kern/94160: Clock running very fast on SMP RELENG_4

[Richard Wiwatowski]

>Number:         94160
>Category:       kern
>Synopsis:       Clock running very fast on SMP RELENG_4
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Mar 07 08:20:08 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Richard Wiwatowski
>Release:        FreeBSD 4-STABLE
>Organization:
>Environment:
FreeBSD gateway.betalogic.com.au 4.11-STABLE FreeBSD 4.11-STABLE #0: Sun Feb 26 15:35:49 CST 2006     root at gateway.betalogic.com.au:/usr/src/sys/compile/GATEWAY  i386

>Description:
System time on my SMP FreeBSD 4.11-STABLE machine is running about 4 times as fast as it should. I also have two other uni-processor systems running the same version: one keeps time using ntpd with a local stratum 2 time source and all other machines on my internal network synchronise to that one (newton) using timed. Today I noticed this on the 2-processor gateway box:

Mar  7 10:56:24 gateway timed[1879]: slave to newton.betalogic.com.au
Mar  7 10:57:16 gateway timed[1879]: date changed by newton.betalogic.com.au from Tue Mar  7 10:56:2
4 2006
Mar  7 11:00:43 gateway timed[1879]: date changed by newton.betalogic.com.au from Tue Mar  7 11:04:0
9 2006
Mar  7 11:04:43 gateway timed[1879]: date changed by newton.betalogic.com.au from Tue Mar  7 11:08:4
2 2006
Mar  7 11:08:43 gateway timed[1879]: date changed by newton.betalogic.com.au from Tue Mar  7 11:12:4
2 2006
Mar  7 11:12:43 gateway timed[1879]: date changed by newton.betalogic.com.au from Tue Mar  7 11:16:4
2 2006
Mar  7 11:16:43 gateway timed[1879]: date changed by newton.betalogic.com.au from Tue Mar  7 11:20:4
3 2006
Mar  7 11:20:43 gateway timed[1879]: date changed by newton.betalogic.com.au from Tue Mar  7 11:24:4
3 2006
Mar  7 11:24:43 gateway timed[1879]: date changed by newton.betalogic.com.au from Tue Mar  7 11:28:4
2 2006
Mar  7 11:28:43 gateway timed[1879]: date changed by newton.betalogic.com.au from Tue Mar  7 11:32:4
3 2006

Seems like the clock is running so fast that timed can't keep it in synch!!

I update my CVS repo once a week these days on Sundays and re-build the whole system on several machines. This is the relevant list of files updated last Sunday:

U src/etc/MAKEDEV
U src/sbin/sconfig/sconfig.c
U src/share/man/man4/man4.i386/Makefile
U src/share/man/man4/man4.i386/ce.4
? src/sys/compile/GATEWAY
U src/sys/conf/files.i386
U src/sys/conf/files.pc98
U src/sys/conf/majors
U src/sys/dev/ce/ceddk.c
U src/sys/dev/ce/ceddk.h
U src/sys/dev/ce/if_ce.c
U src/sys/dev/ce/ng_ce.h
U src/sys/dev/ce/tau32-ddk.c
U src/sys/dev/ce/tau32-ddk.h
U src/sys/dev/usb/usb.c
U src/sys/i386/conf/LINT
U src/sys/i386/i386/mpapic.c
U src/sys/i386/include/cserial.h
U src/sys/modules/ce/Makefile
U src/sys/nfs/nfs_socket.c

I strongly suspect "src/sys/i386/i386/mpapic.c" that was updated like this:

From: John Baldwin <jhb at FreeBSD.org>
Date: Wed, 1 Mar 2006 16:26:51 +0000 (UTC)
X-FreeBSD-CVS-Branch: RELENG_4
Subject: cvs commit: src/sys/i386/i386 mpapic.c

jhb         2006-03-01 16:26:51 UTC

  FreeBSD src repository

  Modified files:        (Branch: RELENG_4)
    sys/i386/i386        mpapic.c 
  Log:
  Use the fixed delivery mode rather than low priority for I/O APIC
  interrupts since low priority delivery mode can only be used logical
  destinations and 4.x and earlier always use only physical destinations.
  
  Revision  Changes    Path
  1.37.2.8  +3 -3      src/sys/i386/i386/mpapic.c

>How-To-Repeat:

>Fix:
Back out the modification? kernel.old doesn't exhibit this problem.

>Release-Note:
>Audit-Trail:
>Unformatted: