commit 71906aac8532b80b43a04582eb3ad1e92acdaa7a
author Yifan Hong <elsk@google.com> Mon Apr 10 11:49:21 2017 -0700
committer Iliyan Malchev <malchev@google.com> Tue Apr 11 16:28:35 2017 +0000
tree f1095d81730801be4b2054a56fb2e75867359944
parent 99dfb8a6466b653afc63ed91f07f59daa3c66385

android.frameworks.sensorservice@1.0: Looper thread SCHED_FIFO

Looper thread uses SCHED_FIFO with a priority 10.

Test: sensor works (sanity checks with camera app), logcat
      doesn't show SCHED_FIFO could not be used

b/34386025 [Treble] Identify and fix Binder usage by camera HALs that isn't NDK-based
b/35219747 [Treble] Figure out the new interface between camera and sensor
b/36651814 [QCOM Treble] [REDACTED] Camera HAL uses Binder
b/36651420 [QCOM Treble] [REDACTED] location daemon uses Binder

Change-Id: I0f236a77cccdc8d67a933daf7d5046947c82a3cf

services/sensorservice/hidl/SensorManager.cpp

diff --git a/services/sensorservice/hidl/SensorManager.cpp b/services/sensorservice/hidl/SensorManager.cpp
index 0743fc3..06ff95c 100644
--- a/services/sensorservice/hidl/SensorManager.cpp
+++ b/services/sensorservice/hidl/SensorManager.cpp
@@ -22,12 +22,14 @@
 
 #include "SensorManager.h"
 
+#include <sched.h>
+
+#include <thread>
+
 #include "EventQueue.h"
 #include "DirectReportChannel.h"
 #include "utils.h"
 
-#include <thread>
-
 namespace android {
 namespace frameworks {
 namespace sensorservice {
@@ -131,6 +133,14 @@
         std::condition_variable looperSet;
 
         std::thread{[&mutex = mLooperMutex, &looper = mLooper, &looperSet] {
+
+            struct sched_param p = {0};
+            p.sched_priority = 10;
+            if (sched_setscheduler(0 /* current thread*/, SCHED_FIFO, &p) != 0) {
+                LOG(WARNING) << "Could not use SCHED_FIFO for looper thread: "
+                        << strerror(errno);
+            }
+
             std::unique_lock<std::mutex> lock(mutex);
             looper = Looper::prepare(ALOOPER_PREPARE_ALLOW_NON_CALLBACKS /* opts */);
             lock.unlock();