Re: kern/44227: 5.99.25 misdects CPU frequency

[Thomas Klausner <wiz%NetBSD.org@localhost>]

The following reply was made to PR kern/44227; it has been noted by GNATS.

From: Thomas Klausner <wiz%NetBSD.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/44227: 5.99.25 misdects CPU frequency
Date: Mon, 13 Dec 2010 01:11:57 +0100

 On Sun, Dec 12, 2010 at 11:10:01PM +0000, lacombar%gmail.com@localhost wrote:
 > >Synopsis:       5.99.25 misdects CPU frequency
 
 When booting with a few Xeon W3520, 2660MHz, the cpu line reported by
 NetBSD switches between
 cpu0 at mainbus0 apid 0: Intel 686-class, 2672MHz, id 0x106a5
 and
 cpu0 at mainbus0 apid 0: Intel 686-class, 3207MHz, id 0x106a5
 
 This also causes
 -timecounter: Timecounter "TSC" frequency 2672865880 Hz quality 3000
 +timecounter: Timecounter "TSC" frequency 3207398120 Hz quality 3000
 
 For this reason I've switched the timecounter to avoid the time
 drifting problem:
 # grep timecounter /etc/sysctl.conf
 kern.timecounter.hardware=hpet0
 
 Then I at least don't see any effects of this weirdness.
 
 I've seen this behaviour for a long time now (at least in 5.99.15,
 5.99.22, 5.99.23, 5.99.24, 5.99.36, 5.99.39) also with different
 numbers (e.g. 3741MHz). I didn't notice it in the last month or so,
 but there were less reboots than usual. Sometimes reboots change the
 MHz.
  Thomas