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/*
* itest - timed test program for use with bench2
* Copyright (C) 2007 Red Hat Inc.
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/time.h>
#include <stdlib.h>
#include <sys/resource.h>
#include <unistd.h>
#include <pthread.h>
#include <semaphore.h>
#include <sched.h>
typedef unsigned long long uint64;
struct timeval tstart, tstop;
pthread_t tester[256];
sem_t go;
int ncpus;
int iterations;
void start(void)
{
gettimeofday (&tstart, NULL);
}
uint64 usecs (struct timeval *tv)
{
return tv->tv_sec * 1000000 + tv->tv_usec;
}
uint64 stop(void)
{
gettimeofday (&tstop, NULL);
return usecs(&tstop) - usecs(&tstart);
}
void usage(char *name)
{
printf ("Usage %s [num_threads] [total_iterations]\n", name);
printf("%s will call sys_getuid() total_iterations [default 2,000,000]\n", name);
printf("times divided across num_threads [default 1].\n\n");
exit(1);
}
void *null_thread (void *data)
{
int cpu;
cpu_set_t cpu_mask;
int thread_num = (int)(long)data;
cpu = thread_num % ncpus;
CPU_ZERO(&cpu_mask);
CPU_SET(cpu, &cpu_mask);
if( sched_setaffinity( 0, sizeof(cpu_mask), &cpu_mask ) < 0 ) {
perror("sched_setaffinity");
}
// fprintf(stderr, "starting thread %d on cpu %d num=%d\n", thread_num, cpu, iterations);
while (sem_wait(&go) == -1) ;
return NULL;
}
void *caller_thread (void *data)
{
int i, cpu;
cpu_set_t cpu_mask;
int thread_num = (int)(long)data;
/* Force threads to be distributed across all cpus. */
/* The scheduler would probably do the right thing without this. */
cpu = thread_num % ncpus;
CPU_ZERO(&cpu_mask);
CPU_SET(cpu, &cpu_mask);
if( sched_setaffinity( 0, sizeof(cpu_mask), &cpu_mask ) < 0 ) {
perror("sched_setaffinity");
}
// fprintf(stderr, "starting thread %d on cpu %d num=%d\n", thread_num, cpu, iterations);
while (sem_wait(&go) == -1) ;
for (i = 0; i < iterations; i++)
getuid();
return NULL;
}
int main(int argc, char *argv[])
{
int i, n = 1;
uint64 nsecs, null_usecs, caller_usecs;
int total_iterations = 2000000;
if (argc > 3)
usage(argv[0]);
if (argc >= 2) {
n = strtol(argv[1], NULL, 10);
if (n <= 0)
usage(argv[0]);
}
if (argc > 2) {
total_iterations = strtol(argv[2], NULL, 10);
if (total_iterations < 100000)
usage(argv[0]);
}
ncpus = sysconf(_SC_NPROCESSORS_ONLN);
sem_init (&go, 0, 0);
iterations = total_iterations/n;
for (i = 0; i < n; i++) {
if (pthread_create(&tester[i], NULL, null_thread, (void *)(long)i) < 0) {
perror("Error creating thread");
return -1;
}
}
start();
for (i = 0; i < n; i++)
sem_post (&go);
for (i = 0; i < n; i++)
pthread_join(tester[i], NULL);
null_usecs = stop();
for (i = 0; i < n; i++) {
if (pthread_create(&tester[i], NULL, caller_thread, (void *)(long)i) < 0) {
perror("Error creating thread");
return -1;
}
}
start();
for (i = 0; i < n; i++)
sem_post (&go);
for (i = 0; i < n; i++)
pthread_join(tester[i], NULL);
caller_usecs = stop();
/* returns nanosecs per call */
nsecs = ((caller_usecs - null_usecs) * 1000LL) / ((uint64)(n * iterations));
printf("%lld\n", nsecs);
return 0;
}
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