commit b1b9d41c73cfb388a81a2bc45b0c6708e2e627f7
author Ady Abraham <adyabr@google.com> Mon Jun 01 19:53:52 2020 -0700
committer Ady Abraham <adyabr@google.com> Tue Jun 09 16:59:33 2020 -0700
tree fb39bff05fb24b784939352229330b6eea078d86
parent 607a0c6d5a2bb18fdf11374a40f5ffedca96d650

SurfaceFlinger: define a known frame rates list

Keep a list of known frame rates that would be used when we calculated
heuristically the frame rate of a layer. This keeps the signal to the
algorithm that chooses the refresh rate steady and avoid strange
frame rates like 57.2 due to inconsistent presentation timestamps.

Bug: 157540021
Test: adb shell /data/nativetest64/libsurfaceflinger_unittest/libsurfaceflinger_unittest
Change-Id: I97a24b74605256646e9b8444bd9f3818fe0a4a2a

services/surfaceflinger/Scheduler/RefreshRateConfigs.h

diff --git a/services/surfaceflinger/Scheduler/RefreshRateConfigs.h b/services/surfaceflinger/Scheduler/RefreshRateConfigs.h
index ff1eabd..88e4eb5 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateConfigs.h
+++ b/services/surfaceflinger/Scheduler/RefreshRateConfigs.h
@@ -29,7 +29,6 @@
 #include "Scheduler/StrongTyping.h"
 
 namespace android::scheduler {
-class RefreshRateConfigsTest;
 
 using namespace std::chrono_literals;
 
@@ -87,7 +86,7 @@
 
     private:
         friend RefreshRateConfigs;
-        friend RefreshRateConfigsTest;
+        friend class RefreshRateConfigsTest;
 
         // The tolerance within which we consider FPS approximately equals.
         static constexpr float FPS_EPSILON = 0.001f;
@@ -258,11 +257,18 @@
     // Returns a string that represents the layer vote type
     static std::string layerVoteTypeString(LayerVoteType vote);
 
+    // Returns a known frame rate that is the closest to frameRate
+    float findClosestKnownFrameRate(float frameRate) const;
+
     RefreshRateConfigs(const std::vector<std::shared_ptr<const HWC2::Display::Config>>& configs,
                        HwcConfigIndexType currentConfigId);
 
 private:
+    friend class RefreshRateConfigsTest;
+
     void constructAvailableRefreshRates() REQUIRES(mLock);
+    static std::vector<float> constructKnownFrameRates(
+            const std::vector<std::shared_ptr<const HWC2::Display::Config>>& configs);
 
     void getSortedRefreshRateList(
             const std::function<bool(const RefreshRate&)>& shouldAddRefreshRate,
@@ -320,6 +326,10 @@
     const RefreshRate* mMaxSupportedRefreshRate;
 
     mutable std::mutex mLock;
+
+    // A sorted list of known frame rates that a Heuristic layer will choose
+    // from based on the closest value.
+    const std::vector<float> mKnownFrameRates;
 };
 
 } // namespace android::scheduler