Re: [discuss] Re: [PATCH] adjust x86-64 watchdog tick calculation

[Pavel Machek]

Hi!

> > > > > > Because it kills machine when interrupt latency gets too high?
> > > > > > Like reading battery status using i2c...
> > > > > 
> > > > > That's a bug in the I2C reader then. Don't shot the messenger for bad news.
> > > > 
> > > > Disagreed.
> > > > 
> > > > Linux is not real time OS. Perhaps some real-time constraints "may not
> > > > spend > 100msec with interrupts disabled" would be healthy
> > >              ^^^^
> > > You mean "microseconds", right?  100ms will be perceived by the user as,
> > > well, their machine freezing for 100ms...
> > 
> > I did mean miliseconds. IIRC current watchdog is at one second and it
> > still triggers even in cases when operation just takes too long.
> 
> I thought there was an understanding that 1 ms would be the target for
> desktop responsiveness.  So yes, disabling interrupts for more than 1ms
> is considered a bug.

I do not think so.

In may be "worth fixing", but no, that does not mean you should stick
"if ints_disabled > 1msec panic()" into code. That would make most
systems unusable.

Think pio-only disks, for example. Think serial console.
									Pavel
-- 
Boycott Kodak -- for their patent abuse against Java.
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