Merge "[SurfaceFlinger] Exclude first vsync duration from period calculation" into qt-r1-dev
diff --git a/services/surfaceflinger/Scheduler/DispSync.cpp b/services/surfaceflinger/Scheduler/DispSync.cpp
index 83fd42b..0c94052 100644
--- a/services/surfaceflinger/Scheduler/DispSync.cpp
+++ b/services/surfaceflinger/Scheduler/DispSync.cpp
@@ -668,7 +668,13 @@
nsecs_t durationSum = 0;
nsecs_t minDuration = INT64_MAX;
nsecs_t maxDuration = 0;
- for (size_t i = 1; i < mNumResyncSamples; i++) {
+ // We skip the first 2 samples because the first vsync duration on some
+ // devices may be much more inaccurate than on other devices, e.g. due
+ // to delays in ramping up from a power collapse. By doing so this
+ // actually increases the accuracy of the DispSync model even though
+ // we're effectively relying on fewer sample points.
+ static constexpr size_t numSamplesSkipped = 2;
+ for (size_t i = numSamplesSkipped; i < mNumResyncSamples; i++) {
size_t idx = (mFirstResyncSample + i) % MAX_RESYNC_SAMPLES;
size_t prev = (idx + MAX_RESYNC_SAMPLES - 1) % MAX_RESYNC_SAMPLES;
nsecs_t duration = mResyncSamples[idx] - mResyncSamples[prev];
@@ -679,15 +685,14 @@
// Exclude the min and max from the average
durationSum -= minDuration + maxDuration;
- mPeriod = durationSum / (mNumResyncSamples - 3);
+ mPeriod = durationSum / (mNumResyncSamples - numSamplesSkipped - 2);
ALOGV("[%s] mPeriod = %" PRId64, mName, ns2us(mPeriod));
double sampleAvgX = 0;
double sampleAvgY = 0;
double scale = 2.0 * M_PI / double(mPeriod);
- // Intentionally skip the first sample
- for (size_t i = 1; i < mNumResyncSamples; i++) {
+ for (size_t i = numSamplesSkipped; i < mNumResyncSamples; i++) {
size_t idx = (mFirstResyncSample + i) % MAX_RESYNC_SAMPLES;
nsecs_t sample = mResyncSamples[idx] - mReferenceTime;
double samplePhase = double(sample % mPeriod) * scale;
@@ -695,8 +700,8 @@
sampleAvgY += sin(samplePhase);
}
- sampleAvgX /= double(mNumResyncSamples - 1);
- sampleAvgY /= double(mNumResyncSamples - 1);
+ sampleAvgX /= double(mNumResyncSamples - numSamplesSkipped);
+ sampleAvgY /= double(mNumResyncSamples - numSamplesSkipped);
mPhase = nsecs_t(atan2(sampleAvgY, sampleAvgX) / scale);