Makes dynamic pacer select paddig target based on rate.
Today when the pacing debt is cleared, we blindly ask for 50 bytes of
padding, which is above a static magic number for RTX payload padding.
Instead, we should adjust the target size based on the current padding
rate. The old pacer sort-of does this, it allows the budget to grow up
to one process interval (usually 5ms).
This CL makes the dynamic pacer also use a duration as target, by
default 5ms to match old pacer but with a trial to allow tweaking it.
This will be important for good behavior due to
https://bugs.chromium.org/p/webrtc/issues/detail?id=11508
Bug: webrtc:10809
Change-Id: I9c14acc5730c6e2e0d7821adf5fb058b8d5487c6
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/173687
Commit-Queue: Erik Språng <sprang@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31091}
diff --git a/modules/pacing/pacing_controller_unittest.cc b/modules/pacing/pacing_controller_unittest.cc
index 3226c02..fa23da7 100644
--- a/modules/pacing/pacing_controller_unittest.cc
+++ b/modules/pacing/pacing_controller_unittest.cc
@@ -184,7 +184,9 @@
class PacingControllerTest
: public ::testing::TestWithParam<PacingController::ProcessMode> {
protected:
- PacingControllerTest() : clock_(123456) {
+ PacingControllerTest() : clock_(123456) {}
+
+ void SetUp() override {
srand(0);
// Need to initialize PacingController after we initialize clock.
pacer_ = std::make_unique<PacingController>(&clock_, &callback_, nullptr,
@@ -1983,6 +1985,46 @@
EXPECT_EQ(pacer_->NextSendTime() - clock_.CurrentTime(), kPacketPacingTime);
}
+TEST_P(PacingControllerTest, PaddingTargetAccountsForPaddingRate) {
+ if (PeriodicProcess()) {
+ // This test applies only when NOT using interval budget.
+ return;
+ }
+
+ // Re-init pacer with an explicitly set padding target of 10ms;
+ const TimeDelta kPaddingTarget = TimeDelta::Millis(10);
+ ScopedFieldTrials field_trials(
+ "WebRTC-Pacer-DynamicPaddingTarget/timedelta:10ms/");
+ SetUp();
+
+ const uint32_t kSsrc = 12345;
+ const DataRate kPacingDataRate = DataRate::KilobitsPerSec(125);
+ const DataSize kPacketSize = DataSize::Bytes(130);
+
+ uint32_t sequnce_number = 1;
+
+ // Start with pacing and padding rate equal.
+ pacer_->SetPacingRates(kPacingDataRate, kPacingDataRate);
+
+ // Send a single packet.
+ SendAndExpectPacket(RtpPacketMediaType::kVideo, kSsrc, sequnce_number++,
+ clock_.TimeInMilliseconds(), kPacketSize.bytes());
+ AdvanceTimeAndProcess();
+ ::testing::Mock::VerifyAndClearExpectations(&callback_);
+
+ size_t expected_padding_target_bytes =
+ (kPaddingTarget * kPacingDataRate).bytes();
+ EXPECT_CALL(callback_, SendPadding(expected_padding_target_bytes))
+ .WillOnce(Return(expected_padding_target_bytes));
+ AdvanceTimeAndProcess();
+
+ // Half the padding rate - expect half the padding target.
+ pacer_->SetPacingRates(kPacingDataRate, kPacingDataRate / 2);
+ EXPECT_CALL(callback_, SendPadding(expected_padding_target_bytes / 2))
+ .WillOnce(Return(expected_padding_target_bytes / 2));
+ AdvanceTimeAndProcess();
+}
+
INSTANTIATE_TEST_SUITE_P(
WithAndWithoutIntervalBudget,
PacingControllerTest,
