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Commit 1c7938ec authored by Alec Mouri's avatar Alec Mouri
Browse files

Support injecting jank into Scheduler for testing purposes 

Injects a fraction of a frame's expected present time as a jank. This is
mainly to avoid thinking about hard-coding milliseconds.

Also supports delaying this jank injection, since the Perfetto UI
currently steals any ADB session

Bug: 296636083
Test: TouchLatency + perfetto
Change-Id: If08616e68c3e7b3d6eaed6f6ff5cbc6ad444481e
parent c6e03916

services/surfaceflinger/Scheduler/Scheduler.cpp

+11 −0
Original line number Diff line number Diff line
@@ -211,6 +211,17 @@ void Scheduler::onFrameSignal(ICompositor& compositor, VsyncId vsyncId, 
        targeters.try_emplace(id, &targeter);

    }



    if (flagutils::vrrConfigEnabled() &&

        CC_UNLIKELY(mPacesetterFrameDurationFractionToSkip > 0.f)) {

        const auto period = pacesetterTargeter.target().expectedFrameDuration();

        const auto skipDuration = Duration::fromNs(

                static_cast<nsecs_t>(period.ns() * mPacesetterFrameDurationFractionToSkip));

        ATRACE_FORMAT("Injecting jank for %f%% of the frame (%" PRId64 " ns)",

                      mPacesetterFrameDurationFractionToSkip * 100, skipDuration.ns());

        std::this_thread::sleep_for(skipDuration);

        mPacesetterFrameDurationFractionToSkip = 0.f;

    }



    const auto resultsPerDisplay = compositor.composite(pacesetterId, targeters);

    compositor.sample();

services/surfaceflinger/Scheduler/Scheduler.h

+8 −0
Original line number Diff line number Diff line
@@ -323,6 +323,11 @@ public: 
        return mFeatures.test(Feature::kSmallDirtyContentDetection);

    }



    // Injects a delay that is a fraction of the predicted frame duration for the next frame.

    void injectPacesetterDelay(float frameDurationFraction) REQUIRES(kMainThreadContext) {

        mPacesetterFrameDurationFractionToSkip = frameDurationFraction;

    }



private:

    friend class TestableScheduler;
@@ -452,6 +457,9 @@ private: 
    // Timer used to monitor display power mode.

    ftl::Optional<OneShotTimer> mDisplayPowerTimer;



    // Injected delay prior to compositing, for simulating jank.

    float mPacesetterFrameDurationFractionToSkip GUARDED_BY(kMainThreadContext) = 0.f;



    ISchedulerCallback& mSchedulerCallback;



    // mDisplayLock may be locked while under mPolicyLock.

services/surfaceflinger/SurfaceFlinger.cpp

+35 −2
Original line number Diff line number Diff line
@@ -6660,9 +6660,9 @@ status_t SurfaceFlinger::CheckTransactCodeCredentials(uint32_t code) { 
        code == IBinder::SYSPROPS_TRANSACTION) {

        return OK;

    }

    // Numbers from 1000 to 1044 are currently used for backdoors. The code

    // Numbers from 1000 to 1045 are currently used for backdoors. The code

    // in onTransact verifies that the user is root, and has access to use SF.

    if (code >= 1000 && code <= 1044) {

    if (code >= 1000 && code <= 1045) {

        ALOGV("Accessing SurfaceFlinger through backdoor code: %u", code);

        return OK;

    }
@@ -7151,6 +7151,39 @@ status_t SurfaceFlinger::onTransact(uint32_t code, const Parcel& data, Parcel* r 
                }

                return NO_ERROR;

            }

            // Inject jank

            // First argument is a float that describes the fraction of frame duration to jank by.

            // Second argument is a delay in ms for triggering the jank. This is useful for working

            // with tools that steal the adb connection. This argument is optional.

            case 1045: {

                if (flagutils::vrrConfigEnabled()) {

                    float jankAmount = data.readFloat();

                    int32_t jankDelayMs = 0;

                    if (data.readInt32(&jankDelayMs) != NO_ERROR) {

                        jankDelayMs = 0;

                    }



                    const auto jankDelayDuration = Duration(std::chrono::milliseconds(jankDelayMs));



                    const bool jankAmountValid = jankAmount > 0.0 && jankAmount < 100.0;



                    if (!jankAmountValid) {

                        ALOGD("Ignoring invalid jank amount: %f", jankAmount);

                        reply->writeInt32(BAD_VALUE);

                        return BAD_VALUE;

                    }



                    (void)mScheduler->scheduleDelayed(

                            [&, jankAmount]() FTL_FAKE_GUARD(kMainThreadContext) {

                                mScheduler->injectPacesetterDelay(jankAmount);

                                scheduleComposite(FrameHint::kActive);

                            },

                            jankDelayDuration.ns());

                    reply->writeInt32(NO_ERROR);

                    return NO_ERROR;

                }

                return err;

            }

        }

    }

    return err;