FAQ Search Today's Posts Mark Forums Read
» Video Reviews

» Linux Archive

Linux-archive is a website aiming to archive linux email lists and to make them easily accessible for linux users/developers.


» Sponsor

» Partners

» Sponsor

Go Back   Linux Archive > CentOS > CentOS

 
 
LinkBack Thread Tools
 
Old 04-13-2011, 11:16 PM
"Denniston, Todd A CIV NAVSURFWARCENDIV Crane"
 
Default CentOs 5.6 and Time Sync

> -----Original Message-----
> From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On
> Behalf Of Peter Brady
> Sent: Wednesday, April 13, 2011 18:39
> To: CentOS mailing list
> Subject: Re: [CentOS] CentOs 5.6 and Time Sync
>
> On 14/04/11 7:42 AM, Mailing List wrote:
> > remote refid st t when poll reach delay
> offset
> > jitter
> >
>
================================================== =====================
> =======
> >
> > bindcat.fhsu.ed 132.163.4.101 2 u 1015 1024 377 49.987 -
> 15082.
> > 6919.88
> > 216.45.57.38 108.71.253.18 2 u 998 1024 377 83.112 -
> 15139.
> > 6900.14
> > javanese.kjsl.c 69.36.224.15 2 u 1 1024 377 109.083 -
> 29233.
> > 7285.83
> > *LOCAL(0) .LOCL. 10 l 13 64 377 0.000
> 0.000
> > 0.001
>
> <snip>
>
> Glad you've got a fix but you should keep an eye on it.
>
> If you look at the output for ntpq you have three stratum 2 servers
> which differ by ~15s from both you and each other. Stratum 2 servers
> should be a lot closer than 15s given that they are only one link
> removed from some form of atomic clock.
>

I think you may be comparing a couple of rotting apples to one that is
just now ripening.
when offset
1015 15082
998 15139
1 29233

i.e., the samples that are 17 seconds apart in the taking are .057S
apart in value, and trending longer.




_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-13-2011, 11:45 PM
Peter Brady
 
Default CentOs 5.6 and Time Sync

On 14/04/11 9:16 AM, Denniston, Todd A CIV NAVSURFWARCENDIV Crane wrote:
> I think you may be comparing a couple of rotting apples to one that is
> just now ripening.
> when offset
> 1015 15082
> 998 15139
> 1 29233
>
> i.e., the samples that are 17 seconds apart in the taking are .057S
> apart in value, and trending longer.

Ah, fair enough.

-pete

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-14-2011, 07:27 AM
allan
 
Default CentOs 5.6 and Time Sync

Mailing List wrote:
> On 4/13/2011 3:35 PM, Cal Webster wrote:
>>
>> I'm running the same kernel and ntp versions and I'm having no problems
>> at all on ntp servers or clients.
>>
>> If my previous suggestions didn't help maybe you could share contents of
>> the following files and output of some commands so the list can see what
>> you've got.
>>
>> /etc/ntp.conf
>> /etc/ntp/ntpservers
>> /etc/ntp/step-tickers
>> /var/lib/ntp/drift
>>
>>
>> grep ntpd /var/log/messages*
>> (please remove repeated messages for clarity)
>>
>> Most recent entries in /var/log/ntpd.log
>>
>> SELinux could also be playing a role.
>>
>> Are you running SELinux enabled, permissive, or disabled?
>> What mode was it running before it stopped working?
>> Are there any possibly related "avc" messages in /var/log/messages
>> or /var/audit/audit.log?
>>
>> ./Cal
>>
> /etc/ntp;
>
> restrict default kod nomodify notrap nopeer noquery
> restrict -6 default kod nomodify notrap nopeer noquery
> restrict 127.0.0.1
> restrict -6 ::1
> server 0.centos.pool.ntp.org
> server 1.centos.pool.ntp.org
> server 2.centos.pool.ntp.org
> server 127.127.1.0 # local clock
> fudge 127.127.1.0 stratum 10
> driftfile /var/lib/ntp/drift
> keys /etc/ntp/keys
>
> There is no /etc/ntp/ntpservers
>
> /etc/ntp/step-tickers is an empty file.
>
> /var/lib/ntp/drift;
> -65.219
>
> I have no /var/log/ntpd.log
>
> /varlog/messages; This is the log using stock updated kernel.
>
> Apr 12 03:32:35 Server ntpd[2797]: synchronized to LOCAL(0), stratum 10
> Apr 12 03:33:36 Server ntpd[2797]: synchronized to 173.9.142.98, stratum 2
> Apr 12 15:51:56 Server ntpd[2797]: time reset +43208.248852 s
> Apr 12 15:51:56 Server ntpd[2797]: kernel time sync enabled 0001
> Apr 12 15:56:03 Server ntpd[2797]: synchronized to LOCAL(0), stratum 10
> Apr 12 15:56:26 Server ntpd[2797]: synchronized to 169.229.70.183,
> stratum 3
> Apr 12 16:00:22 Server ntpd[2797]: synchronized to 173.9.142.98, stratum 2
> Apr 12 16:16:59 Server ntpd[2797]: synchronized to 169.229.70.183,
> stratum 2
> Apr 12 16:16:57 Server ntpd[2797]: time reset -1.830305 s
> Apr 12 16:20:27 Server ntpd[2797]: synchronized to LOCAL(0), stratum 10
> Apr 12 16:22:35 Server ntpd[2797]: synchronized to 169.229.70.183,
> stratum 2
> Apr 12 16:28:01 Server ntpd[2797]: synchronized to 173.9.142.98, stratum 2
> Apr 12 16:32:29 Server ntpd[2797]: synchronized to 169.229.70.183,
> stratum 3
> Apr 12 16:36:36 Server ntpd[2797]: synchronized to 173.9.142.98, stratum 2
> Apr 12 16:40:05 Server ntpd[2797]: synchronized to 169.229.70.183,
> stratum 3
> Apr 12 16:41:57 Server ntpd[2797]: synchronized to LOCAL(0), stratum 10
> Apr 12 16:42:09 Server ntpd[2797]: synchronized to 173.9.142.98, stratum 2
> Apr 12 16:47:28 Server ntpd[2797]: synchronized to LOCAL(0), stratum 10
> Apr 12 16:48:28 Server ntpd[2797]: synchronized to 169.229.70.183,
> stratum 3
> Apr 12 16:51:44 Server ntpd[2797]: synchronized to 173.9.142.98, stratum 2
> Apr 12 16:53:52 Server ntpd[2797]: synchronized to 173.193.227.67,
> stratum 4
> Apr 12 16:58:06 Server ntpd[2797]: synchronized to 169.229.70.183,
> stratum 3
> Apr 12 17:00:18 Server ntpd[2797]: synchronized to LOCAL(0), stratum 10
> Apr 12 17:04:31 Server ntpd[2797]: synchronized to 169.229.70.183,
> stratum 3
> Apr 12 17:06:44 Server ntpd[2797]: synchronized to LOCAL(0), stratum 10
> Apr 12 19:54:46 Server ntpd[2797]: ntpd exiting on signal 15
> Apr 13 03:01:24 Server ntpd[2409]: ntpd 4.2.2p1@1.1570-o Sat Dec 19
> 00:56:13 UTC 2009 (1)
> Apr 13 03:01:24 Server ntpd[2410]: precision = 1.000 usec
> Apr 13 03:01:24 Server ntpd[2410]: Listening on interface wildcard,
> 0.0.0.0#123 Disabled
> Apr 13 03:01:24 Server ntpd[2410]: Listening on interface wildcard,
> ::#123 Disabled
> Apr 13 03:01:24 Server ntpd[2410]: Listening on interface lo, ::1#123
> Enabled
> Apr 13 03:01:24 Server ntpd[2410]: Listening on interface eth0,
> fe80::218:8bff:fe80:67db#123 Enabled
> Apr 13 03:01:24 Server ntpd[2410]: Listening on interface lo,
> 127.0.0.1#123 Enabled
> Apr 13 03:01:24 Server ntpd[2410]: Listening on interface eth0,
> 192.168.2.1#123 Enabled
> Apr 13 03:01:24 Server ntpd[2410]: kernel time sync status 0040
> Apr 13 03:01:30 Server ntpd[2410]: frequency initialized 0.000 PPM from
> /var/lib/ntp/drift
> Apr 13 07:04:44 Server ntpd[2410]: synchronized to LOCAL(0), stratum 10
> Apr 13 07:04:44 Server ntpd[2410]: kernel time sync enabled 0001
> Apr 13 07:11:09 Server ntpd[2410]: synchronized to 208.75.88.4, stratum 2
> Apr 13 07:17:34 Server ntpd[2410]: synchronized to 64.6.144.6, stratum 2
> Apr 13 07:42:59 Server ntpd[2410]: time reset -27.586767 s
> Apr 13 07:46:35 Server ntpd[2410]: synchronized to LOCAL(0), stratum 10
> Apr 13 07:47:38 Server ntpd[2410]: synchronized to 199.249.224.123,
> stratum 2
> Apr 13 07:51:53 Server ntpd[2410]: synchronized to 64.6.144.6, stratum 2
> Apr 13 09:27:19 Server ntpd[2410]: ntpd exiting on signal 15
> Apr 13 09:27:19 Server ntpd[6743]: ntpd 4.2.2p1@1.1570-o Sat Dec 19
> 00:56:13 UTC 2009 (1)
>
> Selinux is disabled, and just a note also. This is a stock install of
> of ntp. I never had to do any fudging with it cause it just worked up
> until the update.
>
> I also have no /var/log/audit/audit.log.
>
> tia.
>
> Brian
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos

43208 seconds is 8 seconds from 12 hours. Could this be an AM/PM issue? or a tz issue? what timezone have you set?
ntp uses UTC time. Is your machine hw clock set for UTC?

Just a few thoughts.

Peace,
Allan



_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-14-2011, 10:47 AM
Johnny Hughes
 
Default CentOs 5.6 and Time Sync

On 04/13/2011 10:31 AM, Mailing List wrote:
> On 4/13/2011 7:35 AM, Mailing List wrote:
>> Hi,
>>
>> I have upgraded my Dell C151 to the latest 5.6. I have always used
>> ntp to sync this machine and then the rest of the machines in the
>> network would sync from it. Since the update I cannot keep the right
>> time on the machine. This is with / without ntp. I have attempted
>> various scenario's with no luck. I am now trying the old kernel now as
>> I type this out. If anyone else has any links or ideas that I should
>> check out It would be greatly appreciated.
>>
>> Just a quick note about my setup. I do not use any gui. As
>> mentioned I have not had any issues with this machine and it's time
>> until I upgrade.
>>
>> AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
>> 3gb of ram.
>>
>> TIA.
>>
>> Brian.
>
> Just to follow up, I had switched to the old kernel before the 5.6
> upgrade, and at this time my clock is working flawlessly.
>
> kernel v. 2.6.18-194.32.1.el5 Works as it should...
> kernel v. 2.6.18-238.5.1.el5 I cannot get my clock accurate.
>
> If there is anything I can do to help solve this IE: information or
> test. please let me know.At this point I will just make the old kernel
> default boot until there is a kernel update where which I will try again.

Is it really true that the time is working perfectly with one of the
other kernels (the older ones)?

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-14-2011, 11:23 AM
Mailing List
 
Default CentOs 5.6 and Time Sync

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.



_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-14-2011, 11:28 AM
"Simon Matter"
 
Default CentOs 5.6 and Time Sync

> 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.

Did you check dmesg which timer is being used (I think it can also be seen
somewhere in /proc but I don't remember). If it's hpet, you could try to
disable it. That was for i686: 'hpet=disable' and for x86_64: 'nohpet',
don't know how it is with current kernels.

Simon

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-15-2011, 12:34 AM
Cal Webster
 
Default CentOs 5.6 and Time Sync

On Thu, 2011-04-14 at 13:28 +0200, Simon Matter 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.
>
> Did you check dmesg which timer is being used (I think it can also be seen
> somewhere in /proc but I don't remember). If it's hpet, you could try to
> disable it. That was for i686: 'hpet=disable' and for x86_64: 'nohpet',
> don't know how it is with current kernels.
>
> Simon

Forgive me if I've missed a later post but it looked like this thread
was stagnant...

You may have something here Simon. I was thinking about your suggestion
that it could be a timer issue. I'm wondering if the default clocksource
or some related timer kernel parameter has been changed between
2.6.18-194.17.4.el5 (5.5) and 2.6.18-238.5.1.el5 (5.6).

Timer related issues could very well account for this large,
inconsistent NTP drift as well as Florin Andrei's "bizarre" tar, scp,
and NTP issues in the "[CentOS] bizarre system slowness" thread. System
interrupts are based on the clocksource chosen by (or configured in) the
kernel. Any service or facility that uses these interrupts could be
experiencing problems.

Can anyone on the list confirm whether or not timer related kernel
parameters have changed in 5.6? I don't have source handy and I'm going
out the door in minutes.

Reading up on kernel timer options, I came across these articles.

# Discusses mis-detected timer frequency
9.2.4.2.7. Kernel 2.6 Mis-Detecting CPU TSC Frequency
http://support.ntp.org/bin/view/Support/KnownOsIssues#Section_9.2.4.2.7.

# Describes ntpd instability from some time sources
# Includes data and graphs from detailed study
http://www.ep.ph.bham.ac.uk/general/support/adjtimex.html


I checked clock sources on a few systems under my control to see what
came up. None are experiencing this problem. The CentOS and FC12
machines are isolated from the Internet while the FC14 laptop connects.
My sample CentOS 5.5 & 5.6 systems are different hardware platforms. The
5.6 box doesn't have the hpet timer available so it may just not be
susceptible to this problem. I'll be updating the 5.5 sample to 5.6
tomorrow which does have hpet available so I should know something more
then.

# Used these to get available and current clocksource:
cat /sys/devices/system/clocksource/clocksource0/available_clocksource
cat /sys/devices/system/clocksource/clocksource0/current_clocksource

# CentOS 5.5:
Available: acpi_pm jiffies hpet tsc pit
Current: tsc

# CentOS 5.6:
Available: acpi_pm jiffies tsc pit
Current: tsc

# Fedora 12:
Available: tsc hpet acpi_pm
Current: tsc

# Fedora 14: Using hpet
Available: hpet acpi_pm
Current: hpet








_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-15-2011, 11:08 AM
Johnny Hughes
 
Default CentOs 5.6 and Time Sync

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@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-15-2011, 03:42 PM
Nataraj
 
Default CentOs 5.6 and Time Sync

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@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





_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 04-15-2011, 08:58 PM
Mailing List
 
Default CentOs 5.6 and Time Sync

On 4/15/2011 7:08 AM, Johnny Hughes wrote:


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?



Johnny,

Sorry about the wrong system id number here is what it is.

Dell Inspiron C521
Bios Version 1.1.11 (08/07/2007)

It is not a VM, it is a regular install. I have not made any
changes to the kernel options. It has been fine with a stock install so
I never had any need to tweek it.


Thank you.
Brian



_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 

Thread Tools




All times are GMT. The time now is 04:50 AM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.
Copyright 2007 - 2008, www.linux-archive.org