bsd/sys/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  */
 105
 106 /* Flags to be passed with work_interval_create() */
 107
 108 /* If interval is joinable, create no longer implicitly joins, you must use work_interval_join */
 109 #define WORK_INTERVAL_FLAG_JOINABLE             (0x1)
 110 /* Only threads that join the group are measured together, otherwise the group is the creator's home group */
 111 #define WORK_INTERVAL_FLAG_GROUP                (0x2)
 112
 113 /* Flags to describe the interval flavor to the performance controller */
 114 #define WORK_INTERVAL_TYPE_MASK                 (0xF0000000)
 115 #define WORK_INTERVAL_TYPE_DEFAULT              (0x0 << 28)
 116 #define WORK_INTERVAL_TYPE_COREAUDIO            (0x1 << 28)
 117 #define WORK_INTERVAL_TYPE_COREANIMATION        (0x2 << 28)
 118 #define WORK_INTERVAL_TYPE_CA_RENDER_SERVER     (0x2 << 28)
 119 #define WORK_INTERVAL_TYPE_CA_CLIENT            (0x3 << 28)
 120 #define WORK_INTERVAL_TYPE_HID_DELIVERY         (0x4 << 28)
 121 #define WORK_INTERVAL_TYPE_LAST                 (0xF << 28)
 122
 123 #ifndef KERNEL
 124
 125 typedef struct work_interval *work_interval_t;
 126 typedef struct work_interval_instance *work_interval_instance_t;
 127
 128 /*
 129  * Create a new work interval handle.
 130  *
 131  * May fail with EALREADY if the current group already has a work interval.
 132  *
 133  * With no flags:
 134  *      Auto-joins the work interval to the creating thread
 135  *      May only use interval_handle from creating thread
 136  *      Data provided affects native thread group
 137  *
 138  * With the JOINABLE flag
 139  *      interval_handle is usable by the process
 140  *      creating thread does not auto-join
 141  *      notifying thread must have joined when notifying
 142  *
 143  * With the GROUP flag
 144  *      creates a new thread group to isolate the joined threads from
 145  *      the rest of the process for performance controller analysis
 146  *      Threads which join the work interval become members of this new group
 147  *
 148  * TODO: Add a name parameter so that clients can name the work interval
 149  * Can also take the thread name from the notifying thread
 150  *
 151  * Requires the 'com.apple.private.kernel.work-interval' entitlement (PRIV_WORK_INTERVAL)
 152  *
 153  * Note that joining a work interval supersedes automatic thread group management via vouchers
 154  */
 155 int     work_interval_create(work_interval_t *interval_handle, uint32_t flags);
 156
 157
 158 /*
 159  * Notify the power management subsystem that the work for a current interval has completed
 160  *
 161  * Only the process which created the work interval may notify
 162  */
 163 int     work_interval_notify(work_interval_t    interval_handle,
 164     uint64_t start, uint64_t finish,
 165     uint64_t deadline, uint64_t next_start,
 166     uint32_t flags);
 167
 168 /*
 169  * Notify, with "finish" implicitly set to the current time
 170  *
 171  * Only the process which created the work interval may notify
 172  */
 173 int     work_interval_notify_simple(work_interval_t interval_handle,
 174     uint64_t start, uint64_t deadline,
 175     uint64_t next_start);
 176
 177 /*
 178  * Deallocate work interval handle
 179  * For non-JOINABLE, also removes thread from work interval
 180  * For JOINABLE, does not remove thread (needs a leave as well)
 181  */
 182 int     work_interval_destroy(work_interval_t interval_handle);
 183
 184 /*
 185  * Join work interval via work interval handle
 186  * Only allowed if interval is using the joinable and group flags
 187  *
 188  * Supersedes automatic thread group management via vouchers
 189  */
 190 int     work_interval_join(work_interval_t interval_handle);
 191
 192 /*
 193  * extract Mach send right representing work interval thread group
 194  * Returns a +1 send right ref, which must be deallocated via mach_port_deallocate
 195  * Only allowed if interval is joinable, otherwise returns ENOTSUP
 196  *
 197  * Supersedes automatic thread group management via vouchers
 198  */
 199 int     work_interval_copy_port(work_interval_t interval_handle, mach_port_t *port);
 200
 201 /*
 202  * Join work interval via Mach send right
 203  *
 204  * Does NOT consume Mach send right, must deallocate with mach_port_deallocate after using
 205  * It's safe to deallocate the right after joining, the thread will stay joined
 206  *
 207  * Can be sent to clients via xpc_dictionary_copy_mach_send, and similar
 208  *
 209  * Supersedes automatic thread group management via vouchers
 210  *
 211  * If the underlying work interval object is terminated then this may return ENOENT
 212  * <rdar://problem/31819320>
 213  */
 214 int     work_interval_join_port(mach_port_t port);
 215
 216 /*
 217  * Leave the current thread's work interval
 218  */
 219 int     work_interval_leave(void);
 220
 221 #endif /* !KERNEL */
 222
 223 #if PRIVATE
 224
 225 /* Private interface between Libsyscall and xnu */
 226 #define WORK_INTERVAL_OPERATION_CREATE  0x00000001      /* deprecated */
 227 #define WORK_INTERVAL_OPERATION_DESTROY 0x00000002      /* arg is NULL */
 228 #define WORK_INTERVAL_OPERATION_NOTIFY  0x00000003      /* arg is a work_interval_notification_t */
 229 #define WORK_INTERVAL_OPERATION_CREATE2 0x00000004      /* arg is a work_interval_create_params */
 230 #define WORK_INTERVAL_OPERATION_JOIN    0x00000005      /* arg is a port_name */
 231
 232 struct work_interval_notification {
 233         uint64_t        start;
 234         uint64_t        finish;
 235         uint64_t        deadline;
 236         uint64_t        next_start;
 237         uint32_t        notify_flags;
 238         uint32_t        create_flags;
 239 };
 240 typedef struct work_interval_notification *work_interval_notification_t;
 241
 242 struct work_interval_create_params {
 243         uint64_t        wicp_id;          /* out param */
 244         uint32_t        wicp_port;        /* out param */
 245         uint32_t        wicp_create_flags;
 246 };
 247
 248
 249 int     __work_interval_ctl(uint32_t operation, uint64_t work_interval_id, void *arg, size_t len);
 250
 251 #endif /* PRIVATE */
 252
 253 __END_DECLS
 254
 255 #endif /* _SYS_WORK_INTERVAL_H */