Odd behaviour on recent boot of 11.1 with timecounters
Gary Palmer
gpalmer at freebsd.org
Wed Jan 3 15:06:24 UTC 2018
On Tue, Jan 02, 2018 at 02:41:37PM -0800, Chris H wrote:
> On Tue, 2 Jan 2018 16:45:26 +0000 "Gary Palmer" <gpalmer at freebsd.org> said
>
> > On Sun, Dec 31, 2017 at 06:47:38PM +0200, Konstantin Belousov wrote:
> > > On Sun, Dec 31, 2017 at 03:49:13PM +0000, Gary Palmer wrote:
> > > > On Sun, Dec 31, 2017 at 04:51:47PM +0200, Konstantin Belousov wrote:
> > > > > On Sun, Dec 31, 2017 at 02:17:08PM +0000, Gary Palmer wrote:
> > > > > >
> > > > > > Hi,
> > > > > >
> > > > > > I recently updated to 11.1-RELEASE-p6 and on the most recent reboot
> > > > > > (after rebuilding all the necessary packages) the clock was running
> > > > > > slow and NTP wouldn't sync. I looked in /var/log/messages and I found
> > > > > > that for some reason, on this latest boot, it got the frequency of
> > > > > > TSC-low wrong.
> > > > > >
> > > > > > Aug 24 04:55:35 my kernel: Timecounter "TSC-low" frequency 1746073190
> > > Hz quality 1000
> > > > > > Aug 26 03:11:38 my kernel: Timecounter "TSC-low" frequency 1746070760
> > > Hz quality 1000
> > > > > > Aug 26 14:12:46 my kernel: Timecounter "TSC-low" frequency 1746075204
> > > Hz quality 1000
> > > > > > Nov 19 16:01:09 my kernel: Timecounter "TSC-low" frequency 1746070746
> > > Hz quality 1000
> > > > > > Dec 27 22:28:00 my kernel: Timecounter "TSC-low" frequency 1746074808
> > > Hz quality 1000
> > > > > > Dec 27 22:51:12 my kernel: Timecounter "TSC-low" frequency 1746071892
> > > Hz quality 1000
> > > > > > Dec 28 12:50:46 my kernel: Timecounter "TSC-low" frequency 1746069704
> > > Hz quality 1000
> > > > > > Dec 28 14:03:52 my kernel: Timecounter "TSC-low" frequency 1937876448
> > > Hz quality 1000
> > > > > >
> > > > > > Until the December reboots the machine was running 10.x. Dec 27 and
> > > later
> > > > > > are part of the process to get up to 11.x.
> > > > > >
> > > > > > Any idea why the TSC-low frequency jumped 191,806,744Hz on the last
> > > > > > measurement?
> > > > > >
> > > > > > I switched to HPET temporarily via sysctl and ntp seems happy. I'm
> > > just
> > > > > > concerned that the problem might recur on later reboots as TSC-low
> > > seems
> > > > > > to be the preferred timecounter.
> > > > >
> > > > > Show first 100 lines of the dmesg from a verbose boot.
> > > > > Also check BIOS settings related to overclocking and powersaving.
> > > > >
> > > >
> > > > Hi Konstantin,
> > > >
> > > > BIOS settings haven't been changed in 4+ years. No overclocking, and
> > > > all powersaving options are at "auto" or "disabled".
> > > >
> > > > The first 100 lines of verbose dmesg didn't seem that interesting so
> > > > I've included up to the end of "Device configuration finished"
> > > >
> > > > Note that this boot didn't have the TSC-low problem, and the boot
> > > > that had it wasn't verbose unfortunately.
> > >
> > > It is really the CPU identification which I wanted to see. You have
> > > IvyBridge, which is known to have good TSC.
> >
> > Ah
> >
> > > Try to obtain verbose dmesg with mis-identified frequency.
> >
> > Tried, and failed after 20+ reboots. I've left
> >
> > boot_verbose=" -v"
> I believe that should read:
>
> boot_verbose="YES"
> but maybe just the occurrence of something makes it a positive.
Looks like you're right. I got confused by this comment in
/boot/defaults/loader.conf
#boot_verbose="" # -v: Causes extra debugging information to be printed
After struggling with forth (which I haven't touched in a long time)
it looks like it just tests for the existence of the variable, but
whent he menu toggles verbose on it sets
boot_verbose=YES
Thanks for the hint
Gary
> >
> > in /boot/loader.conf to catch any boot-time wonkiness and undone it at
> > runtime with
> >
> > debug.bootverbose=0
> >
> > in /etc/sysctl.conf as I found that the snd_hda driver is ... chatty
> > at runtime.
> >
> > Thanks,
> >
> > Gary
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>
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