1 files changed, 117 insertions, 0 deletions
diff --git a/libs/gui/OccupancyTracker.cpp b/libs/gui/OccupancyTracker.cpp
new file mode 100644
index 0000000000..9687aaf744
--- /dev/null
+++ b/libs/gui/OccupancyTracker.cpp
@@ -0,0 +1,117 @@
+/*
+ * 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.
+ */
+
+#undef LOG_TAG
+#define LOG_TAG "OccupancyTracker"
+
+#include <gui/OccupancyTracker.h>
+#include <binder/Parcel.h>
+#include <utils/String8.h>
+#include <utils/Trace.h>
+
+#include <inttypes.h>
+
+namespace android {
+
+status_t OccupancyTracker::Segment::writeToParcel(Parcel* parcel) const {
+    status_t result = parcel->writeInt64(totalTime);
+    if (result != OK) {
+        return result;
+    }
+    result = parcel->writeUint64(static_cast<uint64_t>(numFrames));
+    if (result != OK) {
+        return result;
+    }
+    result = parcel->writeFloat(occupancyAverage);
+    if (result != OK) {
+        return result;
+    }
+    return parcel->writeBool(usedThirdBuffer);
+}
+
+status_t OccupancyTracker::Segment::readFromParcel(const Parcel* parcel) {
+    status_t result = parcel->readInt64(&totalTime);
+    if (result != OK) {
+        return result;
+    }
+    uint64_t uintNumFrames = 0;
+    result = parcel->readUint64(&uintNumFrames);
+    if (result != OK) {
+        return result;
+    }
+    numFrames = static_cast<size_t>(uintNumFrames);
+    result = parcel->readFloat(&occupancyAverage);
+    if (result != OK) {
+        return result;
+    }
+    return parcel->readBool(&usedThirdBuffer);
+}
+
+void OccupancyTracker::registerOccupancyChange(size_t occupancy) {
+    ATRACE_CALL();
+    nsecs_t now = systemTime();
+    nsecs_t delta = now - mLastOccupancyChangeTime;
+    if (delta > NEW_SEGMENT_DELAY) {
+        recordPendingSegment();
+    } else {
+        mPendingSegment.totalTime += delta;
+        if (mPendingSegment.mOccupancyTimes.count(mLastOccupancy)) {
+            mPendingSegment.mOccupancyTimes[mLastOccupancy] += delta;
+        } else {
+            mPendingSegment.mOccupancyTimes[mLastOccupancy] = delta;
+        }
+    }
+    if (occupancy > mLastOccupancy) {
+        ++mPendingSegment.numFrames;
+    }
+    mLastOccupancyChangeTime = now;
+    mLastOccupancy = occupancy;
+}
+
+std::vector<OccupancyTracker::Segment> OccupancyTracker::getSegmentHistory(
+        bool forceFlush) {
+    if (forceFlush) {
+        recordPendingSegment();
+    }
+    std::vector<Segment> segments(mSegmentHistory.cbegin(),
+            mSegmentHistory.cend());
+    mSegmentHistory.clear();
+    return segments;
+}
+
+void OccupancyTracker::recordPendingSegment() {
+    // Only record longer segments to get a better measurement of actual double-
+    // vs. triple-buffered time
+    if (mPendingSegment.numFrames > LONG_SEGMENT_THRESHOLD) {
+        float occupancyAverage = 0.0f;
+        bool usedThirdBuffer = false;
+        for (const auto& timePair : mPendingSegment.mOccupancyTimes) {
+            size_t occupancy = timePair.first;
+            float timeRatio = static_cast<float>(timePair.second) /
+                    mPendingSegment.totalTime;
+            occupancyAverage += timeRatio * occupancy;
+            usedThirdBuffer = usedThirdBuffer || (occupancy > 1);
+        }
+        mSegmentHistory.push_front({mPendingSegment.totalTime,
+                mPendingSegment.numFrames, occupancyAverage, usedThirdBuffer});
+        if (mSegmentHistory.size() > MAX_HISTORY_SIZE) {
+            mSegmentHistory.pop_back();
+        }
+    }
+    mPendingSegment.clear();
+}
+
+} // namespace android