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Commit e9dcf79f authored by Ady Abraham's avatar Ady Abraham
Browse files

SF: do not skip a frame if it will not cause backpressure on dvrr 

Bug: 340633280
Test: android.platform.test.scenario.sysui.people.PeopleSpaceActivityMicrobenchmark#startPeopleSpaceActivity
Change-Id: If230ef0ab2f8ac3846e4e3701e51d1821192548c
parent 9325608d

services/surfaceflinger/Scheduler/VSyncPredictor.cpp

+27 −23
Original line number Diff line number Diff line
@@ -650,21 +650,24 @@ std::optional<TimePoint> VSyncPredictor::VsyncTimeline::nextAnticipatedVSyncTime 
    const auto threshold = model.slope / 2;

    const auto lastFrameMissed =

            lastVsyncOpt && std::abs(*lastVsyncOpt - missedVsync.vsync.ns()) < threshold;

    if (FlagManager::getInstance().vrr_config() && lastFrameMissed) {

        // If the last frame missed is the last vsync, we already shifted the timeline. Depends on

        // whether we skipped the frame (onFrameMissed) or not (onFrameBegin) we apply a different

        // fixup. There is no need to to shift the vsync timeline again.

    const auto mightBackpressure = minFramePeriodOpt && mRenderRateOpt &&

            mRenderRateOpt->getPeriod() < 2 * (*minFramePeriodOpt);

    if (FlagManager::getInstance().vrr_config()) {

        if (lastFrameMissed) {

            // If the last frame missed is the last vsync, we already shifted the timeline. Depends

            // on whether we skipped the frame (onFrameMissed) or not (onFrameBegin) we apply a

            // different fixup. There is no need to to shift the vsync timeline again.

            vsyncTime += missedVsync.fixup.ns();

            ATRACE_FORMAT_INSTANT("lastFrameMissed");

    } else if (FlagManager::getInstance().vrr_config() && minFramePeriodOpt && mRenderRateOpt &&

               lastVsyncOpt) {

        } else if (mightBackpressure && lastVsyncOpt) {

            // lastVsyncOpt is based on the old timeline before we shifted it. we should correct it

            // first before trying to use it.

            lastVsyncOpt = snapToVsyncAlignedWithRenderRate(model, *lastVsyncOpt);

            const auto vsyncDiff = vsyncTime - *lastVsyncOpt;

            if (vsyncDiff <= minFramePeriodOpt->ns() - threshold) {

                // avoid a duplicate vsync

            ATRACE_FORMAT_INSTANT("skipping a vsync to avoid duplicate frame. next in %.2f which "

                ATRACE_FORMAT_INSTANT("skipping a vsync to avoid duplicate frame. next in %.2f "

                                      "which "

                                      "is %.2f "

                                      "from "

                                      "prev. "
@@ -675,6 +678,7 @@ std::optional<TimePoint> VSyncPredictor::VsyncTimeline::nextAnticipatedVSyncTime 
                vsyncTime += mRenderRateOpt->getPeriodNsecs();

            }

        }

    }



    ATRACE_FORMAT_INSTANT("vsync in %.2fms", float(vsyncTime - TimePoint::now().ns()) / 1e6f);

    if (mValidUntil && vsyncTime > mValidUntil->ns()) {