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

From: Lee Revell
Date: Fri May 13 2005 - 18:11:14 EST


On Sat, 2005-05-14 at 00:51 +0200, Pavel Machek wrote:
> 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.

Why do you need to disable interrupts for 100ms to read the battery
status exactly?

Lee

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