SurfaceFlinger: expose vsync id extra buffers
Expose a function for clients to call and query the number
of extra buffers needed when vsync id is passed with the buffer.
Test: launch an app and observe systrace
Test: SF unit tests
Bug: 178148035
Change-Id: Icbeec66073feeae9768f0dcc45831b26144ab6f6
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index cf7d1e1..d57d0da 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -5030,8 +5030,9 @@
case CAPTURE_DISPLAY:
case SET_DISPLAY_BRIGHTNESS:
case SET_FRAME_TIMELINE_INFO:
- // This is not sensitive information, so should not require permission control.
- case GET_GPU_CONTEXT_PRIORITY: {
+ case GET_GPU_CONTEXT_PRIORITY:
+ case GET_EXTRA_BUFFER_COUNT: {
+ // This is not sensitive information, so should not require permission control.
return OK;
}
case ADD_REGION_SAMPLING_LISTENER:
@@ -6458,6 +6459,25 @@
return getRenderEngine().getContextPriority();
}
+int SurfaceFlinger::calculateExtraBufferCount(Fps maxSupportedRefreshRate,
+ std::chrono::nanoseconds presentLatency) {
+ auto pipelineDepth = presentLatency.count() / maxSupportedRefreshRate.getPeriodNsecs();
+ if (presentLatency.count() % maxSupportedRefreshRate.getPeriodNsecs()) {
+ pipelineDepth++;
+ }
+ return std::max(0ll, pipelineDepth - 2);
+}
+
+status_t SurfaceFlinger::getExtraBufferCount(int* extraBuffers) const {
+ const auto maxSupportedRefreshRate = mRefreshRateConfigs->getSupportedRefreshRateRange().max;
+ const auto vsyncConfig =
+ mVsyncConfiguration->getConfigsForRefreshRate(maxSupportedRefreshRate).late;
+ const auto presentLatency = vsyncConfig.appWorkDuration + vsyncConfig.sfWorkDuration;
+
+ *extraBuffers = calculateExtraBufferCount(maxSupportedRefreshRate, presentLatency);
+ return NO_ERROR;
+}
+
} // namespace android
#if defined(__gl_h_)
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 400345f..49308a4 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -623,6 +623,8 @@
int getGPUContextPriority() override;
+ status_t getExtraBufferCount(int* extraBuffers) const override;
+
// Implements IBinder::DeathRecipient.
void binderDied(const wp<IBinder>& who) override;
@@ -1053,6 +1055,9 @@
return std::nullopt;
}
+ static int calculateExtraBufferCount(Fps maxSupportedRefreshRate,
+ std::chrono::nanoseconds presentLatency);
+
sp<StartPropertySetThread> mStartPropertySetThread;
surfaceflinger::Factory& mFactory;
diff --git a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
index e688e10..510b620 100644
--- a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
@@ -69,6 +69,8 @@
Scheduler::ConnectionHandle mConnectionHandle;
mock::EventThread* mEventThread;
sp<MockEventThreadConnection> mEventThreadConnection;
+
+ TestableSurfaceFlinger mFlinger;
};
SchedulerTest::SchedulerTest() {
@@ -187,4 +189,14 @@
EXPECT_CALL(*mEventThread, onConfigChanged(_, _, _)).Times(0);
}
+TEST_F(SchedulerTest, calculateExtraBufferCount) {
+ EXPECT_EQ(0, mFlinger.calculateExtraBufferCount(Fps(60), 30ms));
+ EXPECT_EQ(1, mFlinger.calculateExtraBufferCount(Fps(90), 30ms));
+ EXPECT_EQ(2, mFlinger.calculateExtraBufferCount(Fps(120), 30ms));
+
+ EXPECT_EQ(1, mFlinger.calculateExtraBufferCount(Fps(60), 40ms));
+
+ EXPECT_EQ(0, mFlinger.calculateExtraBufferCount(Fps(60), 10ms));
+}
+
} // namespace android
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 3787c43..6b145b0 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -391,6 +391,11 @@
auto getGPUContextPriority() { return mFlinger->getGPUContextPriority(); }
+ auto calculateExtraBufferCount(Fps maxSupportedRefreshRate,
+ std::chrono::nanoseconds presentLatency) const {
+ return SurfaceFlinger::calculateExtraBufferCount(maxSupportedRefreshRate, presentLatency);
+ }
+
/* ------------------------------------------------------------------------
* Read-only access to private data to assert post-conditions.
*/