Scheduling group cleanup
The C++ API for scheduling groups is going away, so use the C API.
Renumber THREAD_GROUP_* constants to have the same values as SP_*.
They are @hide so this should be OK.
The old THREAD_GROUP_FG_BOOST constant is removed, and replaced by a
(private) THREAD_GROUP_FOREGROUND constant that is just a placeholder
to correspond to SP_FOREGROUND. It is not usable at this level.
Improved performance of android_os_Process_setProcessGroup:
avoid unnecessary syscall to getpriority for each tid.
Fixed error handling in android_os_Process_setThreadGroup.
It raises an exception if set_sched_policy() returns an error.
Add comments and fix typos in existing comments.
Change-Id: Ib922e92c945985c695ef0addbd2b83b8e82865f8
diff --git a/core/java/android/os/Process.java b/core/java/android/os/Process.java
index 770bf1c..8e041bb 100644
--- a/core/java/android/os/Process.java
+++ b/core/java/android/os/Process.java
@@ -266,25 +266,38 @@
*/
public static final int SCHED_IDLE = 5;
- /**
- * Default thread group - gets a 'normal' share of the CPU
- * @hide
- */
- public static final int THREAD_GROUP_DEFAULT = 0;
+ // Keep in sync with SP_* constants of enum type SchedPolicy
+ // declared in system/core/include/cutils/sched_policy.h,
+ // except THREAD_GROUP_DEFAULT does not correspond to any SP_* value.
/**
- * Background non-interactive thread group - All threads in
+ * Default thread group -
+ * has meaning with setProcessGroup() only, cannot be used with setThreadGroup().
+ * When used with setProcessGroup(), the group of each thread in the process
+ * is conditionally changed based on that thread's current priority, as follows:
+ * threads with priority numerically less than THREAD_PRIORITY_BACKGROUND
+ * are moved to foreground thread group. All other threads are left unchanged.
+ * @hide
+ */
+ public static final int THREAD_GROUP_DEFAULT = -1;
+
+ /**
+ * Background thread group - All threads in
* this group are scheduled with a reduced share of the CPU.
+ * Value is same as constant SP_BACKGROUND of enum SchedPolicy.
+ * FIXME rename to THREAD_GROUP_BACKGROUND.
* @hide
*/
- public static final int THREAD_GROUP_BG_NONINTERACTIVE = 1;
+ public static final int THREAD_GROUP_BG_NONINTERACTIVE = 0;
/**
- * Foreground 'boost' thread group - All threads in
- * this group are scheduled with an increased share of the CPU
+ * Foreground thread group - All threads in
+ * this group are scheduled with a normal share of the CPU.
+ * Value is same as constant SP_FOREGROUND of enum SchedPolicy.
+ * Not used at this level.
* @hide
**/
- public static final int THREAD_GROUP_FG_BOOST = 2;
+ private static final int THREAD_GROUP_FOREGROUND = 1;
public static final int SIGNAL_QUIT = 3;
public static final int SIGNAL_KILL = 9;
@@ -672,28 +685,37 @@
/**
* Sets the scheduling group for a thread.
* @hide
- * @param tid The indentifier of the thread/process to change.
- * @param group The target group for this thread/process.
+ * @param tid The identifier of the thread to change.
+ * @param group The target group for this thread from THREAD_GROUP_*.
*
* @throws IllegalArgumentException Throws IllegalArgumentException if
* <var>tid</var> does not exist.
* @throws SecurityException Throws SecurityException if your process does
* not have permission to modify the given thread, or to use the given
* priority.
+ * If the thread is a thread group leader, that is it's gettid() == getpid(),
+ * then the other threads in the same thread group are _not_ affected.
*/
public static final native void setThreadGroup(int tid, int group)
throws IllegalArgumentException, SecurityException;
+
/**
* Sets the scheduling group for a process and all child threads
* @hide
- * @param pid The indentifier of the process to change.
- * @param group The target group for this process.
+ * @param pid The identifier of the process to change.
+ * @param group The target group for this process from THREAD_GROUP_*.
*
* @throws IllegalArgumentException Throws IllegalArgumentException if
* <var>tid</var> does not exist.
* @throws SecurityException Throws SecurityException if your process does
* not have permission to modify the given thread, or to use the given
* priority.
+ *
+ * group == THREAD_GROUP_DEFAULT means to move all non-background priority
+ * threads to the foreground scheduling group, but to leave background
+ * priority threads alone. group == THREAD_GROUP_BG_NONINTERACTIVE moves all
+ * threads, regardless of priority, to the background scheduling group.
+ * group == THREAD_GROUP_FOREGROUND is not allowed.
*/
public static final native void setProcessGroup(int pid, int group)
throws IllegalArgumentException, SecurityException;