#define _GNU_SOURCE
#include <features.h>
#include <sys/time.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sched.h>
#include <libgen.h>

int set_affinity(unsigned int cpu)
{
	int rc = 0;
	cpu_set_t set;
	CPU_ZERO(&set);
	CPU_SET(cpu, &set);

#ifdef MAKE_RHEL3
	if (sched_setaffinity(0, &set) != 0)
#else
	if (sched_setaffinity(0, sizeof(set), &set) != 0)
#endif
	{
		rc = 1;
		fprintf(stderr,
		        "failed to set CPU mask to %x: %s\n",
		        cpu, strerror(errno));
	}

	return rc;
}


int main(int argc, char *argv[])
{
	unsigned int tsleep = 0;
	unsigned int i;
	int max_cpu;
	struct timeval tv;

	if (argc < 2) {
		printf("usage: %s ncpus [sleeptime]\n", basename(argv[0]));
		return 1;
	}

	max_cpu = atoi(argv[1]);
	if (max_cpu == 0)
		return 2;

	if (argc > 2)
		tsleep = atoi(argv[2]);

	while(1) {

		printf("\n");
		for (i = 0; i < max_cpu; ++i) {

			if (set_affinity(i) != 0)
				break;

			if (gettimeofday(&tv, NULL) != 0)
				printf("gettimeofday failed\n");
			else
				printf("cpu %d: %ld.%06ld\n", i, tv.tv_sec, tv.tv_usec);
		}

		if (!tsleep)
			break;

		sleep(tsleep);
	}

	return 0;
}