1/* 2 * Copyright (c) 2000-2007 Apple Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28/* 29 * @OSF_COPYRIGHT@ 30 */ 31/* 32 * Mach Operating System 33 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University 34 * All Rights Reserved. 35 * 36 * Permission to use, copy, modify and distribute this software and its 37 * documentation is hereby granted, provided that both the copyright 38 * notice and this permission notice appear in all copies of the 39 * software, derivative works or modified versions, and any portions 40 * thereof, and that both notices appear in supporting documentation. 41 * 42 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 43 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 44 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 45 * 46 * Carnegie Mellon requests users of this software to return to 47 * 48 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 49 * School of Computer Science 50 * Carnegie Mellon University 51 * Pittsburgh PA 15213-3890 52 * 53 * any improvements or extensions that they make and grant Carnegie Mellon 54 * the rights to redistribute these changes. 55 */ 56/* 57 */ 58 59#ifndef _KERN_TIMER_H_ 60#define _KERN_TIMER_H_ 61 62#include <kern/kern_types.h> 63 64/* 65 * Some platforms have very expensive timebase routines. An optimization 66 * is to avoid switching timers on kernel exit/entry, which results in all 67 * time billed to the system timer. However, when exposed to userspace, 68 * we report as user time to indicate that work was done on behalf of 69 * userspace. 70 * 71 * Although this policy is implemented as a global variable, we snapshot it 72 * at key points in the thread structure (when the thread is locked and 73 * executing in the kernel) to avoid imbalances. 74 */ 75extern int precise_user_kernel_time; 76 77/* 78 * thread must be locked, or be the current executing thread, so that 79 * it doesn't transition from user to kernel while updating the 80 * thread-local value (or in kernel debugger context). In the future, 81 * we make take into account task-level or thread-level policy. 82 */ 83#define use_precise_user_kernel_time(thread) ( precise_user_kernel_time ) 84 85/* 86 * Definitions for high resolution timers. A check 87 * word on the high portion allows atomic updates. 88 */ 89 90struct timer { 91 uint64_t tstamp; 92#if defined(__LP64__) 93 uint64_t all_bits; 94#else 95 uint32_t low_bits; 96 uint32_t high_bits; 97 uint32_t high_bits_check; 98#endif 99}; 100 101typedef struct timer timer_data_t, *timer_t; 102 103/* 104 * Exported kernel interface to timers 105 */ 106 107/* Start a timer by setting the timestamp */ 108extern void timer_start( 109 timer_t timer, 110 uint64_t tstamp); 111 112/* Stop a timer by updating from the timestamp */ 113extern void timer_stop( 114 timer_t timer, 115 uint64_t tstamp); 116 117/* Update the timer and start a new one */ 118extern void timer_switch( 119 timer_t timer, 120 uint64_t tstamp, 121 timer_t new_timer); 122 123/* Update the thread timer at an event */ 124extern void thread_timer_event( 125 uint64_t tstamp, 126 timer_t new_timer); 127 128/* Initialize a timer */ 129extern void timer_init( 130 timer_t timer); 131 132/* Update a saved timer value and return delta to current value */ 133extern uint64_t timer_delta( 134 timer_t timer, 135 uint64_t *save); 136 137/* Advance a timer by a 64 bit value */ 138extern void timer_advance( 139 timer_t timer, 140 uint64_t delta); 141 142/* 143 * Exported hardware interface to timers 144 */ 145 146/* Read timer value */ 147#if defined(__LP64__) 148static inline uint64_t timer_grab( 149 timer_t timer) 150{ 151 return timer->all_bits; 152} 153#else 154extern uint64_t timer_grab( 155 timer_t timer); 156 157/* Update timer value */ 158extern void timer_update( 159 timer_t timer, 160 uint32_t new_high, 161 uint32_t new_low); 162#endif /* defined(__LP64__) */ 163 164#endif /* _KERN_TIMER_H_ */ 165