lkml.org 
[lkml]   [2001]   [Mar]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subjectstrange nonmonotonic behavior of gettimeoftheday
Date
I've got following problem with 2.2.17 (Redhat stock kernel)
Linux ***** 2.2.17-14 #1 Mon Feb 5 14:57:25 EST 2001 i586 unknown
on AMD K6, VIA Technologies VT 82C586, Compaq Presario XL119.
Following C program
#include <stdio.h>
#include <sys/time.h>
#include <unistd.h>
#include <time.h>
#define ABS(x) (x < 0 ? -x : x)
#define TIME_T struct timeval
#define TIME_DIFF_T long
#define GET_TIME(x) gettimeofday(&x, NULL)
#define TIME_DIFF(x1, x2) ((x2.tv_sec - x1.tv_sec)*1000000 + (x2.tv_usec -
x1.tv_usec))
int main(int argc, char** argv)
{
TIME_T t1, t2;
TIME_DIFF_T d;

GET_TIME(t2);
while (1) {
GET_TIME(t1);
d = TIME_DIFF(t2, t1);
if (d > 500000 || d < 0) {
fprintf(stderr, "Leap found: %ld msec\n", d);
return 0;
}
t2 = t1;
}
return 1;

gives following result on box in question
root@******:# ./clo
Leap found: -1687 msec
and prints nothing on all other my boxes.
This gives me bunch of troubles with occasional hang ups and I found nothing
in kernel archives at
http://www.uwsg.indiana.edu/hypermail/linux/kernel/index.html
just some notes about smth like this for SMP boxes with ntp. Is this issue
known, and how can I fix it?

Thanks.


_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:22    [W:0.085 / U:3.840 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site