afb81b8278
Some checks failed
Docker. / Ubuntu (push) Has been cancelled
User-agent updater. / User-agent (push) Failing after 15s
Lock Threads / lock (push) Failing after 10s
Waiting for answer. / waiting-for-answer (push) Failing after 22s
Close stale issues and PRs / stale (push) Successful in 13s
Needs user action. / needs-user-action (push) Failing after 8s
Can't reproduce. / cant-reproduce (push) Failing after 8s
103 lines
2.8 KiB
C
103 lines
2.8 KiB
C
/*
|
|
* Copyright (c) 2008-2011 Apple Inc. All rights reserved.
|
|
*
|
|
* @APPLE_APACHE_LICENSE_HEADER_START@
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*
|
|
* @APPLE_APACHE_LICENSE_HEADER_END@
|
|
*/
|
|
|
|
#ifdef __APPLE__
|
|
#include <mach/mach_time.h>
|
|
#endif
|
|
#include <dispatch/dispatch.h>
|
|
#if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
|
|
#include <sys/time.h>
|
|
#include <unistd.h>
|
|
#endif
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#ifdef __APPLE__
|
|
#include <TargetConditionals.h>
|
|
#endif
|
|
#include <bsdtests.h>
|
|
#include "dispatch_test.h"
|
|
|
|
#if LENIENT_DEADLINES
|
|
#define ACCEPTABLE_DRIFT 0.1
|
|
#else
|
|
#define ACCEPTABLE_DRIFT 0.001
|
|
#endif
|
|
|
|
int
|
|
main(int argc __attribute__((unused)), char* argv[] __attribute__((unused)))
|
|
{
|
|
__block uint32_t count = 0;
|
|
__block double last_jitter = 0;
|
|
__block double drift_sum = 0;
|
|
#if defined(_WIN32)
|
|
// 25 times a second (Windows timer resolution is poor)
|
|
uint64_t interval = 1000000000 / 25;
|
|
#else
|
|
// 100 times a second
|
|
uint64_t interval = 1000000000 / 100;
|
|
#endif
|
|
double interval_d = interval / 1000000000.0;
|
|
// for 25 seconds
|
|
unsigned int target = (unsigned int)(25.0 / interval_d);
|
|
|
|
dispatch_test_start("Dispatch Timer Drift");
|
|
|
|
dispatch_source_t t = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_get_main_queue());
|
|
test_ptr_notnull("dispatch_source_create", t);
|
|
|
|
dispatch_source_set_timer(t, dispatch_time(DISPATCH_TIME_NOW, (int64_t)interval), interval, 0);
|
|
|
|
dispatch_source_set_event_handler(t, ^{
|
|
struct timeval now_tv;
|
|
static double first = 0;
|
|
gettimeofday(&now_tv, NULL);
|
|
double now = now_tv.tv_sec + now_tv.tv_usec / 1000000.0;
|
|
|
|
if (count == 0) {
|
|
// Because this is taken at 1st timer fire,
|
|
// later jitter values may be negitave.
|
|
// This doesn't effect the drift calculation.
|
|
first = now;
|
|
}
|
|
double goal = first + interval_d * count;
|
|
double jitter = goal - now;
|
|
double drift = jitter - last_jitter;
|
|
drift_sum += drift;
|
|
|
|
printf("%4d: jitter %f, drift %f\n", count, jitter, drift);
|
|
|
|
if (target <= ++count) {
|
|
drift_sum /= count - 1;
|
|
if (drift_sum < 0) {
|
|
drift_sum = -drift_sum;
|
|
}
|
|
double acceptable_drift = ACCEPTABLE_DRIFT;
|
|
test_double_less_than("drift", drift_sum, acceptable_drift);
|
|
test_stop();
|
|
}
|
|
last_jitter = jitter;
|
|
});
|
|
|
|
dispatch_resume(t);
|
|
|
|
dispatch_main();
|
|
return 0;
|
|
}
|