Messages in this thread | | | Date | Wed, 21 May 2003 22:12:42 -0400 (EDT) | From | Zwane Mwaikambo <> | Subject | Re: userspace irq balancer |
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On Wed, 21 May 2003, William Lee Irwin III wrote:
> This is not the case. Interrupt arbitration for sane things generally > balances interrupt load automatically in-hardware. AIUI the TPR was > intended to enable the hardware to do such a thing for xAPIC. Linux > doesn't use the TPR now, which results in decisions made by the > hardware on xAPIC -based SMP systems that are highly detrimental to > performance.
Well using the APIC arbitration round robin thing isn't all that smart either unless you use the TPR, so TPR would be a win everywhere.
> IMHO Linux on Pentium IV should use the TPR in conjunction with _very_ > simplistic interrupt load accounting by default and all more > sophisticated logic should be punted straight to userspace as an > administrative API. > > i.e. frob the fscking TPR as recommended by the APIC docs every once in > a while by default, punt anything (and everything) fancier up to > userspace, and get the code that doesn't even understand what the fsck > DESTMOD means the Hell out of the kernel and the Hell away from my > IO-APIC RTE's.
Word... This is all rather tired, if we have a working irq affinity user accessible interface this can all go away, so how about we just work towards that means, and then remove kirqd when everyone is happy (personally i like Arjan's/RH9 userland irqbalance).
Zwane -- function.linuxpower.ca - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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