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Commit 1f5b95ff authored by Matt Buckley's avatar Matt Buckley
Browse files

Add locking to performance hint NDK 

This patch adds thread safety to the NDK, locking everything behind a
single mutex to avoid multiple lock acquisitions when operating on
shared state. All calls are asynchronous, except for createSession and
setThreads which don't need to hold the lock during their call, so the
risk of contesting the mutex is low.

Test: atest PerformanceHintNativeTest
Bug: 343817997
Change-Id: Ib08c11d6b7c84c30e83cca6613b15c62bcd8a68f
parent 7d217a8a

native/android/performance_hint.cpp

+10 −0
Original line number Diff line number Diff line
@@ -51,6 +51,9 @@ struct APerformanceHintSession; 
constexpr int64_t SEND_HINT_TIMEOUT = std::chrono::nanoseconds(100ms).count();

struct AWorkDuration : public hal::WorkDuration {};



// Shared lock for the whole PerformanceHintManager and sessions

static std::mutex sHintMutex = std::mutex{};



struct APerformanceHintManager {

public:

    static APerformanceHintManager* getInstance();
@@ -192,6 +195,7 @@ APerformanceHintSession* APerformanceHintManager::createSession( 
    }

    auto out = new APerformanceHintSession(mHintManager, std::move(session), mPreferredRateNanos,

                                           initialTargetWorkDurationNanos, sessionConfig);

    std::scoped_lock lock(sHintMutex);

    out->traceThreads(tids);

    out->traceTargetDuration(initialTargetWorkDurationNanos);

    out->tracePowerEfficient(false);
@@ -219,6 +223,7 @@ APerformanceHintSession::APerformanceHintSession(std::shared_ptr<IHintManager> h 
    if (sessionConfig->id > INT32_MAX) {

        ALOGE("Session ID too large, must fit 32-bit integer");

    }

    std::scoped_lock lock(sHintMutex);

    constexpr int numEnums =

            ndk::enum_range<hal::SessionHint>().end() - ndk::enum_range<hal::SessionHint>().begin();

    mLastHintSentTimestamp = std::vector<int64_t>(numEnums, 0);
@@ -244,6 +249,7 @@ int APerformanceHintSession::updateTargetWorkDuration(int64_t targetDurationNano 
              ret.getMessage());

        return EPIPE;

    }

    std::scoped_lock lock(sHintMutex);

    mTargetDurationNanos = targetDurationNanos;

    /**

     * Most of the workload is target_duration dependent, so now clear the cached samples
@@ -267,6 +273,7 @@ int APerformanceHintSession::reportActualWorkDuration(int64_t actualDurationNano 
}



int APerformanceHintSession::sendHint(SessionHint hint) {

    std::scoped_lock lock(sHintMutex);

    if (hint < 0 || hint >= static_cast<int32_t>(mLastHintSentTimestamp.size())) {

        ALOGE("%s: invalid session hint %d", __FUNCTION__, hint);

        return EINVAL;
@@ -305,6 +312,7 @@ int APerformanceHintSession::setThreads(const int32_t* threadIds, size_t size) { 
        return EPIPE;

    }



    std::scoped_lock lock(sHintMutex);

    traceThreads(tids);



    return 0;
@@ -343,6 +351,7 @@ int APerformanceHintSession::setPreferPowerEfficiency(bool enabled) { 
              ret.getMessage());

        return EPIPE;

    }

    std::scoped_lock lock(sHintMutex);

    tracePowerEfficient(enabled);

    return OK;

}
@@ -355,6 +364,7 @@ int APerformanceHintSession::reportActualWorkDurationInternal(AWorkDuration* wor 
    int64_t actualTotalDurationNanos = workDuration->durationNanos;

    int64_t now = uptimeNanos();

    workDuration->timeStampNanos = now;

    std::scoped_lock lock(sHintMutex);

    traceActualDuration(workDuration->durationNanos);

    mActualWorkDurations.push_back(std::move(*workDuration));