[SurfaceFlinger] Add deferred txn trace points.

Currently there is not enough trace information to track down jank that
is suspected to be related to deferred transactions, so adding some
trace points in this patch.

Bug: 134583193
Test: systrace
Change-Id: Iecc367dcfaa85877be0b9d9c179986bac52473f5

1 files changed, 9 insertions, 5 deletions

diff --git a/services/surfaceflinger/BufferLayer.cpp b/services/surfaceflinger/BufferLayer.cpp
index 9d723998c4..f51fbb45f6 100644
--- a/services/surfaceflinger/BufferLayer.cpp
+++ b/services/surfaceflinger/BufferLayer.cpp
@@ -19,9 +19,7 @@
 #define LOG_TAG "BufferLayer"
 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
 
-#include <cmath>
-#include <cstdlib>
-#include <mutex>
+#include "BufferLayer.h"
 
 #include <compositionengine/CompositionEngine.h>
 #include <compositionengine/Display.h>
@@ -45,11 +43,14 @@
 #include <utils/StopWatch.h>
 #include <utils/Trace.h>
 
-#include "BufferLayer.h"
+#include <cmath>
+#include <cstdlib>
+#include <mutex>
+#include <sstream>
+
 #include "Colorizer.h"
 #include "DisplayDevice.h"
 #include "LayerRejecter.h"
-
 #include "TimeStats/TimeStats.h"
 
 namespace android {
@@ -525,6 +526,9 @@ bool BufferLayer::latchBuffer(bool& recomputeVisibleRegions, nsecs_t latchTime)
             }
 
             if ((*point)->getFrameNumber() <= mCurrentFrameNumber) {
+                std::stringstream ss;
+                ss << "Dropping sync point " << (*point)->getFrameNumber();
+                ATRACE_NAME(ss.str().c_str());
                 point = mLocalSyncPoints.erase(point);
             } else {
                 ++point;