From b87c4564313c180a10f96120ec53d481f354b010 Mon Sep 17 00:00:00 2001
From: Ricardo Cerqueira <cyanogenmod@cerqueira.org>
Date: Thu, 17 Jul 2014 19:36:08 +0100
Subject: [PATCH] surfaceflinger: Track the last surfaceview frame for latency
 dumps

When measuring GL latency with dumpsys, it's possible to hit a
race condition if the hardware is fast enough to complete rendering
the test cycle before the latency dump is requested, since it only
matches the latency for live layers (unless it's an animation. See
change I8bded1ea08a4cddefef0aa955401052bb9107c90)

So always save a reference to the last rendered SurfaceView frame,
and dump its values if there isn't an active one.

Change-Id: I740e9830161396ea955b5a53322bd8576b5136bc
---
 services/surfaceflinger/SurfaceFlinger.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 08769c901..165c1b784 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -124,6 +124,8 @@ const String16 sAccessSurfaceFlinger("android.permission.ACCESS_SURFACE_FLINGER"
 const String16 sReadFramebuffer("android.permission.READ_FRAME_BUFFER");
 const String16 sDump("android.permission.DUMP");
 
+static sp<Layer> lastSurfaceViewLayer;
+
 // ---------------------------------------------------------------------------
 
 SurfaceFlinger::SurfaceFlinger()
@@ -1174,6 +1176,10 @@ void SurfaceFlinger::setUpHWComposer() {
                     const sp<Layer>& layer(currentLayers[i]);
                     layer->setPerFrameData(hw, *cur);
                     setOrientationEventControl(freezeSurfacePresent,id);
+                    if(!strncmp(layer->getName(), "SurfaceView",
+                                11)) {
+                        lastSurfaceViewLayer = layer;
+                    }
                 }
             }
         }
@@ -2612,14 +2618,19 @@ void SurfaceFlinger::dumpStatsLocked(const Vector<String16>& args, size_t& index
     if (name.isEmpty()) {
         mAnimFrameTracker.dumpStats(result);
     } else {
+        bool found = false;
         const LayerVector& currentLayers = mCurrentState.layersSortedByZ;
         const size_t count = currentLayers.size();
         for (size_t i=0 ; i<count ; i++) {
             const sp<Layer>& layer(currentLayers[i]);
             if (name == layer->getName()) {
+                found = true;
                 layer->dumpFrameStats(result);
             }
         }
+        if (!found && !strncmp(name.string(), "SurfaceView", 11)) {
+            lastSurfaceViewLayer->dumpFrameStats(result);
+        }
     }
 }