Project import generated by Copybara.
PiperOrigin-RevId: 237361882
Change-Id: I109a68f44db867b20f8c6a7732b0ce657133e52a
diff --git a/quic/core/congestion_control/prr_sender_test.cc b/quic/core/congestion_control/prr_sender_test.cc
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+++ b/quic/core/congestion_control/prr_sender_test.cc
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+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/third_party/quiche/src/quic/core/congestion_control/prr_sender.h"
+
+#include <algorithm>
+
+#include "net/third_party/quiche/src/quic/core/crypto/crypto_protocol.h"
+#include "net/third_party/quiche/src/quic/core/quic_constants.h"
+#include "net/third_party/quiche/src/quic/platform/api/quic_test.h"
+
+namespace quic {
+namespace test {
+
+namespace {
+// Constant based on TCP defaults.
+const QuicByteCount kMaxSegmentSize = kDefaultTCPMSS;
+} // namespace
+
+class PrrSenderTest : public QuicTest {};
+
+TEST_F(PrrSenderTest, SingleLossResultsInSendOnEveryOtherAck) {
+ PrrSender prr;
+ QuicPacketCount num_packets_in_flight = 50;
+ QuicByteCount bytes_in_flight = num_packets_in_flight * kMaxSegmentSize;
+ const QuicPacketCount ssthresh_after_loss = num_packets_in_flight / 2;
+ const QuicByteCount congestion_window = ssthresh_after_loss * kMaxSegmentSize;
+
+ prr.OnPacketLost(bytes_in_flight);
+ // Ack a packet. PRR allows one packet to leave immediately.
+ prr.OnPacketAcked(kMaxSegmentSize);
+ bytes_in_flight -= kMaxSegmentSize;
+ EXPECT_TRUE(prr.CanSend(congestion_window, bytes_in_flight,
+ ssthresh_after_loss * kMaxSegmentSize));
+ // Send retransmission.
+ prr.OnPacketSent(kMaxSegmentSize);
+ // PRR shouldn't allow sending any more packets.
+ EXPECT_FALSE(prr.CanSend(congestion_window, bytes_in_flight,
+ ssthresh_after_loss * kMaxSegmentSize));
+
+ // One packet is lost, and one ack was consumed above. PRR now paces
+ // transmissions through the remaining 48 acks. PRR will alternatively
+ // disallow and allow a packet to be sent in response to an ack.
+ for (uint64_t i = 0; i < ssthresh_after_loss - 1; ++i) {
+ // Ack a packet. PRR shouldn't allow sending a packet in response.
+ prr.OnPacketAcked(kMaxSegmentSize);
+ bytes_in_flight -= kMaxSegmentSize;
+ EXPECT_FALSE(prr.CanSend(congestion_window, bytes_in_flight,
+ ssthresh_after_loss * kMaxSegmentSize));
+ // Ack another packet. PRR should now allow sending a packet in response.
+ prr.OnPacketAcked(kMaxSegmentSize);
+ bytes_in_flight -= kMaxSegmentSize;
+ EXPECT_TRUE(prr.CanSend(congestion_window, bytes_in_flight,
+ ssthresh_after_loss * kMaxSegmentSize));
+ // Send a packet in response.
+ prr.OnPacketSent(kMaxSegmentSize);
+ bytes_in_flight += kMaxSegmentSize;
+ }
+
+ // Since bytes_in_flight is now equal to congestion_window, PRR now maintains
+ // packet conservation, allowing one packet to be sent in response to an ack.
+ EXPECT_EQ(congestion_window, bytes_in_flight);
+ for (int i = 0; i < 10; ++i) {
+ // Ack a packet.
+ prr.OnPacketAcked(kMaxSegmentSize);
+ bytes_in_flight -= kMaxSegmentSize;
+ EXPECT_TRUE(prr.CanSend(congestion_window, bytes_in_flight,
+ ssthresh_after_loss * kMaxSegmentSize));
+ // Send a packet in response, since PRR allows it.
+ prr.OnPacketSent(kMaxSegmentSize);
+ bytes_in_flight += kMaxSegmentSize;
+
+ // Since bytes_in_flight is equal to the congestion_window,
+ // PRR disallows sending.
+ EXPECT_EQ(congestion_window, bytes_in_flight);
+ EXPECT_FALSE(prr.CanSend(congestion_window, bytes_in_flight,
+ ssthresh_after_loss * kMaxSegmentSize));
+ }
+}
+
+TEST_F(PrrSenderTest, BurstLossResultsInSlowStart) {
+ PrrSender prr;
+ QuicByteCount bytes_in_flight = 20 * kMaxSegmentSize;
+ const QuicPacketCount num_packets_lost = 13;
+ const QuicPacketCount ssthresh_after_loss = 10;
+ const QuicByteCount congestion_window = ssthresh_after_loss * kMaxSegmentSize;
+
+ // Lose 13 packets.
+ bytes_in_flight -= num_packets_lost * kMaxSegmentSize;
+ prr.OnPacketLost(bytes_in_flight);
+
+ // PRR-SSRB will allow the following 3 acks to send up to 2 packets.
+ for (int i = 0; i < 3; ++i) {
+ prr.OnPacketAcked(kMaxSegmentSize);
+ bytes_in_flight -= kMaxSegmentSize;
+ // PRR-SSRB should allow two packets to be sent.
+ for (int j = 0; j < 2; ++j) {
+ EXPECT_TRUE(prr.CanSend(congestion_window, bytes_in_flight,
+ ssthresh_after_loss * kMaxSegmentSize));
+ // Send a packet in response.
+ prr.OnPacketSent(kMaxSegmentSize);
+ bytes_in_flight += kMaxSegmentSize;
+ }
+ // PRR should allow no more than 2 packets in response to an ack.
+ EXPECT_FALSE(prr.CanSend(congestion_window, bytes_in_flight,
+ ssthresh_after_loss * kMaxSegmentSize));
+ }
+
+ // Out of SSRB mode, PRR allows one send in response to each ack.
+ for (int i = 0; i < 10; ++i) {
+ prr.OnPacketAcked(kMaxSegmentSize);
+ bytes_in_flight -= kMaxSegmentSize;
+ EXPECT_TRUE(prr.CanSend(congestion_window, bytes_in_flight,
+ ssthresh_after_loss * kMaxSegmentSize));
+ // Send a packet in response.
+ prr.OnPacketSent(kMaxSegmentSize);
+ bytes_in_flight += kMaxSegmentSize;
+ }
+}
+
+} // namespace test
+} // namespace quic
