relnote: Limit the number of burst tokens in QUIC's pacing sender to the

net/quic/congestion_control/pacing_sender.cc

Index: net/quic/congestion_control/pacing_sender.cc
diff --git a/net/quic/congestion_control/pacing_sender.cc b/net/quic/congestion_control/pacing_sender.cc
index bbcae0c69a0cec157c1d789143a4f1fe61fe0c6f..c6f33efd5c4307faf24bf40c4b588275aea5f3ea 100644
--- a/net/quic/congestion_control/pacing_sender.cc
+++ b/net/quic/congestion_control/pacing_sender.cc
@@ -4,6 +4,10 @@
 
 #include "net/quic/congestion_control/pacing_sender.h"
 
+#include "net/quic/quic_flags.h"
+
+using std::min;
+
 namespace net {
 
 PacingSender::PacingSender(SendAlgorithmInterface* sender,
@@ -61,8 +65,16 @@ bool PacingSender::OnPacketSent(
     return in_flight;
   }
   if (bytes_in_flight == 0) {
-    // Add more burst tokens anytime the connection is leaving quiescence.
-    burst_tokens_ = initial_packet_burst_;
+    // Add more burst tokens anytime the connection is leaving quiescence, but
+    // limit it to the equivalent of a single bulk write, not exceeding the
+    // current CWND in packets.
+    if (FLAGS_quic_limit_pacing_burst) {
+      burst_tokens_ = min(
+          initial_packet_burst_,
+          static_cast<uint32>(sender_->GetCongestionWindow() / kDefaultTCPMSS));
+    } else {
+      burst_tokens_ = initial_packet_burst_;
+    }
   }
   if (burst_tokens_ > 0) {
     --burst_tokens_;