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Commit 22752851 authored May 04, 2017 by Tim Murray

surfaceflinger: make EventThread FIFO

Jitter in EventThread scheduling was contributing to SystemUI jank.

Test: thread is FIFO
bug 36631902

Change-Id: I930c729b27403ef8941e9a1e0ef8ec57a3d323a0

parent 8bba03d3

services/surfaceflinger/SurfaceFlinger.cpp

+4 −1

Original line number	Diff line number	Diff line
		@@ -548,12 +548,15 @@ void SurfaceFlinger::init() {
		mSFEventThread = new EventThread(sfVsyncSrc, *this, true);
		mEventQueue.setEventThread(mSFEventThread);

		// set SFEventThread to SCHED_FIFO to minimize jitter
		// set EventThread and SFEventThread to SCHED_FIFO to minimize jitter
		struct sched_param param = {0};
		param.sched_priority = 2;
		if (sched_setscheduler(mSFEventThread->getTid(), SCHED_FIFO, &param) != 0) {
		ALOGE("Couldn't set SCHED_FIFO for SFEventThread");
		}
		if (sched_setscheduler(mEventThread->getTid(), SCHED_FIFO, &param) != 0) {
		ALOGE("Couldn't set SCHED_FIFO for EventThread");
		}

		// Get a RenderEngine for the given display / config (can't fail)
		mRenderEngine = RenderEngine::create(mEGLDisplay,

services/surfaceflinger/SurfaceFlinger_hwc1.cpp

+4 −2

Original line number	Diff line number	Diff line
		@@ -520,13 +520,15 @@ void SurfaceFlinger::init() {
		mSFEventThread = new EventThread(sfVsyncSrc, *this, true);
		mEventQueue.setEventThread(mSFEventThread);

		// set SFEventThread to SCHED_FIFO to minimize jitter
		// set EventThread and SFEventThread to SCHED_FIFO to minimize jitter
		struct sched_param param = {0};
		param.sched_priority = 2;
		if (sched_setscheduler(mSFEventThread->getTid(), SCHED_FIFO, &param) != 0) {
		ALOGE("Couldn't set SCHED_FIFO for SFEventThread");
		}

		if (sched_setscheduler(mEventThread->getTid(), SCHED_FIFO, &param) != 0) {
		ALOGE("Couldn't set SCHED_FIFO for EventThread");
		}

		// Initialize the H/W composer object. There may or may not be an
		// actual hardware composer underneath.