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)? >>> >>> >>> >> Johnny, >> >> 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 >> actually" >> >> To answer the previous question I do have the HW clock set to utc, >> Everything is stock from initial install of the package. >> >> Brian. > 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 > machines. > > 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 > http://lists.centos.org/mailman/listinfo/centos 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. Nataraj -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20110415/7c0bf8c7/attachment-0005.html>