dispatch-1.0/testing/dispatch_timer_short.c

   1 /*
   2  * Copyright (c) 2010-2011 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_APACHE_LICENSE_HEADER_START@
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  *
  18  * @APPLE_APACHE_LICENSE_HEADER_END@
  19  */
  20
  21 #include <stdlib.h>
  22 #include <assert.h>
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <math.h>
  26 #include <mach/mach_time.h>
  27 #include <libkern/OSAtomic.h>
  28
  29 #include <dispatch/dispatch.h>
  30
  31 #include <bsdtests.h>
  32 #include "dispatch_test.h"
  33
  34 #define delay (1ull * NSEC_PER_SEC)
  35 #define interval (5ull * NSEC_PER_USEC)
  36
  37 #define N 100000
  38
  39 static dispatch_source_t t[N];
  40 static dispatch_queue_t q;
  41 static dispatch_group_t g;
  42
  43 static volatile int32_t count;
  44 static mach_timebase_info_data_t tbi;
  45 static uint64_t start, last;
  46
  47 #define elapsed_ms(x) (((now-(x))*tbi.numer/tbi.denom)/(1000ull*NSEC_PER_USEC))
  48
  49 void
  50 test_fin(void *cxt)
  51 {
  52         fprintf(stderr, "Called back every %llu us on average\n",
  53                         (delay/count)/NSEC_PER_USEC);
  54         test_long_less_than("Frequency", 1, ceil((double)delay/(count*interval)));
  55         int i;
  56         for (i = 0; i < N; i++) {
  57                 dispatch_source_cancel(t[i]);
  58                 dispatch_release(t[i]);
  59         }
  60         dispatch_resume(q);
  61         dispatch_release(q);
  62         dispatch_release(g);
  63         test_ptr("finalizer ran", cxt, cxt);
  64         test_stop();
  65 }
  66
  67 void
  68 test_short_timer(void)
  69 {
  70         // Add a large number of timers with suspended target queue in front of
  71         // the timer being measured <rdar://problem/7401353>
  72         g = dispatch_group_create();
  73         q = dispatch_queue_create("q", NULL);
  74         int i;
  75         for (i = 0; i < N; i++) {
  76                 t[i] = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, q);
  77                 dispatch_source_set_timer(t[i], DISPATCH_TIME_NOW, interval, 0);
  78                 dispatch_group_enter(g);
  79                 dispatch_source_set_registration_handler(t[i], ^{
  80                         dispatch_suspend(t[i]);
  81                         dispatch_group_leave(g);
  82                 });
  83                 dispatch_resume(t[i]);
  84         }
  85         // Wait for registration & configuration of all timers
  86         dispatch_group_wait(g, DISPATCH_TIME_FOREVER);
  87         dispatch_suspend(q);
  88         for (i = 0; i < N; i++) {
  89                 dispatch_resume(t[i]);
  90         }
  91
  92         dispatch_source_t s = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER,
  93                         0, 0, dispatch_get_global_queue(0, 0));
  94         test_ptr_notnull("dispatch_source_create", s);
  95         dispatch_source_set_timer(s, DISPATCH_TIME_NOW, interval, 0);
  96         dispatch_source_set_event_handler(s, ^{
  97                 uint64_t now = mach_absolute_time();
  98                 if (!count) {
  99                         dispatch_after(dispatch_time(DISPATCH_TIME_NOW, delay),
 100                                         dispatch_get_global_queue(0, 0), ^{
 101                                 dispatch_source_cancel(s);
 102                                 dispatch_release(s);
 103                         });
 104                         fprintf(stderr, "First timer callback  (after %4llu ms)\n",
 105                                         elapsed_ms(start));
 106                 }
 107                 OSAtomicIncrement32(&count);
 108                 if (elapsed_ms(last) >= 100) {
 109                         fprintf(stderr, "%5d timer callbacks (after %4llu ms)\n", count,
 110                                         elapsed_ms(start));
 111                         last = now;
 112                 }
 113         });
 114         dispatch_set_context(s, s);
 115         dispatch_set_finalizer_f(s, test_fin);
 116         fprintf(stderr, "Scheduling %llu us timer\n", interval/NSEC_PER_USEC);
 117         start = last = mach_absolute_time();
 118         dispatch_resume(s);
 119 }
 120
 121 int
 122 main(void)
 123 {
 124         dispatch_test_start("Dispatch Short Timer"); // <rdar://problem/7765184>
 125         mach_timebase_info(&tbi);
 126         test_short_timer();
 127         dispatch_main();
 128         return 0;
 129 }