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 * Copyright (c) 2011-2018 Apple Computer, Inc. All rights reserved.
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 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
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 * may not be used to create, or enable the creation or redistribution of,
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 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
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#include <kern/thread.h>
#include <stdbool.h>

#define KPERF_PET_DEFAULT_IDLE_RATE 15

extern uint64_t kppet_lightweight_start_time;
extern _Atomic uint32_t kppet_gencount;

/*
 * If `actionid` is non-zero, set up PET to sample the action.  Otherwise,
 * disable PET.
 */
void kppet_config(unsigned int actionid);

/*
 * Reset PET back to its default settings.
 */
void kppet_reset(void);

/*
 * Notify PET that new threads are switching on-CPU.
 */
void kppet_on_cpu(thread_t thread, thread_continue_t continuation,
    uintptr_t *starting_frame);

/*
 * Mark a thread as sampled by PET.
 */
void kppet_mark_sampled(thread_t thread);

/*
 * Wake the PET thread from its timer handler.
 */
void kppet_wake_thread(void);

/*
 * For configuring PET from the sysctl interface.
 */
int kppet_get_idle_rate(void);
int kppet_set_idle_rate(int new_idle_rate);
int kppet_get_lightweight_pet(void);
int kppet_set_lightweight_pet(int on);

/*
 * Update whether lightweight PET is active when turning sampling on and off.
 */
void kppet_lightweight_active_update(void);

/*
 * Notify from kptimer what the PET period is.
 */
void kppet_set_period(uint64_t period);
