Re: PATCH: Allow over-ride of smp_found_cfg with kernel cmd-lineoption.

From: Ingo Molnar
Date: Fri Feb 06 2009 - 14:31:50 EST



* Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote:

> Allow user to keep smp_found_cfg set to 1 even if MADT
> cannot be parsed. This works around funky BIOS on FWA-7304
> (VIA CN700 chipset) system, and possibly other systems as well.
> Without this override, performance drops by around 15% on
> network throughput tests on this system.

The question is, _why_ does network performance drop?

Do you have a before/after pair of /proc/interrupts output
perhaps? Does the layout of IRQs change?

The system is not SMP - so only something about UP-IOAPIC can
be helpful to performance here - or some unknown effect.

Ingo
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