commit be29b9ed0476c615e3e1c593f6dffb967495ca3a
author wub <wub@google.com> Sun Nov 24 06:56:04 2019 -0800
committer Copybara-Service <copybara-worker@google.com> Sun Nov 24 06:56:50 2019 -0800
tree 4b77ac99ff6e7736120d17eedbef024e4a1a7e5a
parent a89eee38756967553cd5b406ba7a1a14e8df9de5

gfe-relnote: Refactor how QuicConnectionStats.slowstart_duration is calculated in QUIC BBR1, and start populate it in QUIC BBR2. Not protected. (Worst case we get some incorrect values in transport connection stats)

Similar to slowstart_duration, I will add drain_duration, probe_rtt_duration, probe_bw_(down|up|cruise)_duration, in a follow up CL.

PiperOrigin-RevId: 282224334
Change-Id: I873c39dcd47eb03d22d245cdfbf13aabc1a814e6

quic/core/congestion_control/bbr_sender.cc

diff --git a/quic/core/congestion_control/bbr_sender.cc b/quic/core/congestion_control/bbr_sender.cc
index 93ee5cb..4217048 100644
--- a/quic/core/congestion_control/bbr_sender.cc
+++ b/quic/core/congestion_control/bbr_sender.cc
@@ -11,6 +11,7 @@
 #include "net/third_party/quiche/src/quic/core/congestion_control/rtt_stats.h"
 #include "net/third_party/quiche/src/quic/core/crypto/crypto_protocol.h"
 #include "net/third_party/quiche/src/quic/core/quic_time.h"
+#include "net/third_party/quiche/src/quic/core/quic_time_accumulator.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_bug_tracker.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_fallthrough.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_flag_utils.h"
@@ -136,8 +137,10 @@
       app_limited_since_last_probe_rtt_(false),
       min_rtt_since_last_probe_rtt_(QuicTime::Delta::Infinite()) {
   if (stats_) {
+    // Clear some startup stats if |stats_| has been used by another sender,
+    // which happens e.g. when QuicConnection switch send algorithms.
     stats_->slowstart_count = 0;
-    stats_->slowstart_start_time = QuicTime::Zero();
+    stats_->slowstart_duration = QuicTimeAccumulator();
   }
   EnterStartupMode(now);
 }
@@ -465,8 +468,7 @@
 void BbrSender::EnterStartupMode(QuicTime now) {
   if (stats_) {
     ++stats_->slowstart_count;
-    DCHECK_EQ(stats_->slowstart_start_time, QuicTime::Zero()) << mode_;
-    stats_->slowstart_start_time = now;
+    stats_->slowstart_duration.Start(now);
   }
   mode_ = STARTUP;
   pacing_gain_ = high_gain_;
@@ -671,12 +673,7 @@
 void BbrSender::OnExitStartup(QuicTime now) {
   DCHECK_EQ(mode_, STARTUP);
   if (stats_) {
-    DCHECK_NE(stats_->slowstart_start_time, QuicTime::Zero());
-    if (now > stats_->slowstart_start_time) {
-      stats_->slowstart_duration =
-          now - stats_->slowstart_start_time + stats_->slowstart_duration;
-    }
-    stats_->slowstart_start_time = QuicTime::Zero();
+    stats_->slowstart_duration.Stop(now);
   }
 }