QUIC - Added histogram to track how often chrome sends/receives

net/quic/quic_connection_logger.cc

Index: net/quic/quic_connection_logger.cc
diff --git a/net/quic/quic_connection_logger.cc b/net/quic/quic_connection_logger.cc
index b5ca18bae7ed7389234f6e4d6e9c9c5a1104698f..22d820ad2c02804041c67e2ca95fe4831144090f 100644
--- a/net/quic/quic_connection_logger.cc
+++ b/net/quic/quic_connection_logger.cc
@@ -29,11 +29,25 @@ namespace net {
 
 namespace {
 
+// Histograms to track how often chrome sends/receives flow-control BLOCKED
+// frames. Note: these values must be kept in sync with the corresponding values
+// in: tools/metrics/histograms/histograms.xml
+enum BlockedFrameType {
+  BLOCKED_FRAME_RECEIVED = 0,
+  BLOCKED_FRAME_SENT = 1,
+  NUM_BLOCKED_FRAMES = 2,
+};
+
 // We have ranges-of-buckets in the cumulative histogram (covering 21 packet
 // sequences) of length 2, 3, 4, ... 22.
 // Hence the largest sample is bounded by the sum of those numbers.
 const int kBoundingSampleInCumulativeHistogram = ((2 + 22) * 21) / 2;
 
+void RecordBlockedFrame(BlockedFrameType blocked_frame_type) {
+  UMA_HISTOGRAM_ENUMERATION("Net.QuicSession.FlowControlBlockedFrame",
+                            blocked_frame_type, NUM_BLOCKED_FRAMES);

[Ryan Hamilton, 2014/10/21 19:48:14]

Instead of recording entry each time we become blocked, I wonder if it would be
more useful to record, say, the number of total blocked frames sent/received
when a connection is finished?

[ramant (doing other things), 2014/10/21 22:05:31]

Done.

+}
+
 base::Value* NetLogQuicPacketCallback(const IPEndPoint* self_address,
                                       const IPEndPoint* peer_address,
                                       size_t packet_size,
@@ -442,6 +456,7 @@ void QuicConnectionLogger::OnFrameAddedToPacket(const QuicFrame& frame) {
                      frame.window_update_frame));
       break;
     case BLOCKED_FRAME:
+      RecordBlockedFrame(BLOCKED_FRAME_SENT);
       net_log_.AddEvent(
           NetLog::TYPE_QUIC_SESSION_BLOCKED_FRAME_SENT,
           base::Bind(&NetLogQuicBlockedFrameCallback,
@@ -636,6 +651,7 @@ void QuicConnectionLogger::OnWindowUpdateFrame(
 }
 
 void QuicConnectionLogger::OnBlockedFrame(const QuicBlockedFrame& frame) {
+  RecordBlockedFrame(BLOCKED_FRAME_RECEIVED);
   net_log_.AddEvent(
       NetLog::TYPE_QUIC_SESSION_BLOCKED_FRAME_RECEIVED,
       base::Bind(&NetLogQuicBlockedFrameCallback, &frame));