commit b818bfaf7b5bb2f62ed8af0a3ede300a8eb65e2f
author Kevin DuBois <kevindubois@google.com> Fri Jul 10 14:29:36 2020 -0700
committer Kevin DuBois <kevindubois@google.com> Mon Jul 13 18:33:09 2020 +0000
tree 66e35869221fee7d2ba1a45243051ddb64f5870e
parent 7a1a78e7b549c6c745f130aa1630929a33db441a

SF: hwvsync on for more samples on recalibration

Decrease the amount of time that the VSyncPredictor is using the
idealPeriod (ie, the hwc-reported period) by leaving hwVsync on until
there's enough info (4 additional pulses) to infer device's
measured/actual period.

This will benefit frames that come intermittently, as the vsync's
cumulative error over the larger time gap will be smaller, giving the
timer a better chance of landing closer to the vsync signal when those
one-off frames come in.

Test: 3 new unit tests, 2 other tests modified in substance.
Test: dogfooding
Test: uibench
Fixes: 159896971

Change-Id: Ic3190822e38c5a24d3445ea89ef6d7e34a590077

services/surfaceflinger/Scheduler/VSyncReactor.cpp

diff --git a/services/surfaceflinger/Scheduler/VSyncReactor.cpp b/services/surfaceflinger/Scheduler/VSyncReactor.cpp
index c743de0..efa8bab 100644
--- a/services/surfaceflinger/Scheduler/VSyncReactor.cpp
+++ b/services/surfaceflinger/Scheduler/VSyncReactor.cpp
@@ -233,6 +233,7 @@
 }
 
 void VSyncReactor::startPeriodTransition(nsecs_t newPeriod) {
+    ATRACE_CALL();
     mPeriodConfirmationInProgress = true;
     mPeriodTransitioningTo = newPeriod;
     mMoreSamplesNeeded = true;
@@ -240,8 +241,7 @@
 }
 
 void VSyncReactor::endPeriodTransition() {
-    setIgnorePresentFencesInternal(false);
-    mMoreSamplesNeeded = false;
+    ATRACE_CALL();
     mPeriodTransitioningTo.reset();
     mPeriodConfirmationInProgress = false;
     mLastHwVsync.reset();
@@ -254,6 +254,8 @@
 
     if (!mSupportKernelIdleTimer && period == getPeriod()) {
         endPeriodTransition();
+        setIgnorePresentFencesInternal(false);
+        mMoreSamplesNeeded = false;
     } else {
         startPeriodTransition(period);
     }
@@ -303,6 +305,7 @@
 
     std::lock_guard<std::mutex> lk(mMutex);
     if (periodConfirmed(timestamp, hwcVsyncPeriod)) {
+        ATRACE_NAME("VSR: period confirmed");
         if (mPeriodTransitioningTo) {
             mTracker->setPeriod(*mPeriodTransitioningTo);
             for (auto& entry : mCallbacks) {
@@ -310,17 +313,29 @@
             }
             *periodFlushed = true;
         }
+
+        if (mLastHwVsync) {
+            mTracker->addVsyncTimestamp(*mLastHwVsync);
+        }
+        mTracker->addVsyncTimestamp(timestamp);
+
         endPeriodTransition();
+        mMoreSamplesNeeded = mTracker->needsMoreSamples();
     } else if (mPeriodConfirmationInProgress) {
+        ATRACE_NAME("VSR: still confirming period");
         mLastHwVsync = timestamp;
         mMoreSamplesNeeded = true;
         *periodFlushed = false;
     } else {
-        mMoreSamplesNeeded = false;
+        ATRACE_NAME("VSR: adding sample");
         *periodFlushed = false;
+        mTracker->addVsyncTimestamp(timestamp);
+        mMoreSamplesNeeded = mTracker->needsMoreSamples();
     }
 
-    mTracker->addVsyncTimestamp(timestamp);
+    if (!mMoreSamplesNeeded) {
+        setIgnorePresentFencesInternal(false);
+    }
     return mMoreSamplesNeeded;
 }