stable-8 regression: time stands still

[Jeremy Chadwick]

On Wed, Mar 03, 2010 at 09:09:56AM +0100, Ruben de Groot wrote:
> > > I'm going to get this kern.timecounter sysctl from the system booted with a 7.x livecd 
> > > this evening. But really, I think this is a regression. Even if this system is the only
> > > one known to be affected (which I sincerely doubt).
> > 
> > You can force a timecounter choice by setting it in /boot/loader.conf.
> > I would recommend choosing ACPI-safe on your system to see if that
> > improves things:
> > 
> > kern.timecounter.hardware=ACPI-safe
> 
> Thanks, that solved my issue. Allthough for correctness I must add that this line
> must be put in /etc/sysctl.conf; it does nothing in loader.conf.
> Also the sysctl can be run in multiuser and immediately fixed the problem.

Ah, I thought it was a loader tunable, not a sysctl tunable.  My
apologies!  Yes, sysctl.conf is the correct place for this.

> One question remains: why did this suddenly become a problem in FreeBSD 8 and not
> in FreeBSD 7.

That would be a question for the people who decided upon the timecounter
priorities in FreeBSD, since they're hard-coded (meaning: why HPET is
chosen above ACPI-safe).  This may have changed between RELENG_7 and
RELENG_8; I simply don't know.  It would be easy to verify on your
system of course (just boot a FreeBSD 7 LiveCD and provide the output
from sysctl kern.timecounter).

-- 
| Jeremy Chadwick                                   jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |