QUIC - Add Histogram to measure time difference between two packet sent in quic_connection_logger.

R=rch@chromium.org, asvitkine@chromium.org

Review URL: https://codereview.chromium.org/1348413003

Cr-Commit-Position: refs/heads/master@{#349771}

2 files changed, 13 insertions, 0 deletions

diff --git a/net/quic/quic_connection_logger.cc b/net/quic/quic_connection_logger.cc
index 5c371c61..54b6cd4 100644
--- a/net/quic/quic_connection_logger.cc
+++ b/net/quic/quic_connection_logger.cc
@@ -292,6 +292,7 @@ QuicConnectionLogger::QuicConnectionLogger(
       last_received_packet_number_(0),
       last_received_packet_size_(0),
       previous_received_packet_size_(0),
+      last_packet_sent_time_(base::TimeTicks()),
       largest_received_packet_number_(0),
       largest_received_missing_packet_number_(0),
       num_out_of_order_received_packets_(0),
@@ -456,6 +457,16 @@ void QuicConnectionLogger::OnPacketSent(
         base::Bind(&NetLogQuicPacketRetransmittedCallback,
                    original_packet_number, serialized_packet.packet_number));
   }
+  // Record time duration from last packet sent to the new packet sent.
+  if (last_packet_sent_time_.IsInitialized()) {
+    UMA_HISTOGRAM_CUSTOM_TIMES(
+        "Net.QuicTimeBetweenTwoPacketSent",
+        base::TimeDelta::FromMilliseconds(
+            sent_time.Subtract(last_packet_sent_time_).ToMilliseconds()),
+        base::TimeDelta::FromMilliseconds(1), base::TimeDelta::FromMinutes(10),
+        100);
+  }
+  last_packet_sent_time_ = sent_time;
 }
 
 void QuicConnectionLogger::OnPacketReceived(const IPEndPoint& self_address,
diff --git a/net/quic/quic_connection_logger.h b/net/quic/quic_connection_logger.h
index 1d0e62f..55e0566 100644
--- a/net/quic/quic_connection_logger.h
+++ b/net/quic/quic_connection_logger.h
@@ -126,6 +126,8 @@ class NET_EXPORT_PRIVATE QuicConnectionLogger
   size_t last_received_packet_size_;
   // The size of the previously received packet.
   size_t previous_received_packet_size_;
+  // The timestamp of last packet sent.
+  QuicTime last_packet_sent_time_;
   // The largest packet number received.  In the case where a packet is
   // received late (out of order), this value will not be updated.
   QuicPacketNumber largest_received_packet_number_;