| // 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. |
| |
| #include "net/socket/stream_socket.h" |
| |
| #include "base/metrics/field_trial.h" |
| #include "base/metrics/histogram_macros.h" |
| #include "base/strings/string_number_conversions.h" |
| #include "base/values.h" |
| |
| namespace net { |
| |
| StreamSocket::UseHistory::UseHistory() |
| : was_ever_connected_(false), |
| was_used_to_convey_data_(false), |
| omnibox_speculation_(false), |
| subresource_speculation_(false) { |
| } |
| |
| StreamSocket::UseHistory::~UseHistory() { |
| EmitPreconnectionHistograms(); |
| } |
| |
| void StreamSocket::UseHistory::Reset() { |
| EmitPreconnectionHistograms(); |
| was_ever_connected_ = false; |
| was_used_to_convey_data_ = false; |
| // omnibox_speculation_ and subresource_speculation_ values |
| // are intentionally preserved. |
| } |
| |
| void StreamSocket::UseHistory::set_was_ever_connected() { |
| DCHECK(!was_used_to_convey_data_); |
| was_ever_connected_ = true; |
| } |
| |
| void StreamSocket::UseHistory::set_was_used_to_convey_data() { |
| DCHECK(was_ever_connected_); |
| was_used_to_convey_data_ = true; |
| } |
| |
| |
| void StreamSocket::UseHistory::set_subresource_speculation() { |
| DCHECK(was_ever_connected_); |
| // TODO(jar): We should transition to marking a socket (or stream) at |
| // construction time as being created for speculative reasons. This current |
| // approach of trying to track use of a socket to convey data can make |
| // mistakes when other sockets (such as ones sitting in the pool for a long |
| // time) are issued. Unused sockets can be left over when a when a set of |
| // connections to a host are made, and one is "unlucky" and takes so long to |
| // complete a connection, that another socket is used, and recycled before a |
| // second connection comes available. Similarly, re-try connections can leave |
| // an original (slow to connect socket) in the pool, and that can be issued |
| // to a speculative requester. In any cases such old sockets will fail when an |
| // attempt is made to used them!... and then it will look like a speculative |
| // socket was discarded without any user!?!?! |
| if (was_used_to_convey_data_) |
| return; |
| subresource_speculation_ = true; |
| } |
| |
| void StreamSocket::UseHistory::set_omnibox_speculation() { |
| DCHECK(was_ever_connected_); |
| if (was_used_to_convey_data_) |
| return; |
| omnibox_speculation_ = true; |
| } |
| |
| bool StreamSocket::UseHistory::was_used_to_convey_data() const { |
| DCHECK(!was_used_to_convey_data_ || was_ever_connected_); |
| return was_used_to_convey_data_; |
| } |
| |
| void StreamSocket::UseHistory::EmitPreconnectionHistograms() const { |
| DCHECK(!subresource_speculation_ || !omnibox_speculation_); |
| // 0 ==> non-speculative, never connected. |
| // 1 ==> non-speculative never used (but connected). |
| // 2 ==> non-speculative and used. |
| // 3 ==> omnibox_speculative never connected. |
| // 4 ==> omnibox_speculative never used (but connected). |
| // 5 ==> omnibox_speculative and used. |
| // 6 ==> subresource_speculative never connected. |
| // 7 ==> subresource_speculative never used (but connected). |
| // 8 ==> subresource_speculative and used. |
| int result; |
| if (was_used_to_convey_data_) |
| result = 2; |
| else if (was_ever_connected_) |
| result = 1; |
| else |
| result = 0; // Never used, and not really connected. |
| |
| if (omnibox_speculation_) |
| result += 3; |
| else if (subresource_speculation_) |
| result += 6; |
| UMA_HISTOGRAM_ENUMERATION("Net.PreconnectUtilization2", result, 9); |
| } |
| |
| } // namespace net |