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/*
* stress1.c
*
*
* --------------------------------------------------------------------------
*
* Pthreads-win32 - POSIX Threads Library for Win32
* Copyright(C) 1998 John E. Bossom
* Copyright(C) 1999,2005 Pthreads-win32 contributors
*
* Contact Email: rpj@callisto.canberra.edu.au
*
* The current list of contributors is contained
* in the file CONTRIBUTORS included with the source
* code distribution. The list can also be seen at the
* following World Wide Web location:
* http://sources.redhat.com/pthreads-win32/contributors.html
*
* 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 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 in the file COPYING.LIB;
* if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*
* --------------------------------------------------------------------------
*
* Test Synopsis:
* - Stress test condition variables, mutexes, semaphores.
*
* Test Method (Validation or Falsification):
* - Validation
*
* Requirements Tested:
* - Correct accounting of semaphore and condition variable waiters.
*
* Features Tested:
* -
*
* Cases Tested:
* -
*
* Description:
* Attempting to expose race conditions in cond vars, semaphores etc.
* - Master attempts to signal slave close to when timeout is due.
* - Master and slave do battle continuously until main tells them to stop.
* - Afterwards, the CV must be successfully destroyed (will return an
* error if there are waiters (including any internal semaphore waiters,
* which, if there are, cannot be real waiters).
*
* Environment:
* -
*
* Input:
* - None.
*
* Output:
* - File name, Line number, and failed expression on failure.
* - No output on success.
*
* Assumptions:
* -
*
* Pass Criteria:
* - CV is successfully destroyed.
*
* Fail Criteria:
* - CV destroy fails.
*/
#include "test.h"
#include <string.h>
#include <sys/timeb.h>
const unsigned int ITERATIONS = 1000;
static pthread_t master, slave;
typedef struct {
int value;
pthread_cond_t cv;
pthread_mutex_t mx;
} mysig_t;
static int allExit;
static mysig_t control = {0, PTHREAD_COND_INITIALIZER, PTHREAD_MUTEX_INITIALIZER};
static pthread_barrier_t startBarrier, readyBarrier, holdBarrier;
static int timeoutCount = 0;
static int signalsTakenCount = 0;
static int signalsSent = 0;
static int bias = 0;
static int timeout = 10; // Must be > 0
enum {
CTL_STOP = -1
};
/*
* Returns abstime 'milliseconds' from 'now'.
*
* Works for: -INT_MAX <= millisecs <= INT_MAX
*/
struct timespec *
millisecondsFromNow (struct timespec * time, int millisecs)
{
struct _timeb currSysTime;
int64_t nanosecs, secs;
const int64_t NANOSEC_PER_MILLISEC = 1000000;
const int64_t NANOSEC_PER_SEC = 1000000000;
/* get current system time and add millisecs */
_ftime(&currSysTime);
secs = (int64_t)(currSysTime.time) + (millisecs / 1000);
nanosecs = ((int64_t) (millisecs%1000 + currSysTime.millitm)) * NANOSEC_PER_MILLISEC;
if (nanosecs >= NANOSEC_PER_SEC)
{
secs++;
nanosecs -= NANOSEC_PER_SEC;
}
else if (nanosecs < 0)
{
secs--;
nanosecs += NANOSEC_PER_SEC;
}
time->tv_nsec = (long)nanosecs;
time->tv_sec = (long)secs;
return time;
}
void *
masterThread (void * arg)
{
int dither = (int) (size_t) arg;
timeout = (int) (size_t) arg;
pthread_barrier_wait(&startBarrier);
do
{
int sleepTime;
assert(pthread_mutex_lock(&control.mx) == 0);
control.value = timeout;
assert(pthread_mutex_unlock(&control.mx) == 0);
/*
* We are attempting to send the signal close to when the slave
* is due to timeout. We feel around by adding some [non-random] dither.
*
* dither is in the range 2*timeout peak-to-peak
* sleep time is the average of timeout plus dither.
* e.g.
* if timeout = 10 then dither = 20 and
* sleep millisecs is: 5 <= ms <= 15
*
* The bias value attempts to apply some negative feedback to keep
* the ratio of timeouts to signals taken close to 1:1.
* bias changes more slowly than dither so as to average more.
*
* Finally, if abs(bias) exceeds timeout then timeout is incremented.
*/
if (signalsSent % timeout == 0)
{
if (timeoutCount > signalsTakenCount)
{
bias++;
}
else if (timeoutCount < signalsTakenCount)
{
bias--;
}
if (bias < -timeout || bias > timeout)
{
timeout++;
}
}
dither = (dither + 1 ) % (timeout * 2);
sleepTime = (timeout - bias + dither) / 2;
Sleep(sleepTime);
assert(pthread_cond_signal(&control.cv) == 0);
signalsSent++;
pthread_barrier_wait(&holdBarrier);
pthread_barrier_wait(&readyBarrier);
}
while (!allExit);
return NULL;
}
void *
slaveThread (void * arg)
{
struct timespec time;
pthread_barrier_wait(&startBarrier);
do
{
assert(pthread_mutex_lock(&control.mx) == 0);
if (pthread_cond_timedwait(&control.cv,
&control.mx,
millisecondsFromNow(&time, control.value)) == ETIMEDOUT)
{
timeoutCount++;
}
else
{
signalsTakenCount++;
}
assert(pthread_mutex_unlock(&control.mx) == 0);
pthread_barrier_wait(&holdBarrier);
pthread_barrier_wait(&readyBarrier);
}
while (!allExit);
return NULL;
}
int
main ()
{
unsigned int i;
assert(pthread_barrier_init(&startBarrier, NULL, 3) == 0);
assert(pthread_barrier_init(&readyBarrier, NULL, 3) == 0);
assert(pthread_barrier_init(&holdBarrier, NULL, 3) == 0);
assert(pthread_create(&master, NULL, masterThread, (void *) (size_t) timeout) == 0);
assert(pthread_create(&slave, NULL, slaveThread, NULL) == 0);
allExit = FALSE;
pthread_barrier_wait(&startBarrier);
for (i = 1; !allExit; i++)
{
pthread_barrier_wait(&holdBarrier);
if (i >= ITERATIONS)
{
allExit = TRUE;
}
pthread_barrier_wait(&readyBarrier);
}
assert(pthread_join(slave, NULL) == 0);
assert(pthread_join(master, NULL) == 0);
printf("Signals sent = %d\nWait timeouts = %d\nSignals taken = %d\nBias = %d\nTimeout = %d\n",
signalsSent,
timeoutCount,
signalsTakenCount,
(int) bias,
timeout);
/* Cleanup */
assert(pthread_barrier_destroy(&holdBarrier) == 0);
assert(pthread_barrier_destroy(&readyBarrier) == 0);
assert(pthread_barrier_destroy(&startBarrier) == 0);
assert(pthread_cond_destroy(&control.cv) == 0);
assert(pthread_mutex_destroy(&control.mx) == 0);
/* Success. */
return 0;
}
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