On 04/15/2011 04:08 AM, Johnny Hughes wrote:
On 04/14/2011 06:23 AM, Mailing List wrote:
On 4/14/2011 6:47 AM, Johnny Hughes wrote:
Is it really true that the time is working perfectly with one of the
other kernels (the older ones)?


Yes, As long as I run the older 5.5 kernel my time is perfect. All
clients can get from this machine with no issues. As soon as I run new
kernel, or Plus kernel for that matter. The time goes downhill. "Uphill

To answer the previous question I do have the HW clock set to utc,
Everything is stock from initial install of the package.

I do not see anything from Dell that is a model C151.

I also do not see anything in the RH bugzilla that is problematic for
older AMD processors and the clock, unless running KVM type virtual

Is this a VM or regular install?

If this a real machine, do you have the latest BIOS from Dell?

Do you have any special kernel options in grub?

CentOS mailing list
CentOS at centos.org
It also occured to me to ask if this was running in a VM, but it sounded
like it was running on actual hardware. I once had a vmware VM in
which I had similar misbehavior of the clock. Eventually I discovered
that the following simple program when run inside the VM would return
immediately instead of delaying for 10 seconds as it should.

#include <stdio.h>
/* #include <sys/select.h> */
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

int main() {
fd_set set;
struct timeval timeout;
int filedes = STDIN_FILENO;

FD_ZERO (&set);
FD_SET (filedes, &set);

timeout.tv_sec = 10;
timeout.tv_usec = 0;

select(FD_SETSIZE, &set, NULL, NULL, &timeout);


I then found out that the ISP had set the host OS for my VM to Ubuntu
when I was running CentOS 5 in the VM. The cause was that VMware
assumed a tickless kernel for Ubuntu, but not for CentOS 5 and there
were optimizations in the VM emulation that counted on VMware knowing
what timekeeping options where set in the kernel.


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.centos.org/pipermail/centos/attachments/20110415/7c0bf8c7/attachment.html

Search Discussions

Discussion Posts


Follow ups

Related Discussions

Discussion Navigation
viewthread | post
posts ‹ prev | 26 of 37 | next ›
Discussion Overview
groupcentos @
postedApr 13, '11 at 7:35a
activeMay 12, '11 at 1:06p



site design / logo © 2023 Grokbase