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Date: Thu, 7 Jun 2001 14:02:15 +0200 (CEST)
From: thomas.pornin@ens.fr
Reply-To: thomas.pornin@ens.fr
To: FreeBSD-gnats-submit@freebsd.org
Cc: alpha@freebsd.org
Subject: Time jitter under load on FreeBSD 4.3 alpha
X-Send-Pr-Version: 3.2

>Number:         27933
>Category:       alpha
>Synopsis:       Time jitter under load on FreeBSD 4.3 alpha
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-alpha
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jun 07 05:10:01 PDT 2001
>Closed-Date:    Tue May 24 02:10:56 GMT 2005
>Last-Modified:  Tue May 24 02:10:56 GMT 2005
>Originator:     Thomas Pornin
>Release:        FreeBSD 4.3-RELEASE alpha
>Organization:
Ecole Normale Superieure
>Environment:

The machine is an AXPpci (NoName) board, with a 166 MHz 21066 Alpha cpu,
32 MB of ram, 256 KB of cache. Disks are scsi, using the onboard 53c810
controller; driver is ncr.

>Description:

Under high load, the clock drifts: it slows down. It looses about
20 minutes during a complete "make buildworld" (which takes about 22
hours on that machine).

I installed ntpd; when the machine is idle, everything is fine, but
when there is some load (cpu, disk, memory, I do not know which one is
relevant), ntpd issues messages such as "time reset -1.319533 s" every
20 minutes or so.

(I actually observed that effect with FreeBSD 4.0 to 4.2 on a Multia,
which is supposed to be similar to the AXPpci board)

>How-To-Repeat:

Deactivate ntpd, setup date and clock, perform a make buildworld, type
"date" afterwards, observe the date shift.

>Fix:

None included. I can perform a bit of testing, just ask.
>Release-Note:
>Audit-Trail:

From: Sten Spans <sten@blinkenlights.nl>
To: bug-followup@FreeBSD.org, thomas.pornin@ens.fr
Cc:  
Subject: Re: alpha/27933: Time jitter under load on FreeBSD 4.3 alpha
Date: Mon, 23 May 2005 22:51:59 +0200 (CEST)

 Could you verify that the problem still exists on 5.4-RELEASE ?
 Also freebsd now has the hw.timecounter.hardware option, could
 you try changing that to one of the other choices ?
 
 -- 
 Sten Spans
 
 "There is a crack in everything, that's how the light gets in."
 Leonard Cohen - Anthem
State-Changed-From-To: open->feedback 
State-Changed-By: marcel 
State-Changed-When: Tue May 24 02:04:47 GMT 2005 
State-Changed-Why:  
Change state to reflect (re)verification request. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=27933 
State-Changed-From-To: feedback->closed 
State-Changed-By: marcel 
State-Changed-When: Tue May 24 02:09:36 GMT 2005 
State-Changed-Why:  
Mail bounces. Since this applies to 4.x close the PR. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=27933 
>Unformatted:
