services/surfaceflinger/SurfaceTracing.cpp

/*
 * Copyright 2017 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 "SurfaceTracing"
#define ATRACE_TAG ATRACE_TAG_GRAPHICS

#include "SurfaceTracing.h"

#include <android-base/file.h>
#include <log/log.h>
#include <utils/SystemClock.h>
#include <utils/Trace.h>

namespace android {

void SurfaceTracing::enable() {
    ATRACE_CALL();
    std::lock_guard<std::mutex> protoGuard(mTraceMutex);

    if (mEnabled) {
        return;
    }
    mEnabled = true;

    mTrace = std::make_unique<LayersTraceFileProto>();
    mTrace->set_magic_number(uint64_t(LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_H) << 32 |
                             LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_L);
}

status_t SurfaceTracing::disable() {
    ATRACE_CALL();
    std::lock_guard<std::mutex> protoGuard(mTraceMutex);

    if (!mEnabled) {
        return NO_ERROR;
    }
    mEnabled = false;
    status_t err(writeProtoFileLocked());
    ALOGE_IF(err == PERMISSION_DENIED, "Could not save the proto file! Permission denied");
    ALOGE_IF(err == NOT_ENOUGH_DATA, "Could not save the proto file! There are missing fields");
    mTrace.reset();
    return err;
}

bool SurfaceTracing::isEnabled() const {
    std::lock_guard<std::mutex> protoGuard(mTraceMutex);
    return mEnabled;
}

void SurfaceTracing::traceLayers(const char* where, LayersProto layers) {
    std::lock_guard<std::mutex> protoGuard(mTraceMutex);
    if (!mEnabled) {
        return;
    }
    LayersTraceProto* entry = mTrace->add_entry();
    entry->set_elapsed_realtime_nanos(elapsedRealtimeNano());
    entry->set_where(where);
    entry->mutable_layers()->Swap(&layers);

    constexpr int maxBufferedEntryCount = 3600;
    if (mTrace->entry_size() >= maxBufferedEntryCount) {
        // TODO: flush buffered entries without disabling tracing
        ALOGE("too many buffered frames; force disable tracing");
        mEnabled = false;
        writeProtoFileLocked();
        mTrace.reset();
    }
}

status_t SurfaceTracing::writeProtoFileLocked() {
    ATRACE_CALL();

    if (!mTrace->IsInitialized()) {
        return NOT_ENOUGH_DATA;
    }
    std::string output;
    if (!mTrace->SerializeToString(&output)) {
        return PERMISSION_DENIED;
    }
    if (!android::base::WriteStringToFile(output, mOutputFileName, true)) {
        return PERMISSION_DENIED;
    }

    return NO_ERROR;
}

void SurfaceTracing::dump(String8& result) const {
    std::lock_guard<std::mutex> protoGuard(mTraceMutex);

    result.appendFormat("Tracing state: %s\n", mEnabled ? "enabled" : "disabled");
    result.appendFormat("  number of entries: %d\n", mTrace ? mTrace->entry_size() : 0);
}

} // namespace android