocketPoolBaseTest, AssignIdleSocketToGroup_WarmestSocket) {
+  CreatePool(4, 4);
+  net::SetSocketReusePolicy(0);
+
+  EXPECT_EQ(OK, StartRequest("a", kDefaultPriority));
+  EXPECT_EQ(OK, StartRequest("a", kDefaultPriority));
+  EXPECT_EQ(OK, StartRequest("a", kDefaultPriority));
+  EXPECT_EQ(OK, StartRequest("a", kDefaultPriority));
+
+  std::map<int, StreamSocket*> sockets_;
+  for (size_t i = 0; i < test_base_.requests_size(); i++) {
+    TestSocketRequest* req = test_base_.request(i);
+    StreamSocket* s = req->handle()->socket();
+    MockClientSocket* sock = static_cast<MockClientSocket*>(s);
+    CHECK(sock);
+    sockets_[i] = sock;
+    sock->Read(NULL, 1024 - i, NULL);
+  }
+
+  ReleaseAllConnections(ClientSocketPoolTest::KEEP_ALIVE);
+
+  EXPECT_EQ(OK, StartRequest("a", kDefaultPriority));
+  TestSocketRequest* req = test_base_.request(test_base_.requests_size() - 1);
+
+  // First socket is warmest.
+  EXPECT_EQ(sockets_[0], req->handle()->socket());
+
+  // Test that NumBytes are as expected.
+  EXPECT_EQ(1024, sockets_[0]->NumBytesRead());
+  EXPECT_EQ(1023, sockets_[1]->NumBytesRead());
+  EXPECT_EQ(1022, sockets_[2]->NumBytesRead());
+  EXPECT_EQ(1021, sockets_[3]->NumBytesRead());
+
+  ReleaseAllConnections(ClientSocketPoolTest::NO_KEEP_ALIVE);
+}
+
+TEST_F(ClientSocketPoolBaseTest, AssignIdleSocketToGroup_LastAccessedSocket) {
+  CreatePool(4, 4);
+  net::SetSocketReusePolicy(2);
+
+  EXPECT_EQ(OK, StartRequest("a", kDefaultPriority));
+  EXPECT_EQ(OK, StartRequest("a", kDefaultPriority));
+  EXPECT_EQ(OK, StartRequest("a", kDefaultPriority));
+  EXPECT_EQ(OK, StartRequest("a", kDefaultPriority));
+
+  std::map<int, StreamSocket*> sockets_;
+  for (size_t i = 0; i < test_base_.requests_size(); i++) {
+    TestSocketRequest* req = test_base_.request(i);
+    StreamSocket* s = req->handle()->socket();
+    MockClientSocket* sock = static_cast<MockClientSocket*>(s);
+    CHECK(sock);
+    sockets_[i] = sock;
+    sock->Read(NULL, 1024 - i, NULL);
+  }
+
+  ReleaseAllConnections(ClientSocketPoolTest::KEEP_ALIVE);
+
+  EXPECT_EQ(OK, StartRequest("a", kDefaultPriority));
+  TestSocketRequest* req = test_base_.request(test_base_.requests_size() - 1);
+
+  // Last socket is most recently accessed.
+  EXPECT_EQ(sockets_[3], req->handle()->socket());
+  ReleaseAllConnections(ClientSocketPoolTest::NO_KEEP_ALIVE);
+}
+
 // Even though a timeout is specified, it doesn't time out on a synchronous
 // completion.
 TEST_F(ClientSocketPoolBaseTest, ConnectJob_NoTimeoutOnSynchronousCompletion) {
diff --git a/net/socket/socket_test_util.cc b/net/socket/socket_test_util.cc
index 4e4e8fe..0573f73 100644
--- a/net/socket/socket_test_util.cc
+++ b/net/socket/socket_test_util.cc
@@ -707,6 +707,7 @@ MockTCPClientSocket::MockTCPClientSocket(const net::AddressList& addresses,
       addresses_(addresses),
       data_(data),
       read_offset_(0),
+      num_bytes_read_(0),
       read_data_(false, net::ERR_UNEXPECTED),
       need_read_data_(true),
       peer_closed_connection_(false),
@@ -811,6 +812,17 @@ bool MockTCPClientSocket::UsingTCPFastOpen() const {
   return false;
 }
 
+int64 MockTCPClientSocket::NumBytesRead() const {
+  return num_bytes_read_;
+}
+
+base::TimeDelta MockTCPClientSocket::GetConnectTimeMicros() const {
+  // Dummy value.
+  static const base::TimeDelta kTestingConnectTimeMicros =
+      base::TimeDelta::FromMicroseconds(20);
+  return kTestingConnectTimeMicros;
+}
+
 void MockTCPClientSocket::OnReadComplete(const MockRead& data) {
   // There must be a read pending.
   DCHECK(pending_buf_);
@@ -853,6 +865,7 @@ int MockTCPClientSocket::CompleteRead() {
       result = std::min(buf_len, read_data_.data_len - read_offset_);
       memcpy(buf->data(), read_data_.data + read_offset_, result);
       read_offset_ += result;
+      num_bytes_read_ += result;
       if (read_offset_ == read_data_.data_len) {
         need_read_data_ = true;
         read_offset_ = 0;
@@ -1001,6 +1014,14 @@ bool DeterministicMockTCPClientSocket::UsingTCPFastOpen() const {
   return false;
 }
 
+int64 DeterministicMockTCPClientSocket::NumBytesRead() const {
+  return -1;
+}
+
+base::TimeDelta DeterministicMockTCPClientSocket::GetConnectTimeMicros() const {
+  return base::TimeDelta::FromMicroseconds(-1);
+}
+
 void DeterministicMockTCPClientSocket::OnReadComplete(const MockRead& data) {}
 
 class MockSSLClientSocket::ConnectCallback
@@ -1094,6 +1115,14 @@ bool MockSSLClientSocket::UsingTCPFastOpen() const {
   return transport_->socket()->UsingTCPFastOpen();
 }
 
+int64 MockSSLClientSocket::NumBytesRead() const {
+  return -1;
+}
+
+base::TimeDelta MockSSLClientSocket::GetConnectTimeMicros() const {
+  return base::TimeDelta::FromMicroseconds(-1);
+}
+
 void MockSSLClientSocket::GetSSLInfo(net::SSLInfo* ssl_info) {
   ssl_info->Reset();
   ssl_info->cert = data_->cert_;
diff --git a/net/socket/socket_test_util.h b/net/socket/socket_test_util.h
index 9a31288..d1f4816 100644
--- a/net/socket/socket_test_util.h
+++ b/net/socket/socket_test_util.h
@@ -631,6 +631,8 @@ class MockTCPClientSocket : public MockClientSocket {
   virtual int GetPeerAddress(AddressList* address) const;
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
   // MockClientSocket:
   virtual void OnReadComplete(const MockRead& data);
@@ -642,6 +644,7 @@ class MockTCPClientSocket : public MockClientSocket {
 
   net::SocketDataProvider* data_;
   int read_offset_;
+  int num_bytes_read_;
   net::MockRead read_data_;
   bool need_read_data_;
 
@@ -683,6 +686,8 @@ class DeterministicMockTCPClientSocket : public MockClientSocket,
   virtual bool IsConnectedAndIdle() const;
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
   // MockClientSocket:
   virtual void OnReadComplete(const MockRead& data);
@@ -724,6 +729,8 @@ class MockSSLClientSocket : public MockClientSocket {
   virtual bool IsConnected() const;
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
   // SSLClientSocket methods:
   virtual void GetSSLInfo(net::SSLInfo* ssl_info);
diff --git a/net/socket/socks5_client_socket.cc b/net/socket/socks5_client_socket.cc
index 7a1c10d..2f5cee4 100644
--- a/net/socket/socks5_client_socket.cc
+++ b/net/socket/socks5_client_socket.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -142,6 +142,22 @@ bool SOCKS5ClientSocket::UsingTCPFastOpen() const {
   return false;
 }
 
+int64 SOCKS5ClientSocket::NumBytesRead() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->NumBytesRead();
+  }
+  NOTREACHED();
+  return -1;
+}
+
+base::TimeDelta SOCKS5ClientSocket::GetConnectTimeMicros() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->GetConnectTimeMicros();
+  }
+  NOTREACHED();
+  return base::TimeDelta::FromMicroseconds(-1);
+}
+
 // Read is called by the transport layer above to read. This can only be done
 // if the SOCKS handshake is complete.
 int SOCKS5ClientSocket::Read(IOBuffer* buf, int buf_len,
diff --git a/net/socket/socks5_client_socket.h b/net/socket/socks5_client_socket.h
index 955ad90..a9d30df 100644
--- a/net/socket/socks5_client_socket.h
+++ b/net/socket/socks5_client_socket.h
@@ -60,6 +60,8 @@ class NET_TEST SOCKS5ClientSocket : public StreamSocket {
   virtual void SetOmniboxSpeculation();
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
   // Socket methods:
   virtual int Read(IOBuffer* buf, int buf_len, CompletionCallback* callback);
diff --git a/net/socket/socks_client_socket.cc b/net/socket/socks_client_socket.cc
index d885f15..4a45b01 100644
--- a/net/socket/socks_client_socket.cc
+++ b/net/socket/socks_client_socket.cc
@@ -169,6 +169,22 @@ bool SOCKSClientSocket::UsingTCPFastOpen() const {
   return false;
 }
 
+int64 SOCKSClientSocket::NumBytesRead() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->NumBytesRead();
+  }
+  NOTREACHED();
+  return -1;
+}
+
+base::TimeDelta SOCKSClientSocket::GetConnectTimeMicros() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->GetConnectTimeMicros();
+  }
+  NOTREACHED();
+  return base::TimeDelta::FromMicroseconds(-1);
+}
+
 
 // Read is called by the transport layer above to read. This can only be done
 // if the SOCKS handshake is complete.
diff --git a/net/socket/socks_client_socket.h b/net/socket/socks_client_socket.h
index 7c4ba35..286538f 100644
--- a/net/socket/socks_client_socket.h
+++ b/net/socket/socks_client_socket.h
@@ -58,6 +58,8 @@ class NET_TEST SOCKSClientSocket : public StreamSocket {
   virtual void SetOmniboxSpeculation();
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
   // Socket methods:
   virtual int Read(IOBuffer* buf, int buf_len, CompletionCallback* callback);
diff --git a/net/socket/ssl_client_socket_mac.cc b/net/socket/ssl_client_socket_mac.cc
index 2fc11ec..c38b78a 100644
--- a/net/socket/ssl_client_socket_mac.cc
+++ b/net/socket/ssl_client_socket_mac.cc
@@ -658,6 +658,22 @@ bool SSLClientSocketMac::UsingTCPFastOpen() const {
   return false;
 }
 
+int64 SSLClientSocketMac::NumBytesRead() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->NumBytesRead();
+  }
+  NOTREACHED();
+  return -1;
+}
+
+base::TimeDelta SSLClientSocketMac::GetConnectTimeMicros() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->GetConnectTimeMicros();
+  }
+  NOTREACHED();
+  return base::TimeDelta::FromMicroseconds(-1);
+}
+
 int SSLClientSocketMac::Read(IOBuffer* buf, int buf_len,
                              CompletionCallback* callback) {
   DCHECK(completed_handshake());
diff --git a/net/socket/ssl_client_socket_mac.h b/net/socket/ssl_client_socket_mac.h
index 4dbffe6..8ef33e9 100644
--- a/net/socket/ssl_client_socket_mac.h
+++ b/net/socket/ssl_client_socket_mac.h
@@ -57,6 +57,8 @@ class SSLClientSocketMac : public SSLClientSocket {
   virtual void SetOmniboxSpeculation();
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
   // Socket methods:
   virtual int Read(IOBuffer* buf, int buf_len, CompletionCallback* callback);
diff --git a/net/socket/ssl_client_socket_nss.cc b/net/socket/ssl_client_socket_nss.cc
index 18b4e58..9657026 100644
--- a/net/socket/ssl_client_socket_nss.cc
+++ b/net/socket/ssl_client_socket_nss.cc
@@ -714,6 +714,22 @@ bool SSLClientSocketNSS::UsingTCPFastOpen() const {
   return false;
 }
 
+int64 SSLClientSocketNSS::NumBytesRead() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->NumBytesRead();
+  }
+  NOTREACHED();
+  return -1;
+}
+
+base::TimeDelta SSLClientSocketNSS::GetConnectTimeMicros() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->GetConnectTimeMicros();
+  }
+  NOTREACHED();
+  return base::TimeDelta::FromMicroseconds(-1);
+}
+
 int SSLClientSocketNSS::Read(IOBuffer* buf, int buf_len,
                              CompletionCallback* callback) {
   EnterFunction(buf_len);
diff --git a/net/socket/ssl_client_socket_nss.h b/net/socket/ssl_client_socket_nss.h
index 1c5d80e..7d2f7cf 100644
--- a/net/socket/ssl_client_socket_nss.h
+++ b/net/socket/ssl_client_socket_nss.h
@@ -75,6 +75,8 @@ class SSLClientSocketNSS : public SSLClientSocket {
   virtual void SetOmniboxSpeculation();
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
   // Socket methods:
   virtual int Read(IOBuffer* buf, int buf_len, CompletionCallback* callback);
diff --git a/net/socket/ssl_client_socket_win.cc b/net/socket/ssl_client_socket_win.cc
index 1392e1d..4cc3103 100644
--- a/net/socket/ssl_client_socket_win.cc
+++ b/net/socket/ssl_client_socket_win.cc
@@ -731,6 +731,22 @@ bool SSLClientSocketWin::UsingTCPFastOpen() const {
   return false;
 }
 
+int64 SSLClientSocketWin::NumBytesRead() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->NumBytesRead();
+  }
+  NOTREACHED();
+  return -1;
+}
+
+base::TimeDelta SSLClientSocketWin::GetConnectTimeMicros() const {
+  if (transport_.get() && transport_->socket()) {
+    return transport_->socket()->GetConnectTimeMicros();
+  }
+  NOTREACHED();
+  return base::TimeDelta::FromMicroseconds(-1);
+}
+
 int SSLClientSocketWin::Read(IOBuffer* buf, int buf_len,
                              CompletionCallback* callback) {
   DCHECK(completed_handshake());
diff --git a/net/socket/ssl_client_socket_win.h b/net/socket/ssl_client_socket_win.h
index fb54c43..59f403a 100644
--- a/net/socket/ssl_client_socket_win.h
+++ b/net/socket/ssl_client_socket_win.h
@@ -62,6 +62,8 @@ class SSLClientSocketWin : public SSLClientSocket {
   virtual void SetOmniboxSpeculation();
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
   // Socket methods:
   virtual int Read(IOBuffer* buf, int buf_len, CompletionCallback* callback);
diff --git a/net/socket/ssl_server_socket_nss.cc b/net/socket/ssl_server_socket_nss.cc
index 0f35ce9c..b272f8e 100644
--- a/net/socket/ssl_server_socket_nss.cc
+++ b/net/socket/ssl_server_socket_nss.cc
@@ -226,6 +226,14 @@ bool SSLServerSocketNSS::UsingTCPFastOpen() const {
   return transport_socket_->UsingTCPFastOpen();
 }
 
+int64 SSLServerSocketNSS::NumBytesRead() const {
+  return transport_socket_->NumBytesRead();
+}
+
+base::TimeDelta SSLServerSocketNSS::GetConnectTimeMicros() const {
+  return transport_socket_->GetConnectTimeMicros();
+}
+
 int SSLServerSocketNSS::InitializeSSLOptions() {
   // Transport connected, now hook it up to nss
   // TODO(port): specify rx and tx buffer sizes separately
diff --git a/net/socket/ssl_server_socket_nss.h b/net/socket/ssl_server_socket_nss.h
index 366a915..5903c17 100644
--- a/net/socket/ssl_server_socket_nss.h
+++ b/net/socket/ssl_server_socket_nss.h
@@ -54,6 +54,8 @@ class SSLServerSocketNSS : public SSLServerSocket {
   virtual void SetOmniboxSpeculation();
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
  private:
   enum State {
diff --git a/net/socket/ssl_server_socket_unittest.cc b/net/socket/ssl_server_socket_unittest.cc
index 02f333b..de89c20 100644
--- a/net/socket/ssl_server_socket_unittest.cc
+++ b/net/socket/ssl_server_socket_unittest.cc
@@ -171,6 +171,14 @@ class FakeSocket : public StreamSocket {
     return false;
   }
 
+  virtual int64 NumBytesRead() const {
+    return -1;
+  }
+
+  virtual base::TimeDelta GetConnectTimeMicros() const {
+    return base::TimeDelta::FromMicroseconds(-1);
+  }
+
  private:
   net::BoundNetLog net_log_;
   FakeDataChannel* incoming_;
diff --git a/net/socket/stream_socket.h b/net/socket/stream_socket.h
index 544fbcd..ef2f698 100644
--- a/net/socket/stream_socket.h
+++ b/net/socket/stream_socket.h
@@ -6,6 +6,7 @@
 #define NET_SOCKET_STREAM_SOCKET_H_
 #pragma once
 
+#include "base/time.h"
 #include "net/base/net_log.h"
 #include "net/socket/socket.h"
 
@@ -79,6 +80,12 @@ class NET_TEST StreamSocket : public Socket {
   // TCP FastOpen is an experiment with sending data in the TCP SYN packet.
   virtual bool UsingTCPFastOpen() const = 0;
 
+  // Returns the number of bytes successfully read from this socket.
+  virtual int64 NumBytesRead() const = 0;
+
+  // Returns the connection setup time of this socket.
+  virtual base::TimeDelta GetConnectTimeMicros() const = 0;
+
  protected:
   // The following class is only used to gather statistics about the history of
   // a socket.  It is only instantiated and used in basic sockets, such as
diff --git a/net/socket/tcp_client_socket_libevent.cc b/net/socket/tcp_client_socket_libevent.cc
index 38c3446..27c106c 100644
--- a/net/socket/tcp_client_socket_libevent.cc
+++ b/net/socket/tcp_client_socket_libevent.cc
@@ -137,7 +137,8 @@ TCPClientSocketLibevent::TCPClientSocketLibevent(
       net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_SOCKET)),
       previously_disconnected_(false),
       use_tcp_fastopen_(false),
-      tcp_fastopen_connected_(false) {
+      tcp_fastopen_connected_(false),
+      num_bytes_read_(0) {
   scoped_refptr<NetLog::EventParameters> params;
   if (source.is_valid())
     params = new NetLogSourceParameter("source_dependency", source);
@@ -298,6 +299,7 @@ int TCPClientSocketLibevent::DoConnect() {
 
   // Connect the socket.
   if (!use_tcp_fastopen_) {
+    connect_start_time_ = base::TimeTicks::Now();
     if (!HANDLE_EINTR(connect(socket_, current_ai_->ai_addr,
                               static_cast<int>(current_ai_->ai_addrlen)))) {
       // Connected without waiting!
@@ -339,6 +341,7 @@ int TCPClientSocketLibevent::DoConnectComplete(int result) {
   write_socket_watcher_.StopWatchingFileDescriptor();
 
   if (result == OK) {
+    connect_time_micros_ = base::TimeTicks::Now() - connect_start_time_;
     use_history_.set_was_ever_connected();
     return OK;  // Done!
   }
@@ -440,6 +443,7 @@ int TCPClientSocketLibevent::Read(IOBuffer* buf,
   if (nread >= 0) {
     base::StatsCounter read_bytes("tcp.read_bytes");
     read_bytes.Add(nread);
+    num_bytes_read_ += static_cast<int64>(nread);
     if (nread > 0)
       use_history_.set_was_used_to_convey_data();
     net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_RECEIVED, nread,
@@ -634,6 +638,7 @@ void TCPClientSocketLibevent::DidCompleteRead() {
     result = bytes_transferred;
     base::StatsCounter read_bytes("tcp.read_bytes");
     read_bytes.Add(bytes_transferred);
+    num_bytes_read_ += static_cast<int64>(bytes_transferred);
     if (bytes_transferred > 0)
       use_history_.set_was_used_to_convey_data();
     net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_RECEIVED, result,
@@ -723,4 +728,12 @@ bool TCPClientSocketLibevent::UsingTCPFastOpen() const {
   return use_tcp_fastopen_;
 }
 
+int64 TCPClientSocketLibevent::NumBytesRead() const {
+  return num_bytes_read_;
+}
+
+base::TimeDelta TCPClientSocketLibevent::GetConnectTimeMicros() const {
+  return connect_time_micros_;
+}
+
 }  // namespace net
diff --git a/net/socket/tcp_client_socket_libevent.h b/net/socket/tcp_client_socket_libevent.h
index 607b9ee..f5e4a28 100644
--- a/net/socket/tcp_client_socket_libevent.h
+++ b/net/socket/tcp_client_socket_libevent.h
@@ -53,6 +53,8 @@ class TCPClientSocketLibevent : public StreamSocket, base::NonThreadSafe {
   virtual void SetOmniboxSpeculation();
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
   // Socket methods:
   // Multiple outstanding requests are not supported.
@@ -195,6 +197,10 @@ class TCPClientSocketLibevent : public StreamSocket, base::NonThreadSafe {
   // True when TCP FastOpen is in use and we have done the connect.
   bool tcp_fastopen_connected_;
 
+  base::TimeTicks connect_start_time_;
+  base::TimeDelta connect_time_micros_;
+  int64 num_bytes_read_;
+
   DISALLOW_COPY_AND_ASSIGN(TCPClientSocketLibevent);
 };
 
diff --git a/net/socket/tcp_client_socket_win.cc b/net/socket/tcp_client_socket_win.cc
index 71187a1..f4026b7 100644
--- a/net/socket/tcp_client_socket_win.cc
+++ b/net/socket/tcp_client_socket_win.cc
@@ -323,7 +323,8 @@ TCPClientSocketWin::TCPClientSocketWin(const AddressList& addresses,
       next_connect_state_(CONNECT_STATE_NONE),
       connect_os_error_(0),
       net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_SOCKET)),
-      previously_disconnected_(false) {
+      previously_disconnected_(false),
+      num_bytes_read_(0) {
   scoped_refptr<NetLog::EventParameters> params;
   if (source.is_valid())
     params = new NetLogSourceParameter("source_dependency", source);
@@ -484,6 +485,7 @@ int TCPClientSocketWin::DoConnect() {
 
   core_->write_overlapped_.hEvent = WSACreateEvent();
 
+  connect_start_time_ = base::TimeTicks::Now();
   if (!connect(socket_, ai->ai_addr, static_cast<int>(ai->ai_addrlen))) {
     // Connected without waiting!
     //
@@ -522,6 +524,7 @@ int TCPClientSocketWin::DoConnectComplete(int result) {
   net_log_.EndEvent(NetLog::TYPE_TCP_CONNECT_ATTEMPT, params);
 
   if (result == OK) {
+    connect_time_micros_ = base::TimeTicks::Now() - connect_start_time_;
     use_history_.set_was_ever_connected();
     return OK;  // Done!
   }
@@ -658,6 +661,14 @@ bool TCPClientSocketWin::UsingTCPFastOpen() const {
   return false;
 }
 
+int64 TCPClientSocketWin::NumBytesRead() const {
+  return num_bytes_read_;
+}
+
+base::TimeDelta TCPClientSocketWin::GetConnectTimeMicros() const {
+  return connect_time_micros_;
+}
+
 int TCPClientSocketWin::Read(IOBuffer* buf,
                              int buf_len,
                              CompletionCallback* callback) {
@@ -688,6 +699,7 @@ int TCPClientSocketWin::Read(IOBuffer* buf,
       base::MemoryDebug::MarkAsInitialized(core_->read_buffer_.buf, num);
       base::StatsCounter read_bytes("tcp.read_bytes");
       read_bytes.Add(num);
+      num_bytes_read_ += num;
       if (num > 0)
         use_history_.set_was_used_to_convey_data();
       net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_RECEIVED, num,
@@ -858,6 +870,7 @@ void TCPClientSocketWin::DidCompleteRead() {
   if (ok) {
     base::StatsCounter read_bytes("tcp.read_bytes");
     read_bytes.Add(num_bytes);
+    num_bytes_read_ += num_bytes;
     if (num_bytes > 0)
       use_history_.set_was_used_to_convey_data();
     net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_RECEIVED,
diff --git a/net/socket/tcp_client_socket_win.h b/net/socket/tcp_client_socket_win.h
index 3282772..b1f9f3b 100644
--- a/net/socket/tcp_client_socket_win.h
+++ b/net/socket/tcp_client_socket_win.h
@@ -53,6 +53,8 @@ class NET_API TCPClientSocketWin : public StreamSocket,
   virtual void SetOmniboxSpeculation();
   virtual bool WasEverUsed() const;
   virtual bool UsingTCPFastOpen() const;
+  virtual int64 NumBytesRead() const;
+  virtual base::TimeDelta GetConnectTimeMicros() const;
 
   // Socket methods:
   // Multiple outstanding requests are not supported.
@@ -141,6 +143,10 @@ class NET_API TCPClientSocketWin : public StreamSocket,
   // histograms.
   UseHistory use_history_;
 
+  base::TimeTicks connect_start_time_;
+  base::TimeDelta connect_time_micros_;
+  int64 num_bytes_read_;
+
   DISALLOW_COPY_AND_ASSIGN(TCPClientSocketWin);
 };
 
diff --git a/net/socket/transport_client_socket_pool_unittest.cc b/net/socket/transport_client_socket_pool_unittest.cc
index 5716a4d..d12cd9d 100644
--- a/net/socket/transport_client_socket_pool_unittest.cc
+++ b/net/socket/transport_client_socket_pool_unittest.cc
@@ -85,6 +85,10 @@ class MockClientSocket : public StreamSocket {
   virtual void SetOmniboxSpeculation() {}
   virtual bool WasEverUsed() const { return false; }
   virtual bool UsingTCPFastOpen() const { return false; }
+  virtual int64 NumBytesRead() const { return -1; }
+  virtual base::TimeDelta GetConnectTimeMicros() const {
+    return base::TimeDelta::FromMicroseconds(-1);
+  }
 
   // Socket methods:
   virtual int Read(IOBuffer* buf, int buf_len,
@@ -135,6 +139,10 @@ class MockFailingClientSocket : public StreamSocket {
   virtual void SetOmniboxSpeculation() {}
   virtual bool WasEverUsed() const { return false; }
   virtual bool UsingTCPFastOpen() const { return false; }
+  virtual int64 NumBytesRead() const { return -1; }
+  virtual base::TimeDelta GetConnectTimeMicros() const {
+    return base::TimeDelta::FromMicroseconds(-1);
+  }
 
   // Socket methods:
   virtual int Read(IOBuffer* buf, int buf_len,
@@ -209,6 +217,10 @@ class MockPendingClientSocket : public StreamSocket {
   virtual void SetOmniboxSpeculation() {}
   virtual bool WasEverUsed() const { return false; }
   virtual bool UsingTCPFastOpen() const { return false; }
+  virtual int64 NumBytesRead() const { return -1; }
+  virtual base::TimeDelta GetConnectTimeMicros() const {
+    return base::TimeDelta::FromMicroseconds(-1);
+  }
 
   // Socket methods:
   virtual int Read(IOBuffer* buf, int buf_len,
diff --git a/net/socket/transport_client_socket_unittest.cc b/net/socket/transport_client_socket_unittest.cc
index bb0be35..8f377e5 100644
--- a/net/socket/transport_client_socket_unittest.cc
+++ b/net/socket/transport_client_socket_unittest.cc
@@ -277,6 +277,8 @@ TEST_P(TransportClientSocketTest, Read) {
 
   rv = sock_->Read(buf, 4096, &callback);
   ASSERT_EQ(ERR_IO_PENDING, rv);
+  EXPECT_EQ(static_cast<int64>(std::string(kServerReply).size()),
+            sock_->NumBytesRead());
   CloseServerSocket();
   EXPECT_EQ(0, callback.WaitForResult());
 }
@@ -309,6 +311,8 @@ TEST_P(TransportClientSocketTest, Read_SmallChunks) {
   // then close the server socket, and note the close.
 
   rv = sock_->Read(buf, 1, &callback);
+  EXPECT_EQ(static_cast<int64>(std::string(kServerReply).size()),
+            sock_->NumBytesRead());
   ASSERT_EQ(ERR_IO_PENDING, rv);
   CloseServerSocket();
   EXPECT_EQ(0, callback.WaitForResult());
@@ -329,9 +333,12 @@ TEST_P(TransportClientSocketTest, Read_Interrupted) {
   scoped_refptr<IOBuffer> buf(new IOBuffer(16));
   rv = sock_->Read(buf, 16, &callback);
   EXPECT_TRUE(rv >= 0 || rv == ERR_IO_PENDING);
+  EXPECT_EQ(0, sock_->NumBytesRead());
 
-  if (rv == ERR_IO_PENDING)
+  if (rv == ERR_IO_PENDING) {
     rv = callback.WaitForResult();
+    EXPECT_EQ(16, sock_->NumBytesRead());
+  }
 
   EXPECT_NE(0, rv);
 }