SF: rate-limit luma sampling
Instead of sampling the luma regions every frame, introduce a rate
limiting system to reduce load. Introduces a few tunables to control
the rate, which is defaulted to 10Hz, when there is content being
watched for luma.
Test: manual systrace inspection, using SamplingDemo
Test: libgui_test --gtest_filter="RegionSampling*"
Test: atest CompositionSamplingListenerTest
Fixes: 126747045
Change-Id: I7cae3e90fb405ba72dc2f276a88be48f1533a219
diff --git a/services/surfaceflinger/RegionSamplingThread.h b/services/surfaceflinger/RegionSamplingThread.h
index ab06513..d4e57bf 100644
--- a/services/surfaceflinger/RegionSamplingThread.h
+++ b/services/surfaceflinger/RegionSamplingThread.h
@@ -16,6 +16,7 @@
#pragma once
+#include <chrono>
#include <condition_variable>
#include <mutex>
#include <thread>
@@ -25,17 +26,42 @@
#include <binder/IBinder.h>
#include <ui/Rect.h>
#include <utils/StrongPointer.h>
+#include "Scheduler/IdleTimer.h"
namespace android {
class GraphicBuffer;
class IRegionSamplingListener;
class Layer;
+class Scheduler;
class SurfaceFlinger;
+struct SamplingOffsetCallback;
class RegionSamplingThread : public IBinder::DeathRecipient {
public:
- explicit RegionSamplingThread(SurfaceFlinger& flinger);
+ struct TimingTunables {
+ // debug.sf.sampling_offset_ns
+ // When asynchronously collecting sample, the offset, from zero phase in the vsync timeline
+ // at which the sampling should start.
+ std::chrono::nanoseconds mSamplingOffset;
+ // debug.sf.sampling_period_ns
+ // This is the maximum amount of time the luma recieving client
+ // should have to wait for a new luma value after a frame is updated. The inverse of this is
+ // roughly the sampling rate. Sampling system rounds up sub-vsync sampling period to vsync
+ // period.
+ std::chrono::nanoseconds mSamplingPeriod;
+ // debug.sf.sampling_timer_timeout_ns
+ // This is the interval at which the luma sampling system will check that the luma clients
+ // have up to date information. It defaults to the mSamplingPeriod.
+ std::chrono::nanoseconds mSamplingTimerTimeout;
+ };
+ struct EnvironmentTimingTunables : TimingTunables {
+ EnvironmentTimingTunables();
+ };
+ explicit RegionSamplingThread(SurfaceFlinger& flinger, Scheduler& scheduler,
+ const TimingTunables& tunables);
+ explicit RegionSamplingThread(SurfaceFlinger& flinger, Scheduler& scheduler);
+
~RegionSamplingThread();
// Add a listener to receive luma notifications. The luma reported via listener will
@@ -44,8 +70,13 @@
const sp<IRegionSamplingListener>& listener);
// Remove the listener to stop receiving median luma notifications.
void removeListener(const sp<IRegionSamplingListener>& listener);
- // Instruct the thread to perform a median luma sampling on the layers.
- void sampleNow();
+
+ // Notifies sampling engine that new content is available. This will trigger a sampling
+ // pass at some point in the future.
+ void notifyNewContent();
+
+ // Notifies the sampling engine that it has a good timing window in which to sample.
+ void notifySamplingOffset();
private:
struct Descriptor {
@@ -63,12 +94,19 @@
const sp<GraphicBuffer>& buffer, const Point& leftTop,
const std::vector<RegionSamplingThread::Descriptor>& descriptors);
+ void doSample();
void binderDied(const wp<IBinder>& who) override;
+ void checkForStaleLuma();
void captureSample() REQUIRES(mMutex);
void threadMain();
SurfaceFlinger& mFlinger;
+ Scheduler& mScheduler;
+ const TimingTunables mTunables;
+ scheduler::IdleTimer mIdleTimer;
+
+ std::unique_ptr<SamplingOffsetCallback> const mPhaseCallback;
std::mutex mThreadMutex;
std::thread mThread GUARDED_BY(mThreadMutex);
@@ -79,6 +117,8 @@
bool mSampleRequested GUARDED_BY(mMutex) = false;
std::unordered_map<wp<IBinder>, Descriptor, WpHash> mDescriptors GUARDED_BY(mMutex);
+ std::chrono::nanoseconds lastSampleTime GUARDED_BY(mMutex);
+ bool mDiscardedFrames GUARDED_BY(mMutex) = false;
};
} // namespace android