libcutils/include/cutils/sched_policy.h

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef __CUTILS_SCHED_POLICY_H
#define __CUTILS_SCHED_POLICY_H

#include <stdbool.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Check if Linux kernel enables CPUSETS feature.
 *
 * Return value: 1 if Linux kernel CONFIG_CPUSETS=y; 0 otherwise.
 */
extern bool cpusets_enabled();

/*
 * Check if Linux kernel enables SCHEDTUNE feature (only available in Android
 * common kernel or Linaro LSK, not in mainline Linux as of v4.9)
 *
 * Return value: 1 if Linux kernel CONFIG_SCHEDTUNE=y; 0 otherwise.
 */
extern bool schedboost_enabled();

/* Keep in sync with THREAD_GROUP_* in frameworks/base/core/java/android/os/Process.java */
typedef enum {
    SP_DEFAULT    = -1,
    SP_BACKGROUND = 0,
    SP_FOREGROUND = 1,
    SP_SYSTEM     = 2,  // can't be used with set_sched_policy()
    SP_AUDIO_APP  = 3,
    SP_AUDIO_SYS  = 4,
    SP_TOP_APP    = 5,
    SP_RT_APP     = 6,
    SP_CNT,
    SP_MAX        = SP_CNT - 1,
    SP_SYSTEM_DEFAULT = SP_FOREGROUND,
} SchedPolicy;

extern int set_cpuset_policy(int tid, SchedPolicy policy);

/* Assign thread tid to the cgroup associated with the specified policy.
 * 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.
 * On platforms which support gettid(), zero tid means current thread.
 * Return value: 0 for success, or -errno for error.
 */
extern int set_sched_policy(int tid, SchedPolicy policy);

/* Return the policy associated with the cgroup of thread tid via policy pointer.
 * On platforms which support gettid(), zero tid means current thread.
 * Return value: 0 for success, or -1 for error and set errno.
 */
extern int get_sched_policy(int tid, SchedPolicy *policy);

/* Return a displayable string corresponding to policy.
 * Return value: non-NULL NUL-terminated name of unspecified length;
 * the caller is responsible for displaying the useful part of the string.
 */
extern const char *get_sched_policy_name(SchedPolicy policy);

#ifdef __cplusplus
}
#endif

#endif /* __CUTILS_SCHED_POLICY_H */