commit c94ca83964accc75b08060a265abe2a346de1c2d
author Kevin DuBois <kevindubois@google.com> Tue Nov 26 12:56:24 2019 -0800
committer Kevin DuBois <kevindubois@google.com> Thu Dec 19 09:08:07 2019 -0800
tree 2beb0bcb75490a4b0ee392a770f76f509f30ef41
parent f91e9236bc80482b1c327f8fb7306c5b0b419e65

SF: VSyncDispatch: correct vsync prediction drift

Refine VSyncDispatch::schedule implementation so that refining
the prediction by small amounts would not lead to skipped callbacks.
The current implementation did not account for a case where
a valid vsync callback would be skipped. (exposed
in unit testing). Like the rest of VSyncDispatch, this
code is flagged off (ie, latent, not production code yet)

Fixes: 145213786
Bug: 146050690
Test: 6 new unit tests, 3 unit test change
Test: validation via systrace

Change-Id: I400fc5e3c181b49ab237b0dd0da2a62e38522fa0

services/surfaceflinger/tests/unittests/VSyncDispatchRealtimeTest.cpp

diff --git a/services/surfaceflinger/tests/unittests/VSyncDispatchRealtimeTest.cpp b/services/surfaceflinger/tests/unittests/VSyncDispatchRealtimeTest.cpp
index 484947d..5846c77 100644
--- a/services/surfaceflinger/tests/unittests/VSyncDispatchRealtimeTest.cpp
+++ b/services/surfaceflinger/tests/unittests/VSyncDispatchRealtimeTest.cpp
@@ -92,6 +92,7 @@
 
 struct VSyncDispatchRealtimeTest : testing::Test {
     static nsecs_t constexpr mDispatchGroupThreshold = toNs(100us);
+    static nsecs_t constexpr mVsyncMoveThreshold = toNs(500us);
     static size_t constexpr mIterations = 20;
 };
 
@@ -148,7 +149,8 @@
 
 TEST_F(VSyncDispatchRealtimeTest, triple_alarm) {
     FixedRateIdealStubTracker tracker;
-    VSyncDispatchTimerQueue dispatch(std::make_unique<Timer>(), tracker, mDispatchGroupThreshold);
+    VSyncDispatchTimerQueue dispatch(std::make_unique<Timer>(), tracker, mDispatchGroupThreshold,
+                                     mVsyncMoveThreshold);
 
     static size_t constexpr num_clients = 3;
     std::array<RepeatingCallbackReceiver, num_clients>
@@ -176,7 +178,8 @@
 TEST_F(VSyncDispatchRealtimeTest, vascillating_vrr) {
     auto next_vsync_interval = toNs(3ms);
     VRRStubTracker tracker(next_vsync_interval);
-    VSyncDispatchTimerQueue dispatch(std::make_unique<Timer>(), tracker, mDispatchGroupThreshold);
+    VSyncDispatchTimerQueue dispatch(std::make_unique<Timer>(), tracker, mDispatchGroupThreshold,
+                                     mVsyncMoveThreshold);
 
     RepeatingCallbackReceiver cb_receiver(dispatch, toNs(1ms));
 
@@ -193,7 +196,8 @@
 // starts at 333hz, jumps to 200hz at frame 10
 TEST_F(VSyncDispatchRealtimeTest, fixed_jump) {
     VRRStubTracker tracker(toNs(3ms));
-    VSyncDispatchTimerQueue dispatch(std::make_unique<Timer>(), tracker, mDispatchGroupThreshold);
+    VSyncDispatchTimerQueue dispatch(std::make_unique<Timer>(), tracker, mDispatchGroupThreshold,
+                                     mVsyncMoveThreshold);
 
     RepeatingCallbackReceiver cb_receiver(dispatch, toNs(1ms));