SF: Add FenceTracker

FenceTracker tracks all fences in SurfaceFlinger. These timestamps
could be used for debugging, profiling, or be exposed to the
application.

Change-Id: I4297a661c0a7530e744168ac7a2a66c4bca92fd5
diff --git a/services/surfaceflinger/FenceTracker.h b/services/surfaceflinger/FenceTracker.h
new file mode 100644
index 0000000..de99820
--- /dev/null
+++ b/services/surfaceflinger/FenceTracker.h
@@ -0,0 +1,103 @@
+/*
+ * Copyright 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_FENCETRACKER_H
+#define ANDROID_FENCETRACKER_H
+
+#include <ui/Fence.h>
+#include <utils/Mutex.h>
+#include <utils/RefBase.h>
+#include <utils/String8.h>
+#include <utils/Timers.h>
+#include <utils/Vector.h>
+
+#include <unordered_map>
+
+namespace android {
+
+class Layer;
+
+/*
+ * Keeps a circular buffer of fence/timestamp data for the last N frames in
+ * SurfaceFlinger. Gets timestamps for fences after they have signaled.
+ */
+class FenceTracker {
+public:
+     FenceTracker();
+     void dump(String8* outString);
+     void addFrame(nsecs_t refreshStartTime, sp<Fence> retireFence,
+             const Vector<sp<Layer>>& layers, sp<Fence> glDoneFence);
+
+protected:
+     static constexpr size_t MAX_FRAME_HISTORY = 128;
+
+     struct LayerRecord {
+         String8 name; // layer name
+         uint64_t frameNumber; // frame number for this layer
+         bool isGlesComposition; // was GLES composition used for this layer?
+         nsecs_t postedTime; // time when buffer was queued
+         nsecs_t acquireTime; // timestamp from the acquire fence
+         nsecs_t releaseTime; // timestamp from the release fence
+         sp<Fence> acquireFence; // acquire fence
+         sp<Fence> releaseFence; // release fence
+
+         LayerRecord(const String8& name, uint64_t frameNumber,
+                 bool isGlesComposition, nsecs_t postedTime,
+                 nsecs_t acquireTime, nsecs_t releaseTime,
+                 sp<Fence> acquireFence, sp<Fence> releaseFence) :
+                 name(name), frameNumber(frameNumber),
+                 isGlesComposition(isGlesComposition), postedTime(postedTime),
+                 acquireTime(acquireTime), releaseTime(releaseTime),
+                 acquireFence(acquireFence), releaseFence(releaseFence) {};
+         LayerRecord() : name("uninitialized"), frameNumber(0),
+                 isGlesComposition(false), postedTime(0), acquireTime(0),
+                 releaseTime(0), acquireFence(Fence::NO_FENCE),
+                 releaseFence(Fence::NO_FENCE) {};
+     };
+
+     struct FrameRecord {
+         // global SurfaceFlinger frame counter
+         uint64_t frameId;
+         // layer data for this frame
+         std::unordered_map<int32_t, LayerRecord> layers;
+         // timestamp for when SurfaceFlinger::handleMessageRefresh() was called
+         nsecs_t refreshStartTime;
+         // timestamp from the retire fence
+         nsecs_t retireTime;
+         // timestamp from the GLES composition completion fence
+         nsecs_t glesCompositionDoneTime;
+         // primary display retire fence for this frame
+         sp<Fence> retireFence;
+         // if GLES composition was done, the fence for its completion
+         sp<Fence> glesCompositionDoneFence;
+
+         FrameRecord() : frameId(0), layers(), refreshStartTime(0),
+                 retireTime(0), glesCompositionDoneTime(0),
+                 retireFence(Fence::NO_FENCE),
+                 glesCompositionDoneFence(Fence::NO_FENCE) {}
+     };
+
+     uint64_t mFrameCounter;
+     uint32_t mOffset;
+     FrameRecord mFrames[MAX_FRAME_HISTORY];
+     Mutex mMutex;
+
+     void checkFencesForCompletion();
+};
+
+}
+
+#endif // ANDROID_FRAMETRACKER_H