Re: Improving raw network performance [was Apache performance etc.]

Benjamin Herrenschmidt (bh40@calva.net)
Tue, 29 Jun 1999 14:37:08 +0200


On Tue, Jun 29, 1999, Jamie Lokier <lkd@tantalophile.demon.co.uk> wrote:

> You could only do this if the interrupt is not shared. But if your
>> network is normally being hammered then you probably didn't configure
>> your network card to be on the same interrupt as your hard disc.
>
>I don't see the problem with a shared interrupt.
>Can you explain?

I beleive he though about using the kernel to mask/unmask the irq line,
which can cause trouble with shared IRQs. Of course, the solution is to
mask them on-chip.

Note that masking/unmasking wiht the kernel's disable_irq/enable_irq from
within the IRQ handler will not work on some platforms (notably PPC,
except if things change since the last time I hacked in this piece of
code). The problem is that if you mask the irq from within the handler,
it will be unmasked by the kernel when going out of the handler.

-- 
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