Re: rc5+tip/master: Marking clocksource 'tsc' as unstable because the skew is too large:

[Mike Galbraith]

On Thu, 2016-06-30 at 10:41 +0200, Thomas Gleixner wrote:
> On Thu, 30 Jun 2016, Mike Galbraith wrote:
> 
> > On Wed, 2016-06-29 at 19:16 +0200, Borislav Petkov wrote:
> > 
> > > And here it is again:
> > > 
> > > ...
> > > [   15.720833] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes
> ready
> > > [   32.883077] clocksource: timekeeping watchdog on CPU1: Marking
> clocksource 'tsc' as unstable because the skew is too large:
> > > [   32.896986] clocksource:                       'acpi_pm'
> wd_now: 8e147 wd_last: 531b43 mask: ffffff
> > > [   32.908834] clocksource:                       'tsc' cs_now:
> 385f4b6d1e cs_last: 354328bcea mask: ffffffffffffffff
> > > [   32.922293] clocksource: Switched to clocksource acpi_pm
> > 
> > I met that too when testing, but only on my 8 socket box for
> whatever
> > reason.  Putting tip back on the box and poking a bit while I beat
> up
> > rt kernels elsewhere, cs_nsec: 167001172874 wd_nsec: 0.  (poke++)
> 
> can i get the full data please including tsc frequency?

[    0.000000] tsc: Fast TSC calibration using PIT
[    0.000000] tsc: Detected 2260.928 MHz processor
[   13.205453] tsc: Refined TSC clocksource calibration: 2260.999 MHz
[   13.205457] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x20974a4d8bb, max_idle_ns: 440795246623 ns
[   14.592866] clocksource: Switched to clocksource tsc
[  575.781329] clocksource: timekeeping watchdog on CPU23: Marking clocksource 'tsc' as unstable because the skew is too large:
[  575.998835] clocksource:                       'tsc' cs_now: 1c1effead80 cs_last: 139efdabfa5 mask: ffffffffffffffff

trace_printk() leading to splat (hm, mask).
          <idle>-0     [023] ..s.    25.233237: clocksource_watchdog: cs_nsec: 511311920 wd_nsec: 511311599 delta: 321 wdnow: 362266206  cs->wd_last: 354945155 watchdog->mask: ffffffff
          <idle>-0     [023] ..s.    57.234242: clocksource_watchdog: cs_nsec: 511999944 wd_nsec: 511999396 delta: 548 wdnow: 820447848  cs->wd_last: 813116949 watchdog->mask: ffffffff
          <idle>-0     [023] ..s.   575.781321: clocksource_watchdog: cs_nsec: 258345057292 wd_nsec: 0 delta: 258345057292 wdnow: 3949895484  cs->wd_last: 250865676 watchdog->mask: ffffffff