Collect stats to investigate the viability of UDP

chrome/browser/net/network_stats.cc

+// 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 "chrome/browser/net/network_stats.h"
+
+#include "base/callback_old.h"
+#include "base/logging.h"
+#include "base/message_loop.h"
+#include "base/metrics/field_trial.h"
+#include "base/metrics/histogram.h"
+#include "base/task.h"
+#include "base/threading/platform_thread.h"
+#include "base/time.h"
+#include "base/tuple.h"
+#include "content/browser/browser_thread.h"
+#include "net/base/address_list.h"
+#include "net/base/host_resolver.h"
+#include "net/base/net_errors.h"
+#include "net/base/net_util.h"
+#include "net/base/network_change_notifier.h"
+#include "net/base/sys_addrinfo.h"
+#include "net/base/test_completion_callback.h"
+#include "net/socket/tcp_client_socket.h"
+#include "net/udp/udp_client_socket.h"
+#include "net/udp/udp_server_socket.h"
+
+namespace chrome_browser_net {
+
+// This specifies the number of bytes to be sent to the TCP/UDP servers as part
+// of small packet size test.
+static const int kSmallTestBytesToSend = 100;
+
+// This specifies the number of bytes to be sent to the TCP/UDP servers as part
+// of large packet size test.
+static const int kLargeTestBytesToSend = 1200;
+
+// NetworkStats methods and members.
+NetworkStats::NetworkStats()
+    : bytes_to_read_(0),
+      bytes_to_send_(0),
+      ALLOW_THIS_IN_INITIALIZER_LIST(
+          read_callback_(this, &NetworkStats::OnReadComplete)),
+      ALLOW_THIS_IN_INITIALIZER_LIST(
+          write_callback_(this, &NetworkStats::OnWriteComplete)),
+      finished_callback_(NULL),
+      start_time_(base::TimeTicks::Now()) {
+}
+
+NetworkStats::~NetworkStats() {
+  socket_.reset();
+  read_buffer_ = NULL;
+}
+
+void NetworkStats::Initialize(int bytes_to_send,
+                              net::CompletionCallback* finished_callback) {
+  DCHECK(bytes_to_send);   // We should have data to send.
+
+  load_size_ = bytes_to_send;
+  bytes_to_send_ = bytes_to_send;
+  bytes_to_read_ = bytes_to_send;
+  finished_callback_ = finished_callback;
+}
+
+void NetworkStats::set_socket(net::Socket* socket) {
+  DCHECK(socket);
+  DCHECK(!socket_.get());
+  socket_.reset(socket);
+}
+
+bool NetworkStats::ConnectComplete(int result) {
+  if (result < 0) {
+    Finish(CONNECT_FAILED, result);
+    return false;
+  }
+
+  DCHECK(bytes_to_send_);   // We should have data to send.
+
+  start_time_ = base::TimeTicks::Now();
+
+  int rv = SendData();
+  if (rv < 0) {
+    if (rv != net::ERR_IO_PENDING) {
+      Finish(WRITE_FAILED, rv);
+      return false;
+    }
+  }
+
+  stream_.Reset();
+  ReadData();
+
+  return true;
+}
+
+void NetworkStats::DoFinishCallback(int result) {
+  if (finished_callback_ != NULL) {
+    net::CompletionCallback* callback = finished_callback_;
+    finished_callback_ = NULL;
+    callback->Run(result);
+  }
+}
+
+bool NetworkStats::ReadComplete(int result) {
+  DCHECK(socket_.get());
+  if (result < 0) {
+    Finish(READ_FAILED, result);
+    return true;
+  }
+
+  if (!stream_.VerifyBytes(read_buffer_->data(), result)) {
+    Finish(READ_VERIFY_FAILED, net::ERR_INVALID_RESPONSE);
+    return true;
+  }
+
+  read_buffer_ = NULL;
+  bytes_to_read_ -= result;
+
+  // No more data to read.
+  if (!bytes_to_read_) {
+    Finish(SUCCESS, net::OK);
+    return true;
+  }
+  ReadData();
+  return false;
+}
+
+void NetworkStats::OnReadComplete(int result) {
+  ReadComplete(result);
+}
+
+void NetworkStats::OnWriteComplete(int result) {
+  DCHECK(socket_.get());
+  if (result < 0) {
+    Finish(WRITE_FAILED, result);
+    return;
+  }
+
+  write_buffer_->DidConsume(result);
+  bytes_to_send_ -= result;
+  if (!write_buffer_->BytesRemaining())
+      write_buffer_ = NULL;
+
+  if (bytes_to_send_) {
+    int rv = SendData();
+    if (rv < 0) {
+      if (rv != net::ERR_IO_PENDING) {
+        Finish(WRITE_FAILED, rv);
+        return;
+      }
+    }
+  }
+}
+
+void NetworkStats::ReadData() {
+  DCHECK(!read_buffer_.get());
+  // We release the read_buffer_ in the destructor if there is an error.
+  read_buffer_ = new net::IOBuffer(kMaxMessage);
+
+  int rv;
+  do {
+    DCHECK(socket_.get());
+    rv = socket_->Read(read_buffer_, kMaxMessage, &read_callback_);
+    if (rv == net::ERR_IO_PENDING)
+      return;
+    if (ReadComplete(rv))  // Complete the read manually.
+      return;
+  } while (rv > 0);
+}
+
+int NetworkStats::SendData() {
+  DCHECK(bytes_to_send_);   // We should have data to send.
+  do {
+    if (!write_buffer_.get()) {
+      scoped_refptr<net::IOBuffer> buffer(new net::IOBuffer(bytes_to_send_));
+      stream_.GetBytes(buffer->data(), bytes_to_send_);
+      write_buffer_ = new net::DrainableIOBuffer(buffer, bytes_to_send_);
+    }
+
+    DCHECK(socket_.get());
+    int rv = socket_->Write(write_buffer_,
+                            write_buffer_->BytesRemaining(),
+                            &write_callback_);
+    if (rv < 0)
+      return rv;
+    write_buffer_->DidConsume(rv);
+    bytes_to_send_ -= rv;
+    if (!write_buffer_->BytesRemaining())
+      write_buffer_ = NULL;
+  } while (bytes_to_send_);
+  return net::OK;
+}
+
+// UDPStatsClient methods and members.
+UDPStatsClient::UDPStatsClient()
+    : NetworkStats() {
+}
+
+UDPStatsClient::~UDPStatsClient() {
+}
+
+bool UDPStatsClient::Start(const std::string& ip_str,
+                           int port,
+                           int bytes_to_send,
+                           net::CompletionCallback* finished_callback) {
+  DCHECK(port);
+  DCHECK(bytes_to_send);   // We should have data to send.
+
+  AddRef();  // Released on Finish().
+
+  Initialize(bytes_to_send, finished_callback);
+
+  net::IPAddressNumber ip_number;
+  if (!net::ParseIPLiteralToNumber(ip_str, &ip_number)) {
+    Finish(IP_STRING_PARSE_FAILED, net::ERR_INVALID_ARGUMENT);
+    return false;
+  }
+  net::IPEndPoint server_address = net::IPEndPoint(ip_number, port);
+
+  net::UDPClientSocket* udp_socket =
+     new net::UDPClientSocket(NULL, net::NetLog::Source());
+  DCHECK(udp_socket);
+  set_socket(udp_socket);
+
+  int rv = udp_socket->Connect(server_address);
+  return ConnectComplete(rv);
+}
+
+void UDPStatsClient::Finish(Status status, int result) {
+  base::TimeDelta duration = base::TimeTicks::Now() - start_time();
+  if (load_size() == kSmallTestBytesToSend) {
+    if (result == net::OK)
+      UMA_HISTOGRAM_TIMES("NetConnectivity.UDP.Success.100B.RTT", duration);
+    else
+      UMA_HISTOGRAM_TIMES("NetConnectivity.UDP.Fail.100B.RTT", duration);
+
+    UMA_HISTOGRAM_ENUMERATION(
+        "NetConnectivity.UDP.Status.100B", status, STATUS_MAX);
+  } else {
+    if (result == net::OK)
+      UMA_HISTOGRAM_TIMES("NetConnectivity.UDP.Success.1K.RTT", duration);
+    else
+      UMA_HISTOGRAM_TIMES("NetConnectivity.UDP.Fail.1K.RTT", duration);
+
+    UMA_HISTOGRAM_ENUMERATION(
+        "NetConnectivity.UDP.Status.1K", status, STATUS_MAX);
+  }
+
+  DoFinishCallback(result);
+
+  // Close the socket so that there are no more IO operations.
+  net::UDPClientSocket* udp_socket =
+      static_cast<net::UDPClientSocket*>(socket().get());
+  if (udp_socket)
+    udp_socket->Close();
+
+  // We may be holding the last reference. Do not access |this| after Release().
+  Release();  // Acquired on Start().
+}
+
+// TCPStatsClient methods and members.
+TCPStatsClient::TCPStatsClient()
+  : NetworkStats(),
+    ALLOW_THIS_IN_INITIALIZER_LIST(
+        connect_callback_(this, &TCPStatsClient::OnConnectComplete)) {
+}
+
+TCPStatsClient::~TCPStatsClient() {
+}
+
+bool TCPStatsClient::Start(const net::HostPortPair& server_host_port_pair,
+                           int bytes_to_send,
+                           net::CompletionCallback* finished_callback) {
+  DCHECK(bytes_to_send);   // We should have data to send.
+
+  AddRef();  // Released on Finish().
+
+  Initialize(bytes_to_send, finished_callback);
+
+  scoped_ptr<net::HostResolver> system_host_resolver(
+      net::CreateSystemHostResolver(net::HostResolver::kDefaultParallelism,
+                                    net::HostResolver::kDefaultRetryAttempts,
+                                    NULL));
+  net::SingleRequestHostResolver host_resolver(system_host_resolver.get());
+  net::HostResolver::RequestInfo request(server_host_port_pair);
+  net::AddressList addresses;
+  int rv = host_resolver.Resolve(request, &addresses, NULL, net::BoundNetLog());

[willchan no longer on Chromium, 2011/06/06 09:25:49]

Wait, is this a synchronous HostResolver call? I don't see a callback. This will
block the IO thread, right? And why aren't we using the HostResolverImpl in the
IOThread? We do our prioritization and scheduling of requests by using the same
HostResolver instance for everything, so creating your own here bypasses those
restrictions.

[ramant (doing other things), 2011/06/07 20:54:00]

Many many thanks for pointing this out. Added the callback and used the host
resolver from io_thread.

Done.

+  if (rv != net::OK) {
+    Finish(RESOLVE_FAILED, rv);
+    return false;
+  }
+
+  net::TCPClientSocket* tcp_socket =
+      new net::TCPClientSocket(addresses, NULL, net::NetLog::Source());
+  DCHECK(tcp_socket);
+  set_socket(tcp_socket);
+
+  rv = tcp_socket->Connect(&connect_callback_);
+  if (rv == net::ERR_IO_PENDING)
+    return true;
+
+  return ConnectComplete(rv);
+}
+
+void TCPStatsClient::OnConnectComplete(int result) {
+  ConnectComplete(result);
+}
+
+void TCPStatsClient::Finish(Status status, int result) {
+  base::TimeDelta duration = base::TimeTicks::Now() - start_time();
+  if (load_size() == kSmallTestBytesToSend) {
+    if (result == net::OK)
+      UMA_HISTOGRAM_TIMES("NetConnectivity.TCP.Success.100B.RTT", duration);
+    else
+      UMA_HISTOGRAM_TIMES("NetConnectivity.TCP.Fail.100B.RTT", duration);
+
+    UMA_HISTOGRAM_ENUMERATION(
+        "NetConnectivity.TCP.Status.100B", status, STATUS_MAX);
+  } else {
+    if (result == net::OK)
+      UMA_HISTOGRAM_TIMES("NetConnectivity.TCP.Success.1K.RTT", duration);
+    else
+      UMA_HISTOGRAM_TIMES("NetConnectivity.TCP.Fail.1K.RTT", duration);
+
+    UMA_HISTOGRAM_ENUMERATION(
+        "NetConnectivity.TCP.Status.1K", status, STATUS_MAX);
+  }
+
+  DoFinishCallback(result);
+
+  // Disconnect the socket so that there are no more IO operations.
+  net::TCPClientSocket* tcp_socket =
+      static_cast<net::TCPClientSocket*>(socket().get());
+  if (tcp_socket)
+    tcp_socket->Disconnect();
+
+  // We may be holding the last reference. Do not access |this| after Release().
+  Release();  // Acquired on Start().

[willchan no longer on Chromium, 2011/06/06 09:25:49]

Why is this refcounted? Who is acquiring a reference? It looks like it just
AddRef()s itself and then Release()s itself. Why not just delete itself in
Finish()?

[ramant (doing other things), 2011/06/07 20:54:00]

Done.

+}
+
+// static
+void CollectNetworkStats(const std::string& network_stats_server) {
+  if (network_stats_server.empty())
+    return;
+
+  // If we are not on IO Thread, then post a task to call CollectNetworkStats on
+  // IO Thread.
+  if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
+    BrowserThread::PostTask(
+        BrowserThread::IO,
+        FROM_HERE,
+        NewRunnableFunction(&CollectNetworkStats, network_stats_server));
+    return;
+  }
+
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  // Collect network stats is there is a network connection.

[willchan no longer on Chromium, 2011/06/06 09:25:49]

if there is

[ramant (doing other things), 2011/06/07 20:54:00]

Done.

+  if (net::NetworkChangeNotifier::IsOffline())

[willchan no longer on Chromium, 2011/06/06 09:25:49]

How often is this called? I've noticed that IsOffline() can actually block for a
few seconds on Windows while it makes an RPC call. This sucks and we need to fix
it, but it's generally only called on a network change. Or you going to be
calling this often? If so, then it could be an issue.

[ramant (doing other things), 2011/06/07 20:54:00]

We call this once in 30 mins and only when UMA upload to the server has
succeeded. We know there is a connection because UMA upload was successful. Thus
changed it to a DCHECK.

We could limit the number of times we perform the UDP test to only once by
changing kMaxNumberOfTests to 1.

Done.

+    return;
+
+  static scoped_refptr<base::FieldTrial> trial = NULL;
+  static bool collect_stats = false;
+
+  if (!trial.get()) {
+    // Set up a field trial to collect network stats for UDP and TCP.
+    base::FieldTrial::Probability kDivisor = 1000;
+
+    // Enable the connectivity testing for 0.5% of the users.
+    base::FieldTrial::Probability kProbabilityPerGroup = 5;
+
+    // After October 30, 2011 builds, it will always be in default group
+    // (disable_network_stats).
+    trial = new base::FieldTrial("NetworkConnectivity", kDivisor,
+                                 "disable_network_stats", 2011, 10, 30);
+
+    // Add option to collect_stats for NetworkConnectivity.
+    int collect_stats_group = trial->AppendGroup("collect_stats",
+                                                 kProbabilityPerGroup);
+    if (trial->group() == collect_stats_group)
+      collect_stats = true;
+  }
+
+  if (!collect_stats)
+    return;
+
+  // Run test once.
+  static const size_t kMaxNumberOfTests = INT_MAX;

[willchan no longer on Chromium, 2011/06/06 09:25:49]

No need for the static. Just let the compiler allocate this value as an
intermediate value in a register.

[ramant (doing other things), 2011/06/07 20:54:00]

Done.

+  static size_t number_of_tests_done = 0;
+
+  if (number_of_tests_done > kMaxNumberOfTests)
+    return;
+
+  ++number_of_tests_done;
+
+  scoped_refptr<UDPStatsClient> small_udp_stats(new UDPStatsClient());
+  small_udp_stats->Start(
+      network_stats_server, 6121, kSmallTestBytesToSend, NULL);

[willchan no longer on Chromium, 2011/06/06 09:25:49]

Use a named constant for 6121. Perhaps something like kUDPTestingPort. Document
that its value is not significant (or if it is significant, explain).

[ramant (doing other things), 2011/06/07 20:54:00]

Done.

+
+  scoped_refptr<UDPStatsClient> large_udp_stats(new UDPStatsClient());
+  large_udp_stats->Start(
+      network_stats_server, 6121, kLargeTestBytesToSend, NULL);
+
+  net::HostPortPair server_address(network_stats_server, 80);
+  scoped_refptr<TCPStatsClient> small_tcp_client(new TCPStatsClient());
+  small_tcp_client->Start(server_address, kSmallTestBytesToSend, NULL);
+
+  scoped_refptr<TCPStatsClient> large_tcp_client(new TCPStatsClient());
+  large_tcp_client->Start(server_address, kLargeTestBytesToSend, NULL);
+}
+
+}  // namespace chrome_browser_net