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/*
* benchtest5.c
*
* Measure time taken to complete an elementary operation.
*
* - Semaphore
* Single thread iteration over post/wait for a semaphore.
*/
#include "test.h"
#include <sys/timeb.h>
#ifdef __GNUC__
#include <stdlib.h>
#endif
#include "benchtest.h"
#define ITERATIONS 10000000L
sem_t sema;
struct _timeb currSysTimeStart;
struct _timeb currSysTimeStop;
long durationMilliSecs;
long overHeadMilliSecs = 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
reportTest (char * testNameString)
{
durationMilliSecs = GetDurationMilliSecs(currSysTimeStart, currSysTimeStop) - overHeadMilliSecs;
printf( "%-40s %15ld %15.3f\n",
testNameString,
durationMilliSecs,
(float) durationMilliSecs * 1E3 / ITERATIONS);
}
int
main (int argc, char *argv[])
{
printf( "========================================================================\n");
printf( "\nOperations on a semaphore.\n%ld iterations\n\n",
ITERATIONS);
printf( "%-40s %15s %15s\n",
"Test",
"Total(msec)",
"average(usec)");
printf( "------------------------------------------------------------------------\n");
/*
* Time the loop overhead so we can subtract it from the actual test times.
*/
TESTSTART
assert(1 == 1);
TESTSTOP
durationMilliSecs = GetDurationMilliSecs(currSysTimeStart, currSysTimeStop) - overHeadMilliSecs;
overHeadMilliSecs = durationMilliSecs;
/*
* Now we can start the actual tests
*/
assert(sem_init(&sema, 0, 0) == 0);
TESTSTART
assert(sem_post(&sema) == 0);
TESTSTOP
assert(sem_destroy(&sema) == 0);
reportTest("Post");
assert(sem_init(&sema, 0, ITERATIONS) == 0);
TESTSTART
assert(sem_wait(&sema) == 0);
TESTSTOP
assert(sem_destroy(&sema) == 0);
reportTest("Wait without blocking");
/*
* Time the loop overhead so we can subtract it from the actual test times.
*/
TESTSTART
assert(1 == 1);
assert(1 == 1);
TESTSTOP
durationMilliSecs = GetDurationMilliSecs(currSysTimeStart, currSysTimeStop) - overHeadMilliSecs;
overHeadMilliSecs = durationMilliSecs;
/*
* Now we can start the actual tests
*/
assert(sem_init(&sema, 0, 0) == 0);
TESTSTART
assert(sem_post(&sema) == 0);
assert(sem_wait(&sema) == 0);
TESTSTOP
assert(sem_destroy(&sema) == 0);
reportTest("Post then Wait without blocking");
assert(sem_init(&sema, 0, 1) == 0);
TESTSTART
assert(sem_wait(&sema) == 0);
assert(sem_post(&sema) == 0);
TESTSTOP
assert(sem_destroy(&sema) == 0);
reportTest("Wait then Post without blocking");
printf( "========================================================================\n");
/*
* End of tests.
*/
return 0;
}
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