Re: linux interrupt handling problem

Roman Zippel (zippel@fh-brandenburg.de)
Wed, 10 Nov 1999 11:30:53 +0100 (MET)


Hi,

On Tue, 9 Nov 1999, Alan Cox wrote:

> However if you want to do 64Kbit sync off a MacII or 38,400 async you have
> to accept that the 85x30 series devices are a real time problem.
>
> You don't want to pollute the main code with irq levels but you do want to
> draw a line and say "below this IPL is linux" "above this IPL its party
> time". You define all the Linux locking to work by raising to the given IPL
> not the top IPL, and you play _very_ carefully in your 'real time' IRQ
> handlers.

That's a problem I would like to address later, since it's a perfomance
only problem, where the sti() stuff is also a portability problem.
Anyway, I'm preparing some stuff to address this, but that's the more
complex change, but I hope to get a better overall perfomance out of
this, as there are more perfomance problems with some linux interrupt
handler (especially almost all block devices).

bye, Roman

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