Re: [announce] [patch] limiting IRQ load, irq-rewrite-2.4.11-B5

Ingo Molnar
2001-10-03T18:25:48Z

On Wed, 3 Oct 2001, Linus Torvalds wrote:

> Now test it again with the disk interrupt being shared with the
> network card.
>
> Doesn't happen? It sure does. [...]

yes, disk IRQs might be delayed in that case. Without this mechanizm there
is a lockup.

> Which is why I like the NAPI approach. If somebody overloads my
> network card, my USB camera doesn't stop working.

i agree that NAPI is a better approach. And IRQ overload does not happen
on cards that have hardware-based irq mitigation support already. (and i
should note that those cards will likely perform even faster with NAPI.)

> I don't disagree with your patch as a last resort when all else fails,
> but I _do_ disagree with it as a network load limiter.

okay - i removed those parts already (kpolld) in today's patch. (It
initially was an experiment to prove that this is the only problem we are
facing under such loads.)

Ingo