commit 22752851180b26f8d797b3fe5f7e99ad0eeaf7ee
author Tim Murray <timmurray@google.com> Thu May 04 13:38:49 2017 -0700
committer Tim Murray <timmurray@google.com> Thu May 04 13:38:49 2017 -0700
tree 85cc65ba2732e216c5d8d2fa386e02de99112ada
parent 8bba03d323684abb4e209398019c2540b053b827

surfaceflinger: make EventThread FIFO

Jitter in EventThread scheduling was contributing to SystemUI jank.

Test: thread is FIFO
bug 36631902

Change-Id: I930c729b27403ef8941e9a1e0ef8ec57a3d323a0

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index bc4e6c5..3e30ebd 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -548,12 +548,15 @@
         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

diff --git a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
index 019c8e3..7070b97 100644
--- a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
+++ b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
@@ -520,13 +520,15 @@
     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.