services/surfaceflinger/Scheduler/LayerHistoryV2.cpp

/*
 * Copyright 2020 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 "LayerHistoryV2"
#define ATRACE_TAG ATRACE_TAG_GRAPHICS

#include "LayerHistory.h"

#include <cutils/properties.h>
#include <utils/Log.h>
#include <utils/Timers.h>
#include <utils/Trace.h>

#include <algorithm>
#include <cmath>
#include <string>
#include <utility>

#include "../Layer.h"
#include "SchedulerUtils.h"

#include "LayerInfoV2.h"

namespace android::scheduler::impl {

namespace {

bool isLayerActive(const Layer& layer, const LayerInfoV2& info, nsecs_t threshold) {
    if (layer.getFrameRate().has_value()) {
        return layer.isVisible();
    }
    return layer.isVisible() && info.getLastUpdatedTime() >= threshold;
}

bool traceEnabled() {
    return property_get_bool("debug.sf.layer_history_trace", false);
}

bool useFrameRatePriority() {
    char value[PROPERTY_VALUE_MAX];
    property_get("debug.sf.use_frame_rate_priority", value, "1");
    return atoi(value);
}

void trace(const wp<Layer>& weak, LayerHistory::LayerVoteType type, int fps) {
    const auto layer = weak.promote();
    if (!layer) return;

    const auto& name = layer->getName();
    const auto noVoteTag = "LFPS NoVote " + name;
    const auto heuristicVoteTag = "LFPS Heuristic " + name;
    const auto explicitVoteTag = "LFPS Explicit " + name;
    const auto minVoteTag = "LFPS Min " + name;
    const auto maxVoteTag = "LFPS Max " + name;

    ATRACE_INT(noVoteTag.c_str(), type == LayerHistory::LayerVoteType::NoVote ? 1 : 0);
    ATRACE_INT(heuristicVoteTag.c_str(), type == LayerHistory::LayerVoteType::Heuristic ? fps : 0);
    ATRACE_INT(explicitVoteTag.c_str(), type == LayerHistory::LayerVoteType::Explicit ? fps : 0);
    ATRACE_INT(minVoteTag.c_str(), type == LayerHistory::LayerVoteType::Min ? 1 : 0);
    ATRACE_INT(maxVoteTag.c_str(), type == LayerHistory::LayerVoteType::Max ? 1 : 0);

    ALOGD("%s: %s @ %d Hz", __FUNCTION__, name.c_str(), fps);
}

} // namespace

LayerHistoryV2::LayerHistoryV2()
      : mTraceEnabled(traceEnabled()), mUseFrameRatePriority(useFrameRatePriority()) {}
LayerHistoryV2::~LayerHistoryV2() = default;

void LayerHistoryV2::registerLayer(Layer* layer, float /*lowRefreshRate*/, float highRefreshRate,
                                   LayerVoteType type) {
    const nsecs_t highRefreshRatePeriod = static_cast<nsecs_t>(1e9f / highRefreshRate);
    auto info = std::make_unique<LayerInfoV2>(highRefreshRatePeriod, type);
    std::lock_guard lock(mLock);
    mLayerInfos.emplace_back(layer, std::move(info));
}

void LayerHistoryV2::record(Layer* layer, nsecs_t presentTime, nsecs_t now) {
    std::lock_guard lock(mLock);

    const auto it = std::find_if(mLayerInfos.begin(), mLayerInfos.end(),
                                 [layer](const auto& pair) { return pair.first == layer; });
    LOG_FATAL_IF(it == mLayerInfos.end(), "%s: unknown layer %p", __FUNCTION__, layer);

    const auto& info = it->second;
    info->setLastPresentTime(presentTime, now);

    // Activate layer if inactive.
    if (const auto end = activeLayers().end(); it >= end) {
        std::iter_swap(it, end);
        mActiveLayersEnd++;
    }
}

LayerHistoryV2::Summary LayerHistoryV2::summarize(nsecs_t now) {
    LayerHistory::Summary summary;

    std::lock_guard lock(mLock);

    partitionLayers(now);

    for (const auto& [layer, info] : activeLayers()) {
        const auto strong = layer.promote();
        if (!strong) {
            continue;
        }

        const bool recent = info->isRecentlyActive(now);
        if (recent) {
            const auto [type, refreshRate] = info->getRefreshRate(now);
            // Skip NoVote layer as those don't have any requirements
            if (type == LayerHistory::LayerVoteType::NoVote) {
                continue;
            }

            // Compute the layer's position on the screen
            const Rect bounds = Rect(strong->getBounds());
            const ui::Transform transform = strong->getTransform();
            constexpr bool roundOutwards = true;
            Rect transformed = transform.transform(bounds, roundOutwards);

            const float layerArea = transformed.getWidth() * transformed.getHeight();
            float weight = mDisplayArea ? layerArea / mDisplayArea : 0.0f;
            summary.push_back({strong->getName(), type, refreshRate, weight});

            if (CC_UNLIKELY(mTraceEnabled)) {
                trace(layer, type, static_cast<int>(std::round(refreshRate)));
            }
        } else if (CC_UNLIKELY(mTraceEnabled)) {
            trace(layer, LayerHistory::LayerVoteType::NoVote, 0);
        }
    }

    return summary;
}

void LayerHistoryV2::partitionLayers(nsecs_t now) {
    const nsecs_t threshold = getActiveLayerThreshold(now);

    // Collect expired and inactive layers after active layers.
    size_t i = 0;
    while (i < mActiveLayersEnd) {
        auto& [weak, info] = mLayerInfos[i];
        if (const auto layer = weak.promote(); layer && isLayerActive(*layer, *info, threshold)) {
            i++;
            // Set layer vote if set
            const auto frameRate = layer->getFrameRate();
            if (frameRate.has_value()) {
                if (*frameRate == Layer::FRAME_RATE_NO_VOTE) {
                    info->setLayerVote(LayerVoteType::NoVote, 0.f);
                } else {
                    info->setLayerVote(LayerVoteType::Explicit, *frameRate);
                }
            } else {
                info->resetLayerVote();
            }
            continue;
        }

        if (CC_UNLIKELY(mTraceEnabled)) {
            trace(weak, LayerHistory::LayerVoteType::NoVote, 0);
        }

        info->clearHistory();
        std::swap(mLayerInfos[i], mLayerInfos[--mActiveLayersEnd]);
    }

    // Collect expired layers after inactive layers.
    size_t end = mLayerInfos.size();
    while (i < end) {
        if (mLayerInfos[i].first.promote()) {
            i++;
        } else {
            std::swap(mLayerInfos[i], mLayerInfos[--end]);
        }
    }

    mLayerInfos.erase(mLayerInfos.begin() + static_cast<long>(end), mLayerInfos.end());
}

void LayerHistoryV2::clear() {
    std::lock_guard lock(mLock);

    for (const auto& [layer, info] : activeLayers()) {
        info->clearHistory();
    }

    mActiveLayersEnd = 0;
}

} // namespace android::scheduler::impl