commit 41a3853cea0cffede422fc2692b9c8e1674fc5eb
author Tim Murray <timmurray@google.com> Wed Jun 22 12:42:10 2016 -0700
committer Tim Murray <timmurray@google.com> Thu Jul 07 12:39:55 2016 -0700
tree 1ce2afe425a41a9d586393b11c11f962f3797ec0
parent 70ccba596c586b7effde1ff99d36c911873b4ed4

surfaceflinger: make critical threads SCHED_FIFO

Sets the main thread, EventThread, and SFEventThread to SCHED_FIFO to
minimize jitter.

bug 24503801

Change-Id: I3751c00c79482842f5c0bdaec92b6cbfe62328a0

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index c541668..37b3757 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -462,6 +462,18 @@
         mSFEventThread = new EventThread(sfVsyncSrc, *this);
         mEventQueue.setEventThread(mSFEventThread);
 
+        // set EventThread and SFEventThread to SCHED_FIFO for minimum jitter
+        struct sched_param param = {0};
+        param.sched_priority = 1;
+        if (sched_setscheduler(mEventThread->getTid(), SCHED_FIFO, &param) != 0) {
+            ALOGE("Couldn't set SCHED_FIFO for EventThread");
+        }
+
+        if (sched_setscheduler(mSFEventThread->getTid(), SCHED_FIFO, &param) != 0) {
+            ALOGE("Couldn't set SCHED_FIFO for SFEventThread");
+        }
+
+
         // Get a RenderEngine for the given display / config (can't fail)
         mRenderEngine = RenderEngine::create(mEGLDisplay,
                 HAL_PIXEL_FORMAT_RGBA_8888);