Messages in this thread | | | Date | Sun, 1 Jul 2007 00:53:01 +0200 (CEST) | From | Krzysztof Oledzki <> | Subject | Re: IRQ handling difference between i386 and x86_64 |
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On Sat, 30 Jun 2007, Arjan van de Ven wrote:
> On Sat, 2007-06-30 at 16:55 +0200, Krzysztof Oledzki wrote: >> Hello, >> >> It seems that IRQ handling is somehow different between i386 and x86_64. >> >> In my Dell PowerEdge 1950 is it possible to enable interrupts spreading >> over all CPUs. This a single CPU, four CORE system (Quad-Core E5335 Xeon) >> so I think that interrupts migration may be useful. Unfortunately, it >> works only with 32-bit kernel. Booting it with x86_64 leads to situation, >> when all interrupts goes only to the first cpu matching a smp_affinity >> mask. > > arguably that is the most efficient behavior... round robin of > interrupts is the worst possible case in terms of performance
Even on dual/quadro core CPUs with shared cache? So why it is possible to enable such behaviuor in BIOS, which works only on i386 BTW. :(
> are you using irqbalance ? (www.irqbalance.org)
Yes, I'm aware about this useful tool, but in some situations (routing for example) it cannot help much as it keeps three cpus idle. :(
Best regards,
Krzysztof Olędzki
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