tools/tests/mktimer/mktimer_test.c

   1 /*
   2  * Copyright (c) 2016 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 #include <CoreFoundation/CoreFoundation.h>
  30 #include <unistd.h>
  31 #include <mach/mach.h>
  32 #include <mach/mach_time.h>
  33
  34 /* These externs can be removed once the prototypes make it to the SDK */
  35 extern mach_port_name_t mk_timer_create(void);
  36 extern kern_return_t mk_timer_arm(mach_port_name_t name, uint64_t expire_time);
  37
  38 #define MK_TIMER_CRITICAL (1)
  39 extern kern_return_t    mk_timer_arm_leeway(mach_port_name_t  name,
  40     uint64_t          mk_timer_flags,
  41     uint64_t          mk_timer_expire_time,
  42     uint64_t          mk_timer_leeway);
  43
  44 struct mach_timebase_info tbinfo;
  45 double conversion;
  46
  47 mach_port_t timerPort;
  48
  49 uint64_t interval_abs = 1000000000;
  50
  51 uint32_t use_leeway = 0;
  52 uint32_t report = 1000;
  53
  54 uint64_t on, lastfire = 0, totaljitter = 0, max_jitter = 0, min_jitter = ~0ULL, jiterations = 0, leeway_ns = 0, leeway_abs = 0;
  55 uint64_t deadline;
  56
  57 void
  58 cfmcb(CFMachPortRef port, void *msg, CFIndex size, void *msginfo)
  59 {
  60         uint64_t ctime = mach_absolute_time();
  61         uint64_t jitter = 0;
  62
  63         if (deadline) {
  64                 jitter = (ctime - deadline);
  65                 if (jitter > max_jitter) {
  66                         max_jitter = jitter;
  67                 }
  68
  69                 if (jitter < min_jitter) {
  70                         min_jitter = jitter;
  71                 }
  72
  73                 totaljitter += jitter;
  74                 if ((++jiterations % report) == 0) {
  75                         printf("max_jitter: %g (ns), min_jitter: %g (ns), average_jitter: %g (ns)\n", max_jitter * conversion, min_jitter * conversion, ((double)totaljitter / (double)jiterations) * conversion);
  76                         max_jitter = 0; min_jitter = ~0ULL; jiterations = 0; totaljitter = 0;
  77                 }
  78         }
  79
  80         deadline = mach_absolute_time() + interval_abs;
  81
  82         if (use_leeway) {
  83                 mk_timer_arm_leeway(timerPort, MK_TIMER_CRITICAL, deadline, leeway_abs);
  84         } else {
  85                 mk_timer_arm(timerPort, deadline);
  86         }
  87 }
  88
  89 int
  90 main(int argc, char **argv)
  91 {
  92         if (argc != 4) {
  93                 printf("Usage: mktimer_test <interval_ns> <use leeway trap> <leeway_ns>\n");
  94                 return 0;
  95         }
  96
  97         on = strtoul(argv[1], NULL, 0);
  98         use_leeway = strtoul(argv[2], NULL, 0);
  99
 100         mach_timebase_info(&tbinfo);
 101         conversion = ((double)tbinfo.numer / (double) tbinfo.denom);
 102
 103         leeway_ns = strtoul(argv[3], NULL, 0);
 104
 105         leeway_abs = leeway_ns / conversion;
 106         printf("Interval in ns: %llu, timebase conversion: %g, use leeway syscall: %d, leeway_ns: %llu\n", on, conversion, !!use_leeway, leeway_ns);
 107
 108         interval_abs = on / conversion;
 109
 110         uint64_t cID = 0;
 111         CFMachPortContext context = (CFMachPortContext){
 112                 1,
 113                 (void *)cID,
 114                 NULL,
 115                 NULL,
 116                 NULL,
 117         };
 118
 119         timerPort = mk_timer_create();
 120         CFMachPortRef port = CFMachPortCreateWithPort(NULL, timerPort, cfmcb, &context, NULL);
 121         CFRunLoopSourceRef eventSource = CFMachPortCreateRunLoopSource(NULL, port, -1);
 122         CFRunLoopAddSource(CFRunLoopGetCurrent(), eventSource, kCFRunLoopDefaultMode);
 123         CFRelease(eventSource);
 124
 125         if (use_leeway) {
 126                 mk_timer_arm_leeway(timerPort, MK_TIMER_CRITICAL, mach_absolute_time() + interval_abs, leeway_abs);
 127         } else {
 128                 mk_timer_arm(timerPort, mach_absolute_time() + interval_abs);
 129         }
 130
 131         for (;;) {
 132                 CFRunLoopRun();
 133         }
 134         return 0;
 135 }