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Date:      Tue, 21 Dec 2004 22:15:33 +0300
From:      Castl Troy <mastah@phreaker.net>
To:        hackers@freebsd.org
Subject:   calibrating time
Message-ID:  <6.2.0.7.1.20041221221529.021bb7d0@pop.phreaker.net>
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Hello hackers,

Just want to ask people here who have time to run my program and answer me 
back output from it.
Thanks!

=====

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <sys/time.h>


int main(int argc, char **argv)
{
	u_int i, avg, totaldiff = 0;
	u_int diff[10];
	struct timeval pold, pcur;	

	fprintf(stderr, "Examining sleep()\n");
	
	for(i=0; i<10; i++) {
		gettimeofday(&pold, NULL);
		sleep(1);
		gettimeofday(&pcur, NULL);
		fprintf(stderr, "Pass %2d [ diff: %3lu.%-6lu second(s) ]\n", i, 
pcur.tv_sec - pold.tv_sec,
			pcur.tv_usec - pold.tv_usec);
		diff[i] = pcur.tv_usec - pold.tv_usec;
	}
	for(i=0; i<10; i++)
		totaldiff+=diff[i];
	avg = totaldiff / 10;
	fprintf(stderr, "        -- average diff: %5u microsecond(s)\n", avg);
	
	fprintf(stderr, "\nExamining usleep()\n");
	
	for(i=1;i<11; i++) {
		gettimeofday(&pold, NULL);
		usleep(1 * 1000 * 1000);
		gettimeofday(&pcur, NULL);
		fprintf(stderr, "Pass %2d [ diff: %3lu.%-6lu second(s) ]\n", i, 
pcur.tv_sec - pold.tv_sec,
			pcur.tv_usec - pold.tv_usec);
		diff[i] = pcur.tv_usec - pold.tv_usec;
	}
	for(i=0; i<10; i++)
		totaldiff+=diff[i];
	avg = totaldiff / 10;
	fprintf(stderr, "        -- average diff: %5u microsecond(s)\n", avg);
	
	exit(0);
}

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