Re: [PATCH V2] kernel/watchdog: fix spurious hard lockups

[Don Zickus]

On Tue, Jun 27, 2017 at 04:48:22PM -0700, Andi Kleen wrote:
> > I haven't heard back any test result yet.
> > 
> > The above patch looks good to me.
> 
> This needs performance testing.  It may slow down performance or latency sensitive workloads.

More motivation to work through the issues with the proposed real fix? :-)

> 
> > Which workaround do you prefer, the above one or the one checking timestamp?
> 
> I prefer the earlier patch, it has far less risk of performance issues.

But now you are slowing down the nmi_watchdog so much that the
watchdog_thresh hold becomes meaningless, no? (granted the turbo-mode blows
it out of the water too)  So now folks who depend on the 10/5/1/whatever second
reliability lose that.  I think that might be unfair too.

The hrtimer increase maintains that and just adds a few more
interrupts/second.

Cheers,
Don