services/gpuservice/tracing/GpuMemTracer.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 "GpuMemTracer"
#define ATRACE_TAG ATRACE_TAG_GRAPHICS

#include "tracing/GpuMemTracer.h"

#include <gpumem/GpuMem.h>
#include <perfetto/trace/android/gpu_mem_event.pbzero.h>
#include <perfetto/trace/trace.pb.h>
#include <unistd.h>

#include <thread>

PERFETTO_DEFINE_DATA_SOURCE_STATIC_MEMBERS(android::GpuMemTracer::GpuMemDataSource);

namespace android {

std::mutex GpuMemTracer::sTraceMutex;
std::condition_variable GpuMemTracer::sCondition;
bool GpuMemTracer::sTraceStarted;

void GpuMemTracer::initialize(std::shared_ptr<GpuMem> gpuMem) {
    if (!gpuMem->isInitialized()) {
        ALOGE("Cannot initialize GpuMemTracer before GpuMem");
        return;
    }
    mGpuMem = gpuMem;
    perfetto::TracingInitArgs args;
    args.backends = perfetto::kSystemBackend;
    perfetto::Tracing::Initialize(args);
    registerDataSource();
    std::thread tracerThread(&GpuMemTracer::threadLoop, this, true);
    pthread_setname_np(tracerThread.native_handle(), "GpuMemTracerThread");
    tracerThread.detach();
    tracerThreadCount++;
}

void GpuMemTracer::initializeForTest(std::shared_ptr<GpuMem> gpuMem) {
    mGpuMem = gpuMem;
    perfetto::TracingInitArgs args;
    args.backends = perfetto::kInProcessBackend;
    perfetto::Tracing::Initialize(args);
    registerDataSource();
    std::thread tracerThread(&GpuMemTracer::threadLoop, this, false);
    pthread_setname_np(tracerThread.native_handle(), "GpuMemTracerThreadForTest");
    tracerThread.detach();
    tracerThreadCount++;
}

std::vector<perfetto::protos::TracePacket> GpuMemTracer::readGpuMemTotalPacketsForTestBlocking(
        perfetto::TracingSession* tracingSession) {
    std::vector<char> raw_trace = tracingSession->ReadTraceBlocking();
    perfetto::protos::Trace trace;
    trace.ParseFromArray(raw_trace.data(), int(raw_trace.size()));

    std::vector<perfetto::protos::TracePacket> packets;
    for (const auto& packet : trace.packet()) {
        if (!packet.has_gpu_mem_total_event()) {
            continue;
        }
        packets.emplace_back(packet);
    }
    return packets;
}

// Each tracing session can be used for a single block of Start -> Stop.
std::unique_ptr<perfetto::TracingSession> GpuMemTracer::getTracingSessionForTest() {
    perfetto::TraceConfig cfg;
    cfg.set_duration_ms(500);
    cfg.add_buffers()->set_size_kb(1024);
    auto* ds_cfg = cfg.add_data_sources()->mutable_config();
    ds_cfg->set_name(GpuMemTracer::kGpuMemDataSource);

    auto tracingSession = perfetto::Tracing::NewTrace(perfetto::kInProcessBackend);
    tracingSession->Setup(cfg);
    return tracingSession;
}

void GpuMemTracer::registerDataSource() {
    perfetto::DataSourceDescriptor dsd;
    dsd.set_name(kGpuMemDataSource);
    GpuMemDataSource::Register(dsd);
}

void GpuMemTracer::threadLoop(bool infiniteLoop) {
    do {
        {
            std::unique_lock<std::mutex> lock(GpuMemTracer::sTraceMutex);
            while (!sTraceStarted) {
                sCondition.wait(lock);
            }
        }
        traceInitialCounters();
        {
            std::lock_guard<std::mutex> lock(GpuMemTracer::sTraceMutex);
            sTraceStarted = false;
        }
    } while (infiniteLoop);

    // Thread loop is exiting. Reduce the tracerThreadCount to reflect the number of active threads
    // in the wait loop.
    tracerThreadCount--;
}

void GpuMemTracer::traceInitialCounters() {
    if (!mGpuMem->isInitialized()) {
        // This should never happen.
        ALOGE("Cannot trace without GpuMem initialization");
        return;
    }
    mGpuMem->traverseGpuMemTotals([](int64_t ts, uint32_t gpuId, uint32_t pid, uint64_t size) {
        GpuMemDataSource::Trace([&](GpuMemDataSource::TraceContext ctx) {
            auto packet = ctx.NewTracePacket();
            packet->set_timestamp(ts);
            auto* event = packet->set_gpu_mem_total_event();
            event->set_gpu_id(gpuId);
            event->set_pid(pid);
            event->set_size(size);
        });
    });
    // Flush the TraceContext. The last packet in the above loop will go
    // missing without this flush.
    GpuMemDataSource::Trace([](GpuMemDataSource::TraceContext ctx) { ctx.Flush(); });
}

} // namespace android