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Date: Fri, 13 Jul 2007 11:03:29 +0100 From: Christoph Hellwig <hch@...radead.org> To: Ravikiran G Thirumalai <kiran@...lex86.org> Cc: Andi Kleen <ak@...e.de>, Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org, "Shai Fultheim (Shai@...lex86.org)" <shai@...lex86.org> Subject: Re: [patch] x86_64: Avoid too many remote cpu references due to /proc/stat On Thu, Jul 12, 2007 at 05:06:16PM -0700, Ravikiran G Thirumalai wrote: > Too many remote cpu references due to /proc/stat. > > On x86_64, with newer kernel versions, kstat_irqs is a bit of a problem. > On every call to kstat_irqs, the process brings in per-cpu data from all > online cpus. Doing this for NR_IRQS, which is now 256 + 32 * NR_CPUS > results in (256+32*63) * 63 remote cpu references on a 64 cpu config. > /proc/stat is parsed by common commands like top, who etc, causing > lots of cacheline transfers > > This statistic seems useless. Other 'big iron' arches disable this. > Can we disable computing/reporting this statistic? This piece of > statistic is not human readable on x86_64 anymore, At which point we might just remove it completely.. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.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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