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Commit fd4c8c38 authored by Matthew Bouyack's avatar Matthew Bouyack
Browse files

Use snprintf for SurfaceFlinger fence name 

snprintf is significantly faster than String8::format
This change saves ~50us per frame on Android Wear

Change-Id: I6ac47c2434662ca561208daae232f02a9f136aaf
parent 3169437f

include/ui/Fence.h

+3 −0
Original line number Diff line number Diff line
@@ -79,6 +79,9 @@ public: 
    // becomes signaled when both f1 and f2 are signaled (even if f1 or f2 is

    // destroyed before it becomes signaled).  The name argument specifies the

    // human-readable name to associated with the new Fence object.

    static sp<Fence> merge(const char* name, const sp<Fence>& f1,

            const sp<Fence>& f2);



    static sp<Fence> merge(const String8& name, const sp<Fence>& f1,

            const sp<Fence>& f2);

libs/gui/ConsumerBase.cpp

+3 −2
Original line number Diff line number Diff line
@@ -315,9 +315,10 @@ status_t ConsumerBase::addReleaseFenceLocked(int slot, 
    if (!mSlots[slot].mFence.get()) {

        mSlots[slot].mFence = fence;

    } else {

        char fenceName[32] = {};

        snprintf(fenceName, 32, "%.28s:%d", mName.string(), slot);

        sp<Fence> mergedFence = Fence::merge(

                String8::format("%.28s:%d", mName.string(), slot),

                mSlots[slot].mFence, fence);

                fenceName, mSlots[slot].mFence, fence);

        if (!mergedFence.get()) {

            CB_LOGE("failed to merge release fences");

            // synchronization is broken, the best we can do is hope fences

libs/ui/Fence.cpp

+10 −5
Original line number Diff line number Diff line
@@ -72,7 +72,7 @@ status_t Fence::waitForever(const char* logname) { 
    return err < 0 ? -errno : status_t(NO_ERROR);

}



sp<Fence> Fence::merge(const String8& name, const sp<Fence>& f1,

sp<Fence> Fence::merge(const char* name, const sp<Fence>& f1,

        const sp<Fence>& f2) {

    ATRACE_CALL();

    int result;
@@ -80,24 +80,29 @@ sp<Fence> Fence::merge(const String8& name, const sp<Fence>& f1, 
    // valid fence (e.g. NO_FENCE) we merge the one valid fence with itself so

    // that a new fence with the given name is created.

    if (f1->isValid() && f2->isValid()) {

        result = sync_merge(name.string(), f1->mFenceFd, f2->mFenceFd);

        result = sync_merge(name, f1->mFenceFd, f2->mFenceFd);

    } else if (f1->isValid()) {

        result = sync_merge(name.string(), f1->mFenceFd, f1->mFenceFd);

        result = sync_merge(name, f1->mFenceFd, f1->mFenceFd);

    } else if (f2->isValid()) {

        result = sync_merge(name.string(), f2->mFenceFd, f2->mFenceFd);

        result = sync_merge(name, f2->mFenceFd, f2->mFenceFd);

    } else {

        return NO_FENCE;

    }

    if (result == -1) {

        status_t err = -errno;

        ALOGE("merge: sync_merge(\"%s\", %d, %d) returned an error: %s (%d)",

                name.string(), f1->mFenceFd, f2->mFenceFd,

                name, f1->mFenceFd, f2->mFenceFd,

                strerror(-err), err);

        return NO_FENCE;

    }

    return sp<Fence>(new Fence(result));

}



sp<Fence> Fence::merge(const String8& name, const sp<Fence>& f1,

        const sp<Fence>& f2) {

    return merge(name.string(), f1, f2);

}



int Fence::dup() const {

    return ::dup(mFenceFd);

}