work_interval.h
1 /* 2 * Copyright (c) 2015-2017 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 #ifndef _SYS_WORK_INTERVAL_H 30 #define _SYS_WORK_INTERVAL_H 31 32 #include <stdint.h> 33 #include <sys/cdefs.h> 34 #include <sys/_types/_size_t.h> 35 36 #include <mach/port.h> 37 38 __BEGIN_DECLS 39 40 /* 41 * A work interval is a repeatable unit of work characterized by a 42 * start, finish, and deadline. 43 * 44 * Trusted clients with deadline-sensitive work may report information 45 * about the execution of their work using the work interval facility. 46 * This is intended to be a higher-level semantic than realtime scheduling, 47 * which operates at the level of thread block/unblock. A high level 48 * operation may have many blocking points, including IPC to other tasks, 49 * and this this metric will capture the overall time to complete a unit of 50 * work. 51 * 52 * A work interval is defined by several timestamps, namely (S)tart, 53 * (F)inish, (D)eadline, and (N)ext start. 54 * 55 * ... ----+==================+--------+--+==== ... 56 * | | | | 57 * S F D N 58 * 59 * \__________________/ 60 * Active 61 * \___________________________/ 62 * Work Interval 63 * 64 * \_________/ 65 * | 66 * report information here ---------+ 67 * 68 * Definitions: 69 * 70 * Start: Absolute time when the current deadline-oriented work began. Due 71 * to scheduling latency, preemption, and blocking points, the 72 * thread controlling the work interval may actually begin 73 * executing after this ideal time (which may be the previous work 74 * interval's "next start") 75 * Finish: Absolute time when the current deadline-oriented work finished. 76 * This will typically be a timestamp taken before reporting using 77 * the work interval interface. 78 * Deadline: Absolute time by which the current work was expected to finish. 79 * In cases where the amount of computation (or preemption, or time 80 * spent blocked) causes the active period to take longer than 81 * expected, F may be greater than D. 82 * Next start: Absolute time when the next deadline-oriented work is 83 * expected to begin. This is typically the same as Deadline. 84 * Active: The fraction of the work interval spent completing the work. In 85 * cases where the Finish time exceeded the Deadline, this fraction 86 * will be >1.0. 87 * 88 * Basic Use: 89 * 90 * Clients should report information for a work interval after finishing 91 * work for the current interval but before the next work interval begins. 92 * 93 * If Finish far exceeds the previously expected Deadline, the 94 * caller may adjust Next Start to align to a multiple of the period 95 * (and skip over several work intervals that could not be 96 * executed). 97 * 98 * Caution (!): 99 * 100 * Because the information supplied via this facility directly influences power 101 * management decisions, clients should strive to be as accurate as possible. 102 * Failure to do so will adversely impact system power and performance. 103 * 104 * Work Interval Auto Join Support: 105 * 106 * Work intervals support an optional flag WORK_INTERVAL_FLAG_ENABLE_AUTO_JOIN 107 * which allows RT threads from the same home thread group to join work 108 * intervals via wakeup relationship tracking. Based on the join policy, 109 * RT threads can temporarily join the work interval of other RT threads 110 * which make them runnable. The auto joined thread remains in the work 111 * interval until it blocks or terminates. The mechanism works through 112 * make runnable heuristic and it should be used with extreme caution. 113 * If a client specifies this flag, it gives up explicit control over its 114 * thread group membership and threads unrelated to the work interval 115 * could become part of the thread group. This could lead to serious power 116 * and performance issues. If the make runnable heuristic does not work 117 * for a client use case, it should adopt work_interval_join_port() or 118 * work_interval_join() to explicitly declare its intent. 119 * 120 * Work Interval Deferred Finish Support: 121 * 122 * Another advanced feature for work intervals is the ability to defer the finish 123 * calls for the work interval until all auto-joined threads for the work interval 124 * have blocked or terminated. This feature is enabled via an optional flag 125 * WORK_INTERVAL_FLAG_ENABLE_DEFERRED_FINISH and is valid only if the work interval 126 * is configured with the WORK_INTERVAL_FLAG_ENABLE_AUTO_JOIN flag as well. The 127 * deferred finish mechanism allows the work interval to defer the finish call 128 * for the work interval until all auto-join threads have blocked/terminated 129 * (and have therefore un-joined the work interval) or one of the work interval 130 * threads calls start for the next frame. The deferred finish works only for 131 * workloads that have no temporal overlap across frames i.e. previous frame has to 132 * finish before next frame can start. This feature should be used with caution 133 * since auto-joined threads would delay finish calls to the performance controller 134 * which could lead to poor performance and battery life. 135 */ 136 137 /* Flags to be passed with work_interval_create() */ 138 139 /* If interval is joinable, create no longer implicitly joins, you must use work_interval_join */ 140 #define WORK_INTERVAL_FLAG_JOINABLE (0x1) 141 /* Only threads that join the group are measured together, otherwise the group is the creator's home group */ 142 #define WORK_INTERVAL_FLAG_GROUP (0x2) 143 /* Specifies that the work interval is being created by a client who doesn't 144 * necessarily have the PRIV_WORK_INTERVAL entitlement. Skip privilege checks. 145 * This can only be masked in for work intervals of types COREAUDIO, CA_CLIENT 146 * and DEFAULT */ 147 #define WORK_INTERVAL_FLAG_UNRESTRICTED (0x4) 148 149 /* [Advanced Flag] Read section on "Work Interval Auto Join Support" above for details */ 150 #define WORK_INTERVAL_FLAG_ENABLE_AUTO_JOIN (0x8) 151 /* [Advanced Flag] Read section on "Work Interval Deferred Finish Support" above for details */ 152 #define WORK_INTERVAL_FLAG_ENABLE_DEFERRED_FINISH (0x10) 153 154 /* Kernel-supplied flag: Work interval has been ignored by the kernel */ 155 #define WORK_INTERVAL_FLAG_IGNORED (0x20) 156 157 /* Specifies that the work interval requests the system to provide just enough performance 158 * to be able to finish at the provided deadline and no sooner. */ 159 #define WORK_INTERVAL_FLAG_FINISH_AT_DEADLINE (0x40) 160 161 /* Flags to describe the interval flavor to the performance controller */ 162 #define WORK_INTERVAL_TYPE_MASK (0xF0000000) 163 #define WORK_INTERVAL_TYPE_DEFAULT (0x0 << 28) 164 #define WORK_INTERVAL_TYPE_COREAUDIO (0x1 << 28) 165 #define WORK_INTERVAL_TYPE_COREANIMATION (0x2 << 28) 166 #define WORK_INTERVAL_TYPE_CA_RENDER_SERVER (0x2 << 28) 167 #define WORK_INTERVAL_TYPE_CA_CLIENT (0x3 << 28) 168 #define WORK_INTERVAL_TYPE_HID_DELIVERY (0x4 << 28) 169 #define WORK_INTERVAL_TYPE_COREMEDIA (0x5 << 28) 170 #define WORK_INTERVAL_TYPE_ARKIT (0x6 << 28) 171 #define WORK_INTERVAL_TYPE_LAST (0xF << 28) 172 173 #ifndef KERNEL 174 175 typedef struct work_interval *work_interval_t; 176 typedef struct work_interval_instance *work_interval_instance_t; 177 178 /* 179 * Create a new work interval handle. 180 * 181 * May fail with EALREADY if the current group already has a work interval. 182 * 183 * With no flags: 184 * Auto-joins the work interval to the creating thread 185 * May only use interval_handle from creating thread 186 * Data provided affects native thread group 187 * 188 * With the JOINABLE flag 189 * interval_handle is usable by the process 190 * creating thread does not auto-join 191 * notifying thread must have joined when notifying 192 * 193 * With the GROUP flag 194 * creates a new thread group to isolate the joined threads from 195 * the rest of the process for performance controller analysis 196 * Threads which join the work interval become members of this new group 197 * 198 * TODO: Add a name parameter so that clients can name the work interval 199 * Can also take the thread name from the notifying thread 200 * 201 * Requires the 'com.apple.private.kernel.work-interval' entitlement (PRIV_WORK_INTERVAL) 202 * 203 * Note that joining a work interval supersedes automatic thread group management via vouchers 204 */ 205 int work_interval_create(work_interval_t *interval_handle, uint32_t flags); 206 207 /* Returns the flags used for the work interval when it was created. 208 * 209 * May fail with EINVAL if the port isn't from a prior call to 210 * work_interval_copy_port. 211 */ 212 int work_interval_get_flags_from_port(mach_port_t port, uint32_t *flags); 213 214 215 /* 216 * Notify the power management subsystem that the work for a current interval has completed 217 * 218 * Only the process which created the work interval may notify 219 */ 220 int work_interval_notify(work_interval_t interval_handle, 221 uint64_t start, uint64_t finish, 222 uint64_t deadline, uint64_t next_start, 223 uint32_t flags); 224 225 /* 226 * Notify, with "finish" implicitly set to the current time 227 * 228 * Only the process which created the work interval may notify 229 */ 230 int work_interval_notify_simple(work_interval_t interval_handle, 231 uint64_t start, uint64_t deadline, 232 uint64_t next_start); 233 234 /* 235 * Deallocate work interval handle 236 * For non-JOINABLE, also removes thread from work interval 237 * For JOINABLE, does not remove thread (needs a leave as well) 238 */ 239 int work_interval_destroy(work_interval_t interval_handle); 240 241 /* 242 * Join work interval via work interval handle 243 * Only allowed if interval is using the joinable and group flags 244 * 245 * Supersedes automatic thread group management via vouchers 246 */ 247 int work_interval_join(work_interval_t interval_handle); 248 249 /* 250 * extract Mach send right representing work interval thread group 251 * Returns a +1 send right ref, which must be deallocated via mach_port_deallocate 252 * Only allowed if interval is joinable, otherwise returns ENOTSUP 253 * 254 * Supersedes automatic thread group management via vouchers 255 */ 256 int work_interval_copy_port(work_interval_t interval_handle, mach_port_t *port); 257 258 /* 259 * Join work interval via Mach send right 260 * 261 * Does NOT consume Mach send right, must deallocate with mach_port_deallocate after using 262 * It's safe to deallocate the right after joining, the thread will stay joined 263 * 264 * Can be sent to clients via xpc_dictionary_copy_mach_send, and similar 265 * 266 * Supersedes automatic thread group management via vouchers 267 * 268 * If the underlying work interval object is terminated then this may return ENOENT 269 * <rdar://problem/31819320> 270 */ 271 int work_interval_join_port(mach_port_t port); 272 273 /* 274 * Leave the current thread's work interval 275 */ 276 int work_interval_leave(void); 277 278 #endif /* !KERNEL */ 279 280 #if PRIVATE 281 282 /* Private interface between Libsyscall and xnu */ 283 #define WORK_INTERVAL_OPERATION_CREATE 0x00000001 /* deprecated */ 284 #define WORK_INTERVAL_OPERATION_DESTROY 0x00000002 /* arg is NULL */ 285 #define WORK_INTERVAL_OPERATION_NOTIFY 0x00000003 /* arg is a work_interval_notification_t */ 286 #define WORK_INTERVAL_OPERATION_CREATE2 0x00000004 /* arg is a work_interval_create_params */ 287 #define WORK_INTERVAL_OPERATION_JOIN 0x00000005 /* arg is a port_name */ 288 #define WORK_INTERVAL_OPERATION_GET_FLAGS 0x00000009 /* arg is a port name */ 289 290 struct work_interval_notification { 291 uint64_t start; 292 uint64_t finish; 293 uint64_t deadline; 294 uint64_t next_start; 295 uint32_t notify_flags; 296 uint32_t create_flags; 297 }; 298 typedef struct work_interval_notification *work_interval_notification_t; 299 300 struct work_interval_create_params { 301 uint64_t wicp_id; /* in/out param */ 302 mach_port_name_t wicp_port; /* in/out param */ 303 uint32_t wicp_create_flags; 304 }; 305 306 307 int __work_interval_ctl(uint32_t operation, uint64_t work_interval_id, void *arg, size_t len); 308 309 #endif /* PRIVATE */ 310 311 __END_DECLS 312 313 #endif /* _SYS_WORK_INTERVAL_H */