commit 187d2d812711188df2fc649e276f7cb6d0fb81e4
author Ady Abraham <adyabr@google.com> Wed Jul 10 16:18:48 2019 -0700
committer Ady Abraham <adyabr@google.com> Wed Jul 10 18:25:59 2019 -0700
tree 950bab5651ca4c787d1eeb902f463c6303a65cac
parent 11b6a70c6f6780f2f878ed3e103b5ffbb0b8fc26

SurfaceFlinger: store fps instead of duration in LayerInfo

To get a better average of the content fps, we switch to store the
momentarily fps rate instead of the refresh duration.
For example:

Frame#0 at 0ms
Frame#1 at 100ms
Frame#2 at 111ms
Frame#3 at 122ms
Average based on duration is AVERAGE(100, 11, 11) = 40.6ms (25fps)
Average based on fps is AVERAGE(10, 90, 90) = 63fps

Test: app launch
Bug: 136558136
Change-Id: Icab848dd1f312498590f9735b8881ecdf0d24113

services/surfaceflinger/Scheduler/LayerInfo.h

diff --git a/services/surfaceflinger/Scheduler/LayerInfo.h b/services/surfaceflinger/Scheduler/LayerInfo.h
index 2c50053..66df9dc 100644
--- a/services/surfaceflinger/Scheduler/LayerInfo.h
+++ b/services/surfaceflinger/Scheduler/LayerInfo.h
@@ -46,7 +46,7 @@
     public:
         explicit RefreshRateHistory(nsecs_t minRefreshDuration)
               : mMinRefreshDuration(minRefreshDuration) {}
-        void insertRefreshRate(nsecs_t refreshRate) {
+        void insertRefreshRate(int refreshRate) {
             mElements.push_back(refreshRate);
             if (mElements.size() > HISTORY_SIZE) {
                 mElements.pop_front();
@@ -54,13 +54,13 @@
         }
 
         float getRefreshRateAvg() const {
-            nsecs_t refreshDuration = mMinRefreshDuration;
-            if (mElements.size() > 0) {
-                refreshDuration = scheduler::calculate_mean(mElements);
+            if (mElements.empty()) {
+                return 1e9f / mMinRefreshDuration;
             }
 
-            return 1e9f / refreshDuration;
+            return scheduler::calculate_mean(mElements);
         }
+
         void clearHistory() { mElements.clear(); }
 
     private: