commit b5daa9109e3a421d5afdbe64b384bbf501770e9c
author Tim Murray <timmurray@google.com> Wed Sep 09 21:29:13 2020 +0000
committer Tim Murray <timmurray@google.com> Fri Sep 25 17:16:27 2020 +0000
tree 49ae18df6990c928054f2340b1a384cc5e8f5efb
parent d7016343a92974751e498fe4ca49a07f79031741

EventThread: wake for two frames after vsync request by default

The common case seems to be that many frames are rendered in a row
before the system quiesces, but EventThread assumes that only a single
frame will be rendered after a call to requestNextVsync. This patch
moves requestNextVsync to wake for two frames by default, allowing it to
skip the EventThread wakeup when there's a pending wakeup for that
EventThread already.

Test: no EventThread wakeups from requestNextVsync in BouncyBall
bug: 169368457
Change-Id: I5cb880dad27062e158de640540a73cba59b223e5

services/surfaceflinger/Scheduler/EventThread.cpp

diff --git a/services/surfaceflinger/Scheduler/EventThread.cpp b/services/surfaceflinger/Scheduler/EventThread.cpp
index 3307388..bf2a509 100644
--- a/services/surfaceflinger/Scheduler/EventThread.cpp
+++ b/services/surfaceflinger/Scheduler/EventThread.cpp
@@ -62,6 +62,8 @@
             return "VSyncRequest::None";
         case VSyncRequest::Single:
             return "VSyncRequest::Single";
+        case VSyncRequest::SingleSuppressCallback:
+            return "VSyncRequest::SingleSuppressCallback";
         default:
             return StringPrintf("VSyncRequest::Periodic{period=%d}", vsyncPeriod(request));
     }
@@ -267,6 +269,8 @@
     if (connection->vsyncRequest == VSyncRequest::None) {
         connection->vsyncRequest = VSyncRequest::Single;
         mCondition.notify_all();
+    } else if (connection->vsyncRequest == VSyncRequest::SingleSuppressCallback) {
+        connection->vsyncRequest = VSyncRequest::Single;
     }
 }
 
@@ -451,8 +455,11 @@
             switch (connection->vsyncRequest) {
                 case VSyncRequest::None:
                     return false;
-                case VSyncRequest::Single:
+                case VSyncRequest::SingleSuppressCallback:
                     connection->vsyncRequest = VSyncRequest::None;
+                    return false;
+                case VSyncRequest::Single:
+                    connection->vsyncRequest = VSyncRequest::SingleSuppressCallback;
                     return true;
                 case VSyncRequest::Periodic:
                     return true;