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/*
* benchtest1.c
*
* Measure time taken to complete an elementary operation.
*
* - Mutex
* Two threads iterate over lock/unlock for each mutex type.
* The two threads are forced into lock-step using two mutexes,
* forcing the threads to block on each lock operation. The
* time measured is therefore the worst case senario.
*/
#include "test.h"
#include <sys/timeb.h>
#ifdef __GNUC__
#include <stdlib.h>
#endif
#define ITERATIONS 100000L
pthread_mutex_t gate1, gate2;
pthread_mutexattr_t ma;
long durationMilliSecs;
long overHeadMilliSecs = 0;
struct _timeb currSysTimeStart;
struct _timeb currSysTimeStop;
pthread_t worker;
int running = 0;
#define GetDurationMilliSecs(_TStart, _TStop) ((_TStop.time*1000+_TStop.millitm) \
- (_TStart.time*1000+_TStart.millitm))
/*
* Dummy use of j, otherwise the loop may be removed by the optimiser
* when doing the overhead timing with an empty loop.
*/
#define TESTSTART \
{ int i, j = 0, k = 0; _ftime(&currSysTimeStart); for (i = 0; i < ITERATIONS; i++) { j++;
#define TESTSTOP \
}; _ftime(&currSysTimeStop); if (j + k == i) j++; }
void *
overheadThread(void * arg)
{
do
{
sched_yield();
}
while (running);
return NULL;
}
void *
workerThread(void * arg)
{
do
{
(void) pthread_mutex_lock(&gate1);
(void) pthread_mutex_lock(&gate2);
(void) pthread_mutex_unlock(&gate1);
sched_yield();
(void) pthread_mutex_unlock(&gate2);
}
while (running);
return NULL;
}
void
runTest (char * testNameString, int mType)
{
#ifdef PTHREAD_MUTEX_DEFAULT
pthread_mutexattr_settype(&ma, mType);
#endif
pthread_mutex_init(&gate1, &ma);
pthread_mutex_init(&gate2, &ma);
(void) pthread_mutex_lock(&gate1);
(void) pthread_mutex_lock(&gate2);
running = 1;
(void) pthread_create(&worker, NULL, workerThread, NULL);
TESTSTART
(void) pthread_mutex_unlock(&gate1);
sched_yield();
(void) pthread_mutex_unlock(&gate2);
(void) pthread_mutex_lock(&gate1);
(void) pthread_mutex_lock(&gate2);
TESTSTOP
running = 0;
(void) pthread_mutex_unlock(&gate2);
(void) pthread_mutex_unlock(&gate1);
(void) pthread_join(worker, NULL);
pthread_mutex_destroy(&gate2);
pthread_mutex_destroy(&gate1);
durationMilliSecs = GetDurationMilliSecs(currSysTimeStart, currSysTimeStop)
- overHeadMilliSecs;
printf( "%-25s %15ld %15ld %15.3f\n",
testNameString,
ITERATIONS,
durationMilliSecs,
(float) durationMilliSecs * 1E3 / ITERATIONS / 4 /* Four locks/unlocks per iteration */);
}
int
main (int argc, char *argv[])
{
pthread_mutexattr_init(&ma);
printf( "Two threads, blocking mutex locks/unlocks.\n\n");
printf( "%-25s %15s %15s %15s\n",
"Test",
"Iterations",
"Total(msec)",
"lock/unlock(usec)");
/*
* Time the loop overhead so we can subtract it from the actual test times.
*/
running = 1;
(void) pthread_create(&worker, NULL, overheadThread, NULL);
TESTSTART
sched_yield();
TESTSTOP
running = 0;
(void) pthread_join(worker, NULL);
pthread_mutex_destroy(&gate2);
pthread_mutex_destroy(&gate1);
durationMilliSecs = GetDurationMilliSecs(currSysTimeStart, currSysTimeStop)
- overHeadMilliSecs;
printf( "%-25s %15ld %15ld\n",
"Overhead",
ITERATIONS,
durationMilliSecs);
overHeadMilliSecs = durationMilliSecs;
/*
* Now we can start the actual tests
*/
#ifdef PTHREAD_MUTEX_DEFAULT
runTest("PTHREAD_MUTEX_DEFAULT", PTHREAD_MUTEX_DEFAULT);
runTest("PTHREAD_MUTEX_NORMAL", PTHREAD_MUTEX_NORMAL);
runTest("PTHREAD_MUTEX_ERRORCHECK", PTHREAD_MUTEX_ERRORCHECK);
runTest("PTHREAD_MUTEX_RECURSIVE", PTHREAD_MUTEX_RECURSIVE);
#else
runTest("Blocking locks", 0);
#endif
/*
* End of tests.
*/
pthread_mutexattr_destroy(&ma);
return 0;
}
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