time issues and ZFS

[Adrian Chadd]

Hi,

Try experimenting with kern.eventtimer.periodic and kern.eventtimer.idletick.

If this fixes it for you, please file a PR with all the relevant details.

Thanks!




Adrian


On 21 January 2013 03:33, Daniel Braniss <danny at cs.huji.ac.il> wrote:
> After many trials (and errors), here are some facts:
>
> host: DELL PowerEdge R710, 16GB,
>  mfi0: <Dell PERC H700 Integrated>
>  mfid0: 14305280MB (29297213440 sectors) RAID volume 'r5' is optimal
>  mfi1: <Dell PERC 6>
>  mfid1: 12393472MB (25381830656 sectors) RAID volume 'Virtual Disk 0' is
> optimal
>
> we have NO problems with FreeBSD-8.3-STABLE, but with 9.1-STABLE, the real-time
> clock slows down when doing some zfs stuff like send|receive, typing 'date'
> when less that 1000s went by seems to crorrect the problem,
> ntpd kicks in and on track again.
>
> I have a cron job just logging date every 5 minutes, and the loghost sees:
>
> |-- local time on loghost             | time on problematic host
> Jan 20 19:56:19 store-02.cs.huji.ac.il Jan 20 19:56:19 danny: Sun Jan 20
> 19:56:19 IST 2013       -- ok
> Jan 20 20:15:00 store-02.cs.huji.ac.il Jan 20 20:15:00 danny: Sun Jan 20
> 20:15:00 IST 2013       -- ok
> Jan 20 21:30:00 store-02.cs.huji.ac.il Jan 20 20:21:06 danny: Sun Jan 20
> 20:21:06 IST 2013       -- off by 1:09
> Jan 20 21:33:53 store-02.cs.huji.ac.il Jan 20 20:25:00 danny: Sun Jan 20
> 20:25:00 IST 2013       -- off by 1:08
> Jan 20 21:38:54 store-02.cs.huji.ac.il Jan 20 20:30:00 danny: Sun Jan 20
> 20:30:00 IST 2013       -- off by 1:09
> ...
> Jan 20 22:03:54 store-02.cs.huji.ac.il Jan 20 20:55:00 danny: Sun Jan 20
> 20:55:00 IST 2013       -- diff is now constant
> ..
> Jan 20 22:04:13 store-02.cs.huji.ac.il Jan 20 20:55:19 ntpd[1848]: time
> correction of 4134 seconds exceeds sanity limit (1000); set clock manually to
> the correct UTC time.
> ...
> Jan 20 22:58:53 store-02.cs.huji.ac.il Jan 20 21:50:00 danny: Sun Jan 20
> 21:50:00 IST 2013
>
>
> strangely, when running 8.3, ACPI-fast is chosen:
>         kern.timecounter.choice: TSC(-100) HPET(900) ACPI-fast(1000) i8254(0)
> dummy(-1000000)
> but with 9.1 TSC-low gets chosen:
>         kern.timecounter.choice: TSC-low(1000) ACPI-fast(900) HPET(950) i8254(0)
> dummy(-1000000)
>
> so I did sysctl kern.timecounter.hardware=ACPI-fast, but the same happens -
> unless it can't be changed after boot.
>
> I realy need help here!
>
> thanks,
>         danny
>
>
>
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