Date: Wed, 3 Mar 2010 11:16:51 +0000 From: Tom Evans <tevans.uk@googlemail.com> To: Jeremy Chadwick <freebsd@jdc.parodius.com> Cc: freebsd-stable@freebsd.org, Ruben de Groot <mail25@bzerk.org>, "C. P. Ghost" <cpghost@cordula.ws> Subject: Re: stable-8 regression: time stands still Message-ID: <2e027be01003030316v719ae418o35ec64ab33aae9df@mail.gmail.com> In-Reply-To: <20100303110901.GB51588@icarus.home.lan> References: <20100301203450.GA99170@ei.bzerk.org> <20100301211441.GB99170@ei.bzerk.org> <op.u8wrcqh18527sy@212-123-145-58.ip.telfort.nl> <20100302084347.GA4719@ei.bzerk.org> <d74eb87c1003020309g53248f4ao685d09d0f940f87c@mail.gmail.com> <20100302171227.GA26933@ei.bzerk.org> <20100302173632.GA29314@icarus.home.lan> <20100303080956.GA32493@ei.bzerk.org> <20100303110901.GB51588@icarus.home.lan>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, Mar 3, 2010 at 11:09 AM, Jeremy Chadwick <freebsd@jdc.parodius.com> wrote: > 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=3DACPI-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 proble= m. > > Ah, I thought it was a loader tunable, not a sysctl tunable. =C2=A0My > apologies! =C2=A0Yes, 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). =C2=A0This may have changed between RELENG_7 and > RELENG_8; I simply don't know. =C2=A0It would be easy to verify on your > system of course (just boot a FreeBSD 7 LiveCD and provide the output > from sysctl kern.timecounter). > Another possibility could be that RELENG_7 was finding ACPI-fast, which is rated above HPET. I'm not sure why some machines get ACPI-fast and some get ACPI-safe - I think ACPI-fast is tested at boot up, and if the measurements are not consistent, it disables ACPI-fast and uses ACPI-safe instead, which is then ignored when HPET is available. Cheers Tom
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?2e027be01003030316v719ae418o35ec64ab33aae9df>