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/*
* 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@
*/
#include <dispatch/dispatch.h>
#include <stdio.h>
#if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
#include <unistd.h>
#ifdef __ANDROID__
#include <linux/sysctl.h>
#else
#if !defined(__linux__)
#include <sys/sysctl.h>
#endif
#endif /* __ANDROID__ */
#endif
#include <stdlib.h>
#include <assert.h>
#ifdef __APPLE__
#include <libkern/OSAtomic.h>
#endif
#include <sys/types.h>
#include <bsdtests.h>
#include "dispatch_test.h"
static volatile int32_t busy_threads_started, busy_threads_finished;
/*
* Keep a thread busy, spinning on the CPU.
*/
static volatile int all_done = 0;
/* Fiddling with j in the middle and hitting this global will hopefully keep
* the optimizer from cutting the whole thing out as dead code.
*/
static volatile unsigned int busythread_useless;
static void busythread(void *ignored)
{
(void)ignored;
/* prevent i and j been optimized out */
volatile uint64_t i = 0, j = 0;
OSAtomicIncrement32(&busy_threads_started);
while(!all_done)
{
if(i == 500000) { j -= busythread_useless; }
j += i;
i += 1;
}
(void)j;
OSAtomicIncrement32(&busy_threads_finished);
}
/*
* Test that dispatch_apply can make progress and finish, even if there are
* so many other running and unblocked workqueue threads that the apply's
* helper threads never get a chance to come up.
*
* <rdar://problem/10718199> dispatch_apply should not block waiting on other
* threads while calling thread is available
*/
static void test_apply_contended(dispatch_queue_t dq)
{
uint32_t activecpu;
#if defined(__linux__) || defined(__OpenBSD__)
activecpu = (uint32_t)sysconf(_SC_NPROCESSORS_ONLN);
#elif defined(_WIN32)
SYSTEM_INFO si;
GetSystemInfo(&si);
activecpu = si.dwNumberOfProcessors;
#else
size_t s = sizeof(activecpu);
sysctlbyname("hw.activecpu", &activecpu, &s, NULL, 0);
#endif
int tIndex, n_threads = (int)activecpu;
dispatch_group_t grp = dispatch_group_create();
for(tIndex = 0; tIndex < n_threads; tIndex++) {
dispatch_group_async_f(grp, dq, NULL, busythread);
}
// Spin until all the threads have actually started
while(busy_threads_started < n_threads) {
usleep(1);
}
volatile __block int32_t count = 0;
const int32_t final = 32;
int32_t before = busy_threads_started;
dispatch_apply(final, dq, ^(size_t i __attribute__((unused))) {
OSAtomicIncrement32(&count);
});
int32_t after = busy_threads_finished;
test_long("contended: threads started before apply", before, n_threads);
test_long("contended: count", count, final);
test_long("contended: threads finished before apply", after, 0);
/* Release busy threads by setting all_done to 1 */
all_done = 1;
dispatch_group_wait(grp, DISPATCH_TIME_FOREVER);
dispatch_release(grp);
}
int
main(void)
{
dispatch_test_start("Dispatch Apply");
volatile __block int32_t count = 0;
const int32_t final = 32;
dispatch_queue_t queue = dispatch_get_global_queue(0, 0);
test_ptr_notnull("dispatch_get_global_queue", queue);
dispatch_apply(final, queue, ^(size_t i __attribute__((unused))) {
OSAtomicIncrement32(&count);
});
test_long("count", count, final);
count = 0; // rdar://problem/9294578
dispatch_apply(final, queue, ^(size_t i __attribute__((unused))) {
dispatch_apply(final, queue, ^(size_t ii __attribute__((unused))) {
dispatch_apply(final, queue, ^(size_t iii __attribute__((unused))) {
OSAtomicIncrement32(&count);
});
});
});
test_long("nested count", count, final * final * final);
test_apply_contended(queue);
test_stop();
return 0;
}
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