Merge "[TimeStats] reduce aggregated stats size for shared timeline-based stats"

    ATRACE_CALL();

    std::lock_guard<std::mutex> lock(mMutex);

    // Only update layer stats if we're allowed to do so.

    // Only update layer stats if we're already tracking the layer in TimeStats.

    // Otherwise, continue tracking the statistic but use a default layer name instead.

    // As an implementation detail, we do this because this method is expected to be

    // called from FrameTimeline, which is allowed to do jank analysis well after a frame is

    // presented. This means that we can't rely on TimeStats to flush layer records over to the

    // aggregated stats.

    if (!canAddNewAggregatedStats(uid, layerName)) {

        return;

    }

    // Defensively initialize the stats in case FrameTimeline flushes its signaled present fences

    // before TimeStats does.

    // called from FrameTimeline, whose jank classification includes transaction jank

    // that occurs without a buffer. But, in general those layer names are not suitable as

    // aggregation keys: e.g., it's normal and expected for Window Manager to include the hash code

    // for an animation leash. So while we can show that jank in dumpsys, aggregating based on the

    // layer blows up the stats size, so as a workaround drop those stats. This assumes that

    // TimeStats will flush the first present fence for a layer *before* FrameTimeline does so that

    // the first jank record is not dropped.

    bool useDefaultLayerKey = false;

    static const std::string kDefaultLayerName = "none";

    if (!mTimeStats.stats.count({uid, layerName})) {

        mTimeStats.stats[{uid, layerName}].uid = uid;

        mTimeStats.stats[{uid, layerName}].layerName = layerName;

        mTimeStats.stats[{uid, kDefaultLayerName}].uid = uid;

        mTimeStats.stats[{uid, kDefaultLayerName}].layerName = kDefaultLayerName;

        useDefaultLayerKey = true;

    }

    TimeStatsHelper::TimeStatsLayer& timeStatsLayer = mTimeStats.stats[{uid, layerName}];

    TimeStatsHelper::TimeStatsLayer& timeStatsLayer =

            mTimeStats.stats[{uid, useDefaultLayerKey ? kDefaultLayerName : layerName}];

    updateJankPayload<TimeStatsHelper::TimeStatsLayer>(timeStatsLayer, reasons);

}