EGL: add GPU frame completion tracing

This change adds a debug option to EGL to use an EGLSyncKHR each frame to
determine when the GPU finishes rendering the frame.

Change-Id: I09ce071db904b44f07ca814c586c291c8b59385a

3 files changed, 84 insertions, 3 deletions

diff --git a/opengl/libs/EGL/eglApi.cpp b/opengl/libs/EGL/eglApi.cpp
index 8bfa16d..8df7d39 100644
--- a/opengl/libs/EGL/eglApi.cpp
+++ b/opengl/libs/EGL/eglApi.cpp
@@ -715,6 +715,69 @@ __eglMustCastToProperFunctionPointerType eglGetProcAddress(const char *procname)
     return addr;
 }
 
+class FrameCompletionThread : public Thread {
+public:
+
+    static void queueSync(EGLSyncKHR sync) {
+        static sp<FrameCompletionThread> thread(new FrameCompletionThread);
+        static bool running = false;
+        if (!running) {
+            thread->run("GPUFrameCompletion");
+            running = true;
+        }
+        {
+            Mutex::Autolock lock(thread->mMutex);
+            ScopedTrace st(ATRACE_TAG, String8::format("kicked off frame %d",
+                    thread->mFramesQueued).string());
+            thread->mQueue.push_back(sync);
+            thread->mCondition.signal();
+            thread->mFramesQueued++;
+            ATRACE_INT("GPU Frames Outstanding", thread->mQueue.size());
+        }
+    }
+
+private:
+    FrameCompletionThread() : mFramesQueued(0), mFramesCompleted(0) {}
+
+    virtual bool threadLoop() {
+        EGLSyncKHR sync;
+        uint32_t frameNum;
+        {
+            Mutex::Autolock lock(mMutex);
+            while (mQueue.isEmpty()) {
+                mCondition.wait(mMutex);
+            }
+            sync = mQueue[0];
+            frameNum = mFramesCompleted;
+        }
+        EGLDisplay dpy = eglGetDisplay(EGL_DEFAULT_DISPLAY);
+        {
+            ScopedTrace st(ATRACE_TAG, String8::format("waiting for frame %d",
+                    frameNum).string());
+            EGLint result = eglClientWaitSyncKHR(dpy, sync, 0, EGL_FOREVER_KHR);
+            if (result == EGL_FALSE) {
+                ALOGE("FrameCompletion: error waiting for fence: %#x", eglGetError());
+            } else if (result == EGL_TIMEOUT_EXPIRED_KHR) {
+                ALOGE("FrameCompletion: timeout waiting for fence");
+            }
+            eglDestroySyncKHR(dpy, sync);
+        }
+        {
+            Mutex::Autolock lock(mMutex);
+            mQueue.removeAt(0);
+            mFramesCompleted++;
+            ATRACE_INT("GPU Frames Outstanding", mQueue.size());
+        }
+        return true;
+    }
+
+    uint32_t mFramesQueued;
+    uint32_t mFramesCompleted;
+    Vector<EGLSyncKHR> mQueue;
+    Condition mCondition;
+    Mutex mMutex;
+};
+
 EGLBoolean eglSwapBuffers(EGLDisplay dpy, EGLSurface draw)
 {
     ATRACE_CALL();
@@ -744,7 +807,19 @@ EGLBoolean eglSwapBuffers(EGLDisplay dpy, EGLSurface draw)
         }
     }
 
-    return s->cnx->egl.eglSwapBuffers(dp->disp.dpy, s->surface);
+    EGLBoolean result = s->cnx->egl.eglSwapBuffers(dp->disp.dpy, s->surface);
+
+    if (CC_UNLIKELY(dp->traceGpuCompletion)) {
+        EGLSyncKHR sync = EGL_NO_SYNC_KHR;
+        {
+            sync = eglCreateSyncKHR(dpy, EGL_SYNC_FENCE_KHR, NULL);
+        }
+        if (sync != EGL_NO_SYNC_KHR) {
+            FrameCompletionThread::queueSync(sync);
+        }
+    }
+
+    return result;
 }
 
 EGLBoolean eglCopyBuffers(  EGLDisplay dpy, EGLSurface surface,
diff --git a/opengl/libs/EGL/egl_display.cpp b/opengl/libs/EGL/egl_display.cpp
index b80afd6..6b6f8cf 100644
--- a/opengl/libs/EGL/egl_display.cpp
+++ b/opengl/libs/EGL/egl_display.cpp
@@ -67,7 +67,7 @@ extern void setGLHooksThreadSpecific(gl_hooks_t const *value);
 egl_display_t egl_display_t::sDisplay[NUM_DISPLAYS];
 
 egl_display_t::egl_display_t() :
-    magic('_dpy'), finishOnSwap(false), refs(0) {
+    magic('_dpy'), finishOnSwap(false), traceGpuCompletion(false), refs(0) {
 }
 
 egl_display_t::~egl_display_t() {
@@ -239,6 +239,11 @@ EGLBoolean egl_display_t::initialize(EGLint *major, EGLint *minor) {
         finishOnSwap = true;
     }
 
+    property_get("debug.egl.traceGpuCompletion", value, "0");
+    if (atoi(value)) {
+        traceGpuCompletion = true;
+    }
+
     refs++;
     if (major != NULL)
         *major = VERSION_MAJOR;
diff --git a/opengl/libs/EGL/egl_display.h b/opengl/libs/EGL/egl_display.h
index 43738ea..3e22efa 100644
--- a/opengl/libs/EGL/egl_display.h
+++ b/opengl/libs/EGL/egl_display.h
@@ -107,7 +107,8 @@ private:
 
 public:
     DisplayImpl     disp;
-    bool    finishOnSwap;
+    bool    finishOnSwap;       // property: debug.egl.finish
+    bool    traceGpuCompletion; // property: debug.egl.traceGpuCompletion
 
 private:
             uint32_t                    refs;