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_hwc1.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
index d84d4e1..69fb8c5 100644
--- a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
+++ b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
@@ -459,6 +459,18 @@
     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");
+    }
+
+
     // Initialize the H/W composer object.  There may or may not be an
     // actual hardware composer underneath.
     mHwc = new HWComposer(this,