SF: wait instead of presenting early
If SurfaceFlinger duration is configured to a larger value
than the vsync period, there might be a chance that SF would
present the frame too early, if its actual duration is much shorter
than anticipating. To prevent this, we wait until the vsync occurs
before calling to hwc::present.
Bug: 185949581
Test: Configure large SF duration and observe systrace
Change-Id: Ic0c112a2808036d0f2e14a345c401fa56c2d29ab
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/CompositionRefreshArgs.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/CompositionRefreshArgs.h
index a0606b4..289cb11 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/CompositionRefreshArgs.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/CompositionRefreshArgs.h
@@ -79,6 +79,9 @@
// If set, causes the dirty regions to flash with the delay
std::optional<std::chrono::microseconds> devOptFlashDirtyRegionsDelay;
+
+ // The earliest time to send the present command to the HAL
+ std::chrono::steady_clock::time_point earliestPresentTime;
};
} // namespace android::compositionengine
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h
index 8f767d3..f0ef6d6 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h
@@ -115,6 +115,9 @@
// Current target dataspace
ui::Dataspace targetDataspace{ui::Dataspace::UNKNOWN};
+ // The earliest time to send the present command to the HAL
+ std::chrono::steady_clock::time_point earliestPresentTime;
+
// Debugging
void dump(std::string& result) const;
};
diff --git a/services/surfaceflinger/CompositionEngine/src/Display.cpp b/services/surfaceflinger/CompositionEngine/src/Display.cpp
index a605fe1..1ffb1c8 100644
--- a/services/surfaceflinger/CompositionEngine/src/Display.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Display.cpp
@@ -367,6 +367,11 @@
return fences;
}
+ {
+ ATRACE_NAME("wait for earliest present time");
+ std::this_thread::sleep_until(getState().earliestPresentTime);
+ }
+
auto& hwc = getCompositionEngine().getHwComposer();
hwc.presentAndGetReleaseFences(*halDisplayIdOpt);
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index 3468b20..faa4b74 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -711,6 +711,8 @@
return;
}
+ editState().earliestPresentTime = refreshArgs.earliestPresentTime;
+
sp<GraphicBuffer> previousOverride = nullptr;
for (auto* layer : getOutputLayersOrderedByZ()) {
bool skipLayer = false;
diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 1d25c72..57bd045 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -927,4 +927,11 @@
}
}
+std::chrono::steady_clock::time_point Scheduler::getPreviousVsyncFrom(
+ nsecs_t expectedPresentTime) const {
+ const auto presentTime = std::chrono::nanoseconds(expectedPresentTime);
+ const auto vsyncPeriod = std::chrono::nanoseconds(mVsyncSchedule.tracker->currentPeriod());
+ return std::chrono::steady_clock::time_point(presentTime - vsyncPeriod);
+}
+
} // namespace android
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 4d1f3c6..49d3d93 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -149,6 +149,8 @@
bool isVsyncValid(nsecs_t expectedVsyncTimestamp, uid_t uid) const
EXCLUDES(mFrameRateOverridesMutex);
+ std::chrono::steady_clock::time_point getPreviousVsyncFrom(nsecs_t expectedPresentTime) const;
+
void dump(std::string&) const;
void dump(ConnectionHandle, std::string&) const;
void dumpVsync(std::string&) const;
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 7076124..1e3402a 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1972,6 +1972,8 @@
std::chrono::milliseconds(mDebugRegion > 1 ? mDebugRegion : 0);
}
+ refreshArgs.earliestPresentTime = mScheduler->getPreviousVsyncFrom(mExpectedPresentTime);
+
mGeometryInvalid = false;
// Store the present time just before calling to the composition engine so we could notify