Add a new Net.AlternateProtocolUsage for tracking usage of Alternate-Protocol.

BUG=

Review URL: https://codereview.chromium.org/232193002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@263298 0039d316-1c4b-4281-b951-d872f2087c98

8 files changed, 83 insertions, 5 deletions

diff --git a/net/http/http_server_properties.cc b/net/http/http_server_properties.cc
index a10d506..e714d9f 100644
--- a/net/http/http_server_properties.cc
+++ b/net/http/http_server_properties.cc
@@ -5,6 +5,7 @@
 #include "net/http/http_server_properties.h"
 
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "base/strings/stringprintf.h"
 
 namespace net {
@@ -31,6 +32,11 @@ COMPILE_ASSERT(
 
 }  // namespace
 
+void HistogramAlternateProtocolUsage(AlternateProtocolUsage usage) {
+  UMA_HISTOGRAM_ENUMERATION("Net.AlternateProtocolUsage", usage,
+                            ALTERNATE_PROTOCOL_USAGE_MAX);
+}
+
 bool IsAlternateProtocolValid(AlternateProtocol protocol) {
   return protocol >= ALTERNATE_PROTOCOL_MINIMUM_VALID_VERSION &&
       protocol <= ALTERNATE_PROTOCOL_MAXIMUM_VALID_VERSION;
diff --git a/net/http/http_server_properties.h b/net/http/http_server_properties.h
index b988e9f..3d12d02 100644
--- a/net/http/http_server_properties.h
+++ b/net/http/http_server_properties.h
@@ -19,6 +19,26 @@
 
 namespace net {
 
+enum AlternateProtocolUsage {
+  // Alternate Protocol was used without racing a normal connection.
+  ALTERNATE_PROTOCOL_USAGE_NO_RACE = 0,
+  // Alternate Protocol was used by winning a race with a normal connection.
+  ALTERNATE_PROTOCOL_USAGE_WON_RACE = 1,
+  // Alternate Protocol was not used by losing a race with a normal connection.
+  ALTERNATE_PROTOCOL_USAGE_LOST_RACE = 2,
+  // Alternate Protocol was not used because no Alternate-Protocol information
+  // was available when the request was issued, but an Alternate-Protocol header
+  // was present in the response.
+  ALTERNATE_PROTOCOL_USAGE_MAPPING_MISSING = 3,
+  // Alternate Protocol was not used because it was marked broken.
+  ALTERNATE_PROTOCOL_USAGE_BROKEN = 4,
+  // Maximum value for the enum.
+  ALTERNATE_PROTOCOL_USAGE_MAX,
+};
+
+// Log a histogram to reflect |usage|.
+NET_EXPORT void HistogramAlternateProtocolUsage(AlternateProtocolUsage usage);
+
 enum AlternateProtocol {
   DEPRECATED_NPN_SPDY_2 = 0,
   ALTERNATE_PROTOCOL_MINIMUM_VALID_VERSION = DEPRECATED_NPN_SPDY_2,
diff --git a/net/http/http_server_properties_impl.cc b/net/http/http_server_properties_impl.cc
index 7fb4205..4550427 100644
--- a/net/http/http_server_properties_impl.cc
+++ b/net/http/http_server_properties_impl.cc
@@ -258,6 +258,11 @@ void HttpServerPropertiesImpl::SetAlternateProtocol(
                    << ", Protocol: " << alternate_protocol
                    << "].";
     }
+  } else {
+    // TODO(rch): Consider the case where multiple requests are started
+    // before the first completes. In this case, only one of the jobs
+    // would reach this code, whereas all of them should should have.
+    HistogramAlternateProtocolUsage(ALTERNATE_PROTOCOL_USAGE_MAPPING_MISSING);
   }
 
   alternate_protocol_map_.Put(server, alternate);
diff --git a/net/http/http_stream_factory_impl.cc b/net/http/http_stream_factory_impl.cc
index 991e469..7500373 100644
--- a/net/http/http_stream_factory_impl.cc
+++ b/net/http/http_stream_factory_impl.cc
@@ -206,8 +206,10 @@ PortAlternateProtocolPair HttpStreamFactoryImpl::GetAlternateProtocolRequestFor(
 
   PortAlternateProtocolPair alternate =
       http_server_properties.GetAlternateProtocol(origin);
-  if (alternate.protocol == ALTERNATE_PROTOCOL_BROKEN)
+  if (alternate.protocol == ALTERNATE_PROTOCOL_BROKEN) {
+    HistogramAlternateProtocolUsage(ALTERNATE_PROTOCOL_USAGE_BROKEN);
     return kNoAlternateProtocol;
+  }
 
   if (!IsAlternateProtocolValid(alternate.protocol)) {
     NOTREACHED();
diff --git a/net/http/http_stream_factory_impl_job.cc b/net/http/http_stream_factory_impl_job.cc
index 9feb3b7..7a8a52e 100644
--- a/net/http/http_stream_factory_impl_job.cc
+++ b/net/http/http_stream_factory_impl_job.cc
@@ -98,6 +98,7 @@ HttpStreamFactoryImpl::Job::Job(HttpStreamFactoryImpl* stream_factory,
       using_spdy_(false),
       using_quic_(false),
       quic_request_(session_->quic_stream_factory()),
+      using_existing_quic_session_(false),
       force_spdy_always_(HttpStreamFactory::force_spdy_always()),
       force_spdy_over_ssl_(HttpStreamFactory::force_spdy_over_ssl()),
       spdy_certificate_error_(OK),
@@ -750,7 +751,9 @@ int HttpStreamFactoryImpl::Job::DoInitConnection() {
     int rv = quic_request_.Request(
         destination, secure_quic, request_info_.privacy_mode,
         request_info_.method, net_log_, io_callback_);
-    if (rv != OK) {
+    if (rv == OK) {
+      using_existing_quic_session_ = true;
+    } else {
       // OK, there's no available QUIC session. Let |waiting_job_| resume
       // if it's paused.
       if (waiting_job_) {
@@ -1447,6 +1450,21 @@ bool HttpStreamFactoryImpl::Job::IsOrphaned() const {
   return !IsPreconnecting() && !request_;
 }
 
+void HttpStreamFactoryImpl::Job::ReportJobSuccededForRequest() {
+  if (using_existing_quic_session_) {
+    // If an existing session was used, then no TCP connection was
+    // started.
+    HistogramAlternateProtocolUsage(ALTERNATE_PROTOCOL_USAGE_NO_RACE);
+  } else if (original_url_) {
+    // This job was the alternate protocol job, and hence won the race.
+    HistogramAlternateProtocolUsage(ALTERNATE_PROTOCOL_USAGE_WON_RACE);
+  } else {
+    // This job was the normal job, and hence the alternate protocol job lost
+    // the race.
+    HistogramAlternateProtocolUsage(ALTERNATE_PROTOCOL_USAGE_LOST_RACE);
+  }
+}
+
 bool HttpStreamFactoryImpl::Job::IsRequestEligibleForPipelining() {
   if (IsPreconnecting() || !request_) {
     return false;
diff --git a/net/http/http_stream_factory_impl_job.h b/net/http/http_stream_factory_impl_job.h
index 1970b5b..d440647 100644
--- a/net/http/http_stream_factory_impl_job.h
+++ b/net/http/http_stream_factory_impl_job.h
@@ -92,6 +92,10 @@ class HttpStreamFactoryImpl::Job {
   // Indicates whether or not this Job has been orphaned by a Request.
   bool IsOrphaned() const;
 
+  // Called to indicate that this job succeeded, and some other jobs
+  // will be orphaned.
+  void ReportJobSuccededForRequest();
+
  private:
   enum State {
     STATE_START,
@@ -277,6 +281,9 @@ class HttpStreamFactoryImpl::Job {
   bool using_quic_;
   QuicStreamRequest quic_request_;
 
+  // True if this job used an existing QUIC session.
+  bool using_existing_quic_session_;
+
   // Force spdy for all connections.
   bool force_spdy_always_;
 
diff --git a/net/http/http_stream_factory_impl_request.cc b/net/http/http_stream_factory_impl_request.cc
index 5f129ac..1eb8e51 100644
--- a/net/http/http_stream_factory_impl_request.cc
+++ b/net/http/http_stream_factory_impl_request.cc
@@ -380,13 +380,17 @@ void HttpStreamFactoryImpl::Request::OnJobSucceeded(Job* job) {
     // they complete? Or do we want to prevent connecting a new SpdySession if
     // we've already got one available for a different hostname where the ip
     // address matches up?
-  } else if (!bound_job_.get()) {
+    return;
+  }
+  if (!bound_job_.get()) {
+    if (jobs_.size() > 1)
+      job->ReportJobSuccededForRequest();
     // We may have other jobs in |jobs_|. For example, if we start multiple jobs
     // for Alternate-Protocol.
     OrphanJobsExcept(job);
-  } else {
-    DCHECK(jobs_.empty());
+    return;
   }
+  DCHECK(jobs_.empty());
 }
 
 }  // namespace net
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 9bc2786..f0db3dc 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -10466,6 +10466,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <summary>The scheme of the URL for each main-frame navigation.</summary>
 </histogram>
 
+<histogram name="Net.AlternateProtocolUsage" enum="AlternateProtocolUsage">
+  <owner>rch@chromium.org</owner>
+  <summary>
+    Breakdown of how requests which could potentially make use of an alternate
+    protocol use or don't use the protocol.
+  </summary>
+</histogram>
+
 <histogram name="Net.AsyncResourceHandler_PendingDataCount">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <summary>
@@ -30097,6 +30105,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="4" label="Snapped"/>
 </enum>
 
+<enum name="AlternateProtocolUsage" type="int">
+  <int value="0" label="ALTERNATE_PROTOCOL_USAGE_NO_RACE"/>
+  <int value="1" label="ALTERNATE_PROTOCOL_USAGE_WON_RACE"/>
+  <int value="2" label="ALTERNATE_PROTOCOL_USAGE_LOST_RACE"/>
+  <int value="3" label="ALTERNATE_PROTOCOL_USAGE_MAPPING_MISSING"/>
+  <int value="4" label="ALTERNATE_PROTOCOL_USAGE_BROKEN"/>
+</enum>
+
 <enum name="AndroidActivityId" type="int">
   <int value="1" label="Unknown"/>
   <int value="2" label="Main"/>