/* * Copyright (c) 2015 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * 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 * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * 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 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ #ifndef _SYS_WORK_INTERVAL_H #define _SYS_WORK_INTERVAL_H #include <stdint.h> #include <sys/types.h> #include <sys/cdefs.h> __BEGIN_DECLS /* * Trusted clients with deadline-sensitive work may report information * about the execution of their work using the work interval facility. * This is intended to be a higher-level semantic than realtime scheduling, * which operates at the level of thread block/unblock. A high level * operation may have many blocking points, including IPC to other tasks, * and this this metric will capture the overall time to complete a unit of * work. * * A work interval is defined by several timestamps, namely (S)tart, * (F)inish, (D)eadline, and (N)ext start. * * ... ----+==================+--------+--+==== ... * | | | | * S F D N * * \__________________/ * Active * \___________________________/ * Work Interval * * \_________/ * | * report information here ---------+ * * Definitions: * * Start: Absolute time when the current deadline-oriented work began. Due * to scheduling latency, preemption, and blocking points, the * thread controlling the work interval may actually begin * executing after this ideal time (which may be the previous work * interval's "next start") * Finish: Absolute time when the current deadline-oriented work finished. * This will typically be a timestamp taken before reporting using * the work interval interface. * Deadline: Absolute time by which the current work was expected to finish. * In cases where the amount of computation (or preemption, or time * spent blocked) causes the active period to take longer than * expected, F may be greater than D. * Next start: Absolute time when the next deadline-oriented work is * expected to begin. This is typically the same as Deadline. * Active: The fraction of the work interval spent completing the work. In * cases where the Finish time exceeded the Deadline, this fraction * will be >1.0. * * Basic Use: * * Clients should report information for a work interval after finishing * work for the current interval but before the next work interval begins. * * If Finish far exceeds the previously expected Deadline, the * caller may adjust Next Start to align to a multiple of the period * (and skip over several work intervals that could not be * executed). * * Caution (!): * * Because the information supplied via this facility directly influences power * management decisions, clients should strive to be as accurate as possible. * Failure to do so will adversely impact system power and performance. * */ #ifndef KERNEL typedef struct work_interval *work_interval_t; /* Create a new work interval handle (currently for the current thread only). Flags is unused */ int work_interval_create(work_interval_t *interval_handle, uint32_t flags); /* Notify the power management subsystem that the work for a current interval has completed */ int work_interval_notify(work_interval_t interval_handle, uint64_t start, uint64_t finish, uint64_t deadline, uint64_t next_start, uint32_t flags); /* Notify, with "finish" implicitly set to the current time */ int work_interval_notify_simple(work_interval_t interval_handle, uint64_t start, uint64_t deadline, uint64_t next_start); /* Deallocate work interval (currently for the current thread only) */ int work_interval_destroy(work_interval_t interval_handle); #endif /* KERNEL */ #if PRIVATE /* Private interface between Libsyscall and xnu */ #define WORK_INTERVAL_OPERATION_CREATE 0x00000001 /* arg is a uint64_t * that accepts work interval ID as an OUT param */ #define WORK_INTERVAL_OPERATION_DESTROY 0x00000002 #define WORK_INTERVAL_OPERATION_NOTIFY 0x00000003 /* arg is a work_interval_notification_t */ struct work_interval_notification { uint64_t start; uint64_t finish; uint64_t deadline; uint64_t next_start; uint32_t flags; uint32_t unused1; }; typedef struct work_interval_notification *work_interval_notification_t; int __work_interval_ctl(uint32_t operation, uint64_t work_interval_id, void *arg, size_t len); #endif /* PRIVATE */ __END_DECLS #endif /* _SYS_WORK_INTERVAL_H */