Report video and network stats averaged over 1s, and create corresponding UMA metrics.

remoting/client/plugin/chromoting_instance.cc

Index: remoting/client/plugin/chromoting_instance.cc
diff --git a/remoting/client/plugin/chromoting_instance.cc b/remoting/client/plugin/chromoting_instance.cc
index c32d31ded27bcd4d333f047d9af82c1536d5442a..24b30a9e91e59f0ca3d04e2e18bd795092bed831 100644
--- a/remoting/client/plugin/chromoting_instance.cc
+++ b/remoting/client/plugin/chromoting_instance.cc
@@ -32,6 +32,7 @@
 #include "ppapi/cpp/dev/url_util_dev.h"
 #include "ppapi/cpp/image_data.h"
 #include "ppapi/cpp/input_event.h"
+#include "ppapi/cpp/private/uma_private.h"
 #include "ppapi/cpp/rect.h"
 #include "ppapi/cpp/var_array_buffer.h"
 #include "ppapi/cpp/var_dictionary.h"
@@ -67,12 +68,25 @@ namespace {
 // Default DPI to assume for old clients that use notifyClientResolution.
 const int kDefaultDPI = 96;
 
-// Interval at which to sample performance statistics.
-const int kPerfStatsIntervalMs = 1000;
-
 // URL scheme used by Chrome apps and extensions.
 const char kChromeExtensionUrlScheme[] = "chrome-extension";
 
+// The boundary value for the FPS histogram: we don't expect video frame-rate to
+// be greater than 40fps. Leaving some room for future improvements, we'll set
+// the max frame rate to 60fps.
+// Histograms expect samples to be less than the boundary value, so set to 61.
+const int kMaxFrameRate = 61;
+
+// For bandwidth, based on expected real-world numbers, we'll use a histogram
+// ranging from 0 to 10MB/s, spread across 1000 buckets.

[Alexei Svitkine (slow), 2015/07/13 21:30:06]

Update comment re: # of buckets?

[anandc, 2015/07/14 19:44:22]

Done.

+// Histograms are log-scaled by default. This results in fine-grained buckets at
+// lower values and wider-ranged buckets closer to the maximum.
+// Values above the maximum defined here end up in the right-most bucket.
+// See $/src/base/metrics/histogram.h for more details.
+const int kBandwidthHistogramMin = 1;
+const int kBandwidthHistogramMax = 10240000;

[Sergey Ulanov, 2015/07/13 21:55:28]

nit: This should be either
10 MB = 10 * 1000 * 1000 B = 10000000 B
or
10 MiB = 10 * 1024 * 1024 B = 10485760 B

I'd prefer 10 MB, i.e. s/24/00/

[anandc, 2015/07/14 19:44:23]

Done.

+const int kBandwidthHistogramNumBuckets = 100;
+
 #if defined(USE_OPENSSL)
 // Size of the random seed blob used to initialize RNG in libjingle. Libjingle
 // uses the seed only for OpenSSL builds. OpenSSL needs at least 32 bytes of
@@ -728,11 +742,12 @@ void ChromotingInstance::HandleConnect(const base::DictionaryValue& data) {
   client_->Start(signal_strategy_.get(), authenticator.Pass(),
                  transport_factory.Pass(), host_jid, capabilities);
 
-  // Start timer that periodically sends perf stats.
+  // Start timers that periodically send perf stats.
   plugin_task_runner_->PostDelayedTask(
       FROM_HERE, base::Bind(&ChromotingInstance::SendPerfStats,
                             weak_factory_.GetWeakPtr()),
-      base::TimeDelta::FromMilliseconds(kPerfStatsIntervalMs));
+      base::TimeDelta::FromSeconds(
+        ChromotingStats::kStatsUpdateFrequencyInSeconds));
 }
 
 void ChromotingInstance::HandleDisconnect(const base::DictionaryValue& data) {
@@ -1052,8 +1067,12 @@ void ChromotingInstance::SendPerfStats() {
   plugin_task_runner_->PostDelayedTask(
       FROM_HERE, base::Bind(&ChromotingInstance::SendPerfStats,
                             weak_factory_.GetWeakPtr()),
-      base::TimeDelta::FromMilliseconds(kPerfStatsIntervalMs));
+      base::TimeDelta::FromSeconds(
+        ChromotingStats::kStatsUpdateFrequencyInSeconds));
 
+  // Update performance stats and send them to the client for display to users.
+  // The rate metrics are averaged over 1s, and the latency metrics are averaged
+  // over the 10 most recent samples.
   scoped_ptr<base::DictionaryValue> data(new base::DictionaryValue());
   ChromotingStats* stats = video_renderer_->GetStats();
   data->SetDouble("videoBandwidth", stats->video_bandwidth()->Rate());
@@ -1064,6 +1083,17 @@ void ChromotingInstance::SendPerfStats() {
   data->SetDouble("renderLatency", stats->video_paint_ms()->Average());
   data->SetDouble("roundtripLatency", stats->round_trip_ms()->Average());
   PostLegacyJsonMessage("onPerfStats", data.Pass());
+
+  // Upload to UMA the video frame-rate, packet-rate and bandwidth stats,
+  // averaged over 1s.
+  pp::UMAPrivate uma(this);
+  uma.HistogramEnumeration("Chromoting.Video.FrameRate",
+    stats->video_frame_rate()->Rate(), kMaxFrameRate);
+  uma.HistogramEnumeration("Chromoting.Video.PacketRate",
+    stats->video_packet_rate()->Rate(), kMaxFrameRate);
+  uma.HistogramCustomCounts("Chromoting.Video.Bandwidth",
+    stats->video_bandwidth()->Rate(), kBandwidthHistogramMin,
+    kBandwidthHistogramMax, kBandwidthHistogramNumBuckets);

[Alexei Svitkine (slow), 2015/07/13 21:30:06]

Nit: Indent is wrong. Maybe run "git cl format"

[anandc, 2015/07/14 19:44:23]

Thanks. Done.
Ran 'git cl format' and it made a fair number of edits. Going to do all of the
style-fixes in a separate CL.

 }
 
 // static