Add C++ thread API androidGetThreadSchedulingGroup
This API is intended for applications that need to read a thread's
scheduling group, while using the higher-level (C++) family of thread APIs.
Change-Id: I5e58017f74c3989b20b5b1cc2bc4483c95720520
diff --git a/include/utils/threads.h b/include/utils/threads.h
index c8e9c04..79e02eb 100644
--- a/include/utils/threads.h
+++ b/include/utils/threads.h
@@ -142,6 +142,13 @@
// in either case errno is set. Thread ID zero means current thread.
extern int androidSetThreadPriority(pid_t tid, int prio);
+// Get the current scheduling group of a particular thread. Normally returns
+// one of the ANDROID_TGROUP constants other than ANDROID_TGROUP_DEFAULT.
+// Returns ANDROID_TGROUP_DEFAULT if no pthread support (e.g. on host) or if
+// scheduling groups are disabled. Returns INVALID_OPERATION if unexpected error.
+// Thread ID zero means current thread.
+extern int androidGetThreadSchedulingGroup(pid_t tid);
+
#ifdef __cplusplus
}
#endif
diff --git a/libs/utils/Threads.cpp b/libs/utils/Threads.cpp
index 50312e7..6d5067b 100644
--- a/libs/utils/Threads.cpp
+++ b/libs/utils/Threads.cpp
@@ -367,6 +367,41 @@
return rc;
}
+int androidGetThreadSchedulingGroup(pid_t tid)
+{
+ int ret = ANDROID_TGROUP_DEFAULT;
+
+#if defined(HAVE_PTHREADS)
+ // convention is to not call get/set_sched_policy methods if disabled by property
+ pthread_once(&gDoSchedulingGroupOnce, checkDoSchedulingGroup);
+ if (gDoSchedulingGroup) {
+ SchedPolicy policy;
+ // get_sched_policy does not support tid == 0
+ if (tid == 0) {
+ tid = androidGetTid();
+ }
+ if (get_sched_policy(tid, &policy) < 0) {
+ ret = INVALID_OPERATION;
+ } else {
+ switch (policy) {
+ case SP_BACKGROUND:
+ ret = ANDROID_TGROUP_BG_NONINTERACT;
+ break;
+ case SP_FOREGROUND:
+ ret = ANDROID_TGROUP_FG_BOOST;
+ break;
+ default:
+ // should not happen, as enum SchedPolicy does not have any other values
+ ret = INVALID_OPERATION;
+ break;
+ }
+ }
+ }
+#endif
+
+ return ret;
+}
+
namespace android {
/*