Re: [regression 4.14rc] 74def747bcd0 (genirq: Restrict effective affinity to interrupts actually using it)

[Yanko Kaneti <yaneti@declera.com>]

On Tue, 2017-09-19 at 16:33 +0100, Marc Zyngier wrote:
> On 19/09/17 16:12, Yanko Kaneti wrote:
> > Hello, 
> > 
> > Fedora rawhide config here. 
> > AMD FX-8370E
> > 
> > Bisected a problem to:
> > 74def747bcd0 (genirq: Restrict effective affinity to interrupts actually using it) 
> > 
> > It seems to be causing stalls, short lived or long lived lockups very shortly after boot. 
> > Everything becomes jerky.
> > 
> > The only visible in the log indication is something like :
> > ....
> > [   59.802129] clocksource: timekeeping watchdog on CPU3: Marking clocksource 'tsc' as unstable because the skew is too large:
> > [   59.802134] clocksource:                       'hpet' wd_now: 3326e7aa wd_last: 329956f8 mask: ffffffff
> > [   59.802137] clocksource:                       'tsc' cs_now: 423662bc6f cs_last: 41dfc91650 mask: ffffffffffffffff
> > [   59.802140] tsc: Marking TSC unstable due to clocksource watchdog
> > [   59.802158] TSC found unstable after boot, most likely due to broken BIOS. Use 'tsc=unstable'.
> > [   59.802161] sched_clock: Marking unstable (59802142067, 15510)<-(59920871789, -118714277)
> > [   60.015604] clocksource: Switched to clocksource hpet
> > [   89.015994] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 209.660 msecs
> > [   89.016003] perf: interrupt took too long (1638003 > 2500), lowering kernel.perf_event_max_sample_rate to 1000
> > ....
> > 
> > Just reverting that commit on top of linus mainline cures all the symptoms
> 
> Interesting. Do you still get HPET interrupts?

Sorry, I might need some basic help here (i.e where do I count them...)

After the watchdog switches the clocksource to hpet the system is still
 somewhat alive, so I'll guess some clock is still ticking....

-Yanko