/* * spin4.c * * * Pthreads-win32 - POSIX Threads Library for Win32 * Copyright (C) 1998 Ben Elliston and Ross Johnson * Copyright (C) 1999,2000,2001 Ross Johnson * * Contact Email: rpj@ise.canberra.edu.au * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * -------------------------------------------------------------------------- * * Declare a static spinlock object, lock it, spin on it, * and then unlock it again. */ #include "test.h" #include <sys/timeb.h> pthread_spinlock_t lock = PTHREAD_SPINLOCK_INITIALIZER; struct _timeb currSysTimeStart; struct _timeb currSysTimeStop; #define GetDurationMilliSecs(_TStart, _TStop) ((_TStop.time*1000+_TStop.millitm) \ - (_TStart.time*1000+_TStart.millitm)) static int washere = 0; void * func(void * arg) { _ftime(&currSysTimeStart); assert(pthread_spin_lock(&lock) == 0); assert(pthread_spin_unlock(&lock) == 0); _ftime(&currSysTimeStop); washere = 1; return (void *) GetDurationMilliSecs(currSysTimeStart, currSysTimeStop); } int main() { long result = 0; int i; pthread_t t; int CPUs; if ((CPUs = pthread_num_processors_np()) == 1) { printf("Test not run - it requires multiple CPUs.\n"); exit(0); } assert(pthread_spin_lock(&lock) == 0); assert(pthread_create(&t, NULL, func, NULL) == 0); /* * This should relinqish the CPU to the func thread enough times * to waste approximately 2000 millisecs only if the lock really * is spinning in the func thread (assuming 10 millisec CPU quantum). */ for (i = 0; i < 200; i++) { sched_yield(); } assert(pthread_spin_unlock(&lock) == 0); assert(pthread_join(t, (void **) &result) == 0); assert(result > 1000); assert(pthread_spin_destroy(&lock) == 0); assert(washere == 1); return 0; }