Reland "SF: Encapsulate frame targeting"
Introduce FrameTargeter to isolate a display's per-frame metrics around
past/upcoming deadline targets. The Scheduler updates the FrameTargeter
on frame begin/end, whereas ICompositor (concretely SurfaceFlinger) has
read-only access via the FrameTarget interface.
For now, only instantiate the pacesetter's FrameTargeter.
The reverted Idf9f43b37f3479c94a478d154eaa46f43e0c6c9d had an incorrect
functional change that adjusted `earliestPresentTime` based on the past
VSYNC, which differs from the previous frame's VSYNC when targeting two
VSYNCs ahead. This CL restores the `earliestPresentTime` to be relative
to the previous frame.
Bug: 262269033
Bug: 241285475
Bug: 241285191
Test: Perfetto
Test: dumpsys SurfaceFlinger --scheduler
Test: atest libscheduler_test:FrameTargeterTest
Test: systemui-bubble-1-jank-suite on raven-userdebug
Change-Id: I584e299e8af55baae1125f45fd47b13f705a268c
diff --git a/services/surfaceflinger/Scheduler/src/FrameTargeter.cpp b/services/surfaceflinger/Scheduler/src/FrameTargeter.cpp
new file mode 100644
index 0000000..7138afd
--- /dev/null
+++ b/services/surfaceflinger/Scheduler/src/FrameTargeter.cpp
@@ -0,0 +1,152 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gui/TraceUtils.h>
+
+#include <scheduler/FrameTargeter.h>
+#include <scheduler/IVsyncSource.h>
+
+namespace android::scheduler {
+
+TimePoint FrameTarget::pastVsyncTime(Period vsyncPeriod) const {
+ // TODO(b/267315508): Generalize to N VSYNCs.
+ const int shift = static_cast<int>(targetsVsyncsAhead<2>(vsyncPeriod));
+ return mExpectedPresentTime - Period::fromNs(vsyncPeriod.ns() << shift);
+}
+
+const FenceTimePtr& FrameTarget::presentFenceForPastVsync(Period vsyncPeriod) const {
+ // TODO(b/267315508): Generalize to N VSYNCs.
+ const size_t i = static_cast<size_t>(targetsVsyncsAhead<2>(vsyncPeriod));
+ return mPresentFences[i].fenceTime;
+}
+
+bool FrameTarget::wouldPresentEarly(Period vsyncPeriod) const {
+ // TODO(b/241285475): Since this is called during `composite`, the calls to `targetsVsyncsAhead`
+ // should use `TimePoint::now()` in case of delays since `mFrameBeginTime`.
+
+ // TODO(b/267315508): Generalize to N VSYNCs.
+ if (targetsVsyncsAhead<3>(vsyncPeriod)) {
+ return true;
+ }
+
+ const auto fence = presentFenceForPastVsync(vsyncPeriod);
+ return fence->isValid() && fence->getSignalTime() != Fence::SIGNAL_TIME_PENDING;
+}
+
+void FrameTargeter::beginFrame(const BeginFrameArgs& args, const IVsyncSource& vsyncSource) {
+ return beginFrame(args, vsyncSource, &FrameTargeter::isFencePending);
+}
+
+void FrameTargeter::beginFrame(const BeginFrameArgs& args, const IVsyncSource& vsyncSource,
+ IsFencePendingFuncPtr isFencePendingFuncPtr) {
+ mVsyncId = args.vsyncId;
+ mFrameBeginTime = args.frameBeginTime;
+
+ // The `expectedVsyncTime`, which was predicted when this frame was scheduled, is normally in
+ // the future relative to `frameBeginTime`, but may not be for delayed frames. Adjust
+ // `mExpectedPresentTime` accordingly, but not `mScheduledPresentTime`.
+ const TimePoint lastScheduledPresentTime = mScheduledPresentTime;
+ mScheduledPresentTime = args.expectedVsyncTime;
+
+ const Period vsyncPeriod = vsyncSource.period();
+
+ // Calculate the expected present time once and use the cached value throughout this frame to
+ // make sure all layers are seeing this same value.
+ if (args.expectedVsyncTime >= args.frameBeginTime) {
+ mExpectedPresentTime = args.expectedVsyncTime;
+ } else {
+ mExpectedPresentTime = vsyncSource.vsyncDeadlineAfter(args.frameBeginTime);
+ if (args.sfWorkDuration > vsyncPeriod) {
+ // Inflate the expected present time if we're targeting the next VSYNC.
+ mExpectedPresentTime += vsyncPeriod;
+ }
+ }
+
+ ATRACE_FORMAT("%s %" PRId64 " vsyncIn %.2fms%s", __func__, ftl::to_underlying(args.vsyncId),
+ ticks<std::milli, float>(mExpectedPresentTime - TimePoint::now()),
+ mExpectedPresentTime == args.expectedVsyncTime ? "" : " (adjusted)");
+
+ const FenceTimePtr& pastPresentFence = presentFenceForPastVsync(vsyncPeriod);
+
+ // In cases where the present fence is about to fire, give it a small grace period instead of
+ // giving up on the frame.
+ //
+ // TODO(b/280667110): The grace period should depend on `sfWorkDuration` and `vsyncPeriod` being
+ // approximately equal, not whether backpressure propagation is enabled.
+ const int graceTimeForPresentFenceMs = static_cast<int>(
+ mBackpressureGpuComposition || !mCompositionCoverage.test(CompositionCoverage::Gpu));
+
+ // Pending frames may trigger backpressure propagation.
+ const auto& isFencePending = *isFencePendingFuncPtr;
+ mFramePending = pastPresentFence != FenceTime::NO_FENCE &&
+ isFencePending(pastPresentFence, graceTimeForPresentFenceMs);
+
+ // A frame is missed if the prior frame is still pending. If no longer pending, then we still
+ // count the frame as missed if the predicted present time was further in the past than when the
+ // fence actually fired. Add some slop to correct for drift. This should generally be smaller
+ // than a typical frame duration, but should not be so small that it reports reasonable drift as
+ // a missed frame.
+ mFrameMissed = mFramePending || [&] {
+ const nsecs_t pastPresentTime = pastPresentFence->getSignalTime();
+ if (pastPresentTime < 0) return false;
+ const nsecs_t frameMissedSlop = vsyncPeriod.ns() / 2;
+ return lastScheduledPresentTime.ns() < pastPresentTime - frameMissedSlop;
+ }();
+
+ mHwcFrameMissed = mFrameMissed && mCompositionCoverage.test(CompositionCoverage::Hwc);
+ mGpuFrameMissed = mFrameMissed && mCompositionCoverage.test(CompositionCoverage::Gpu);
+
+ if (mFrameMissed) mFrameMissedCount++;
+ if (mHwcFrameMissed) mHwcFrameMissedCount++;
+ if (mGpuFrameMissed) mGpuFrameMissedCount++;
+}
+
+void FrameTargeter::endFrame(const CompositeResult& result) {
+ mCompositionCoverage = result.compositionCoverage;
+}
+
+FenceTimePtr FrameTargeter::setPresentFence(sp<Fence> presentFence) {
+ auto presentFenceTime = std::make_shared<FenceTime>(presentFence);
+ return setPresentFence(std::move(presentFence), std::move(presentFenceTime));
+}
+
+FenceTimePtr FrameTargeter::setPresentFence(sp<Fence> presentFence, FenceTimePtr presentFenceTime) {
+ mPresentFences[1] = mPresentFences[0];
+ mPresentFences[0] = {std::move(presentFence), presentFenceTime};
+ return presentFenceTime;
+}
+
+void FrameTargeter::dump(utils::Dumper& dumper) const {
+ using namespace std::string_view_literals;
+
+ utils::Dumper::Section section(dumper, "Frame Targeting"sv);
+
+ // There are scripts and tests that expect this (rather than "name=value") format.
+ dumper.dump({}, "Total missed frame count: " + std::to_string(mFrameMissedCount));
+ dumper.dump({}, "HWC missed frame count: " + std::to_string(mHwcFrameMissedCount));
+ dumper.dump({}, "GPU missed frame count: " + std::to_string(mGpuFrameMissedCount));
+}
+
+bool FrameTargeter::isFencePending(const FenceTimePtr& fence, int graceTimeMs) {
+ ATRACE_CALL();
+ const status_t status = fence->wait(graceTimeMs);
+
+ // This is the same as Fence::Status::Unsignaled, but it saves a call to getStatus,
+ // which calls wait(0) again internally.
+ return status == -ETIME;
+}
+
+} // namespace android::scheduler