commit b6c7f880460c81a6ce49ccb3334e2d2e1e020f81
author Ady Abraham <adyabr@google.com> Mon Jan 29 14:43:29 2024 -0800
committer Ady Abraham <adyabr@google.com> Tue Feb 27 16:55:32 2024 -0800
tree 6b69f86251df4b3741742b406af1fa9ba9ad483e
parent 50229b4a57e68c6630c287c8b975e0ce62c4d1d0

SF: Introduce VsyncTimeline to VsyncPredictor

Add the concept of timeline freezing when switching render rate.
This allow us to change render rates in sync with the app and remain
jank free across render rate changes.

Bug: 326599221
Test: Run TouchLatency, change render rate and examine Perfetto trace

Change-Id: Ibc8026434c0c1d50138299da3cb110b317604e92

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index cf5f55d..9e13144 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -4702,7 +4702,14 @@
         return TransactionReadiness::NotReady;
     }
 
-    if (!mScheduler->isVsyncValid(expectedPresentTime, transaction.originUid)) {
+    const auto vsyncId = VsyncId{transaction.frameTimelineInfo.vsyncId};
+
+    // Transactions with VsyncId are already throttled by the vsyncId (i.e. Choreographer issued
+    // the vsyncId according to the frame rate override cadence) so we shouldn't throttle again
+    // when applying the transaction. Otherwise we might throttle older transactions
+    // incorrectly as the frame rate of SF changed before it drained the older transactions.
+    if (ftl::to_underlying(vsyncId) == FrameTimelineInfo::INVALID_VSYNC_ID &&
+        !mScheduler->isVsyncValid(expectedPresentTime, transaction.originUid)) {
         ATRACE_FORMAT("!isVsyncValid expectedPresentTime: %" PRId64 " uid: %d", expectedPresentTime,
                       transaction.originUid);
         return TransactionReadiness::NotReady;
@@ -4710,8 +4717,7 @@
 
     // If the client didn't specify desiredPresentTime, use the vsyncId to determine the
     // expected present time of this transaction.
-    if (transaction.isAutoTimestamp &&
-        frameIsEarly(expectedPresentTime, VsyncId{transaction.frameTimelineInfo.vsyncId})) {
+    if (transaction.isAutoTimestamp && frameIsEarly(expectedPresentTime, vsyncId)) {
         ATRACE_FORMAT("frameIsEarly vsyncId: %" PRId64 " expectedPresentTime: %" PRId64,
                       transaction.frameTimelineInfo.vsyncId, expectedPresentTime);
         return TransactionReadiness::NotReady;