commit 1aa9e023dd483698f35c06dc9caaefe53e005be4
author Ady Abraham <adyabr@google.com> Thu Sep 19 22:02:34 2019 -0700
committer android-build-merger <android-build-merger@google.com> Thu Sep 19 22:02:34 2019 -0700
tree 39f58b8831f5e3bcb5db253cad3fbe1cbfde74a7
parent f1c22a3a6348d800884f7f7b45bb21da480ab33f
parent 8f8c3ef0ef4112f1f5957ae9204936d8a2167f2c

Merge "SurfaceFlinger: add grace time for present fence to signal" into qt-qpr1-dev
am: 8f8c3ef0ef

Change-Id: I85b033c02d092fafc5c9b99f9d18eee79f7ca6dc

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 3a96f73..f91a9c3 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1681,7 +1681,8 @@
     setTransactionFlags(eDisplayTransactionNeeded);
 }
 
-bool SurfaceFlinger::previousFrameMissed() NO_THREAD_SAFETY_ANALYSIS {
+bool SurfaceFlinger::previousFrameMissed(int graceTimeMs) NO_THREAD_SAFETY_ANALYSIS {
+    ATRACE_CALL();
     // We are storing the last 2 present fences. If sf's phase offset is to be
     // woken up before the actual vsync but targeting the next vsync, we need to check
     // fence N-2
@@ -1690,7 +1691,15 @@
             ? mPreviousPresentFences[0]
             : mPreviousPresentFences[1];
 
-    return fence != Fence::NO_FENCE && (fence->getStatus() == Fence::Status::Unsignaled);
+    if (fence == Fence::NO_FENCE) {
+        return false;
+    }
+
+    if (graceTimeMs > 0 && fence->getStatus() == Fence::Status::Unsignaled) {
+        fence->wait(graceTimeMs);
+    }
+
+    return (fence->getStatus() == Fence::Status::Unsignaled);
 }
 
 void SurfaceFlinger::populateExpectedPresentTime() NO_THREAD_SAFETY_ANALYSIS {
@@ -1713,7 +1722,15 @@
             // seeing this same value.
             populateExpectedPresentTime();
 
-            bool frameMissed = previousFrameMissed();
+            // When Backpressure propagation is enabled we want to give a small grace period
+            // for the present fence to fire instead of just giving up on this frame to handle cases
+            // where present fence is just about to get signaled.
+            const int graceTimeForPresentFenceMs =
+                    (mPropagateBackpressure &&
+                     (mPropagateBackpressureClientComposition || !mHadClientComposition))
+                    ? 1
+                    : 0;
+            bool frameMissed = previousFrameMissed(graceTimeForPresentFenceMs);
             bool hwcFrameMissed = mHadDeviceComposition && frameMissed;
             bool gpuFrameMissed = mHadClientComposition && frameMissed;
             ATRACE_INT("FrameMissed", static_cast<int>(frameMissed));

services/surfaceflinger/SurfaceFlinger.h

diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index f034832..333b4b9 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -848,7 +848,7 @@
         return hwcDisplayId ? getHwComposer().toPhysicalDisplayId(*hwcDisplayId) : std::nullopt;
     }
 
-    bool previousFrameMissed();
+    bool previousFrameMissed(int graceTimeMs = 0);
     void setVsyncEnabledInHWC(DisplayId displayId, HWC2::Vsync enabled);
 
     /*