time issues and ZFS

[Daniel Braniss]

> Hi,
> 
> Try experimenting with kern.eventtimer.periodic and kern.eventtimer.idletick.
> 
can you give/point to some info about this?

btw, I just noticed that on this hardware I get:
9.1-STABLE:

> vmstat -i
interrupt                          total       rate
irq3: uart1                          931          0
irq4: uart0                            5          0
irq19: ehci0                        1331          0
irq20: hpet0 uhci3               1687937       1163
irq21: uhci2 ehci1                    29          0
irq23: atapci0                        48          0
irq256: bce0                       52270         36
irq260: mfi0                       14690         10
irq261: mfi1                        3088          2
Total                            1760329       1213

no cpu timer, instead irq20: hpet0 uhci3,
and when 8.3-STABLE:
> vmstat -i
interrupt                          total       rate
irq3: uart1                         1048          0
irq4: uart0                            5          0
irq19: ehci0                      280451          1
irq21: uhci2 ehci1                    29          0
irq23: atapci0                        52          0
cpu0:timer                     313544623       1125
irq256: bce0                    30791673        110
irq260: mfi0                     1372186          4
cpu1:timer                       1294093          4
...

total                          384382790       1380

is this OK?


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

> 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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