From: Christoph Hellwig <hch@infradead.org>
To: Ravikiran G Thirumalai <kiran@scalex86.org>
Cc: Andi Kleen <ak@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
"Shai Fultheim (Shai@scalex86.org)" <shai@scalex86.org>
Subject: Re: [patch] x86_64: Avoid too many remote cpu references due to /proc/stat
Date: Fri, 13 Jul 2007 11:03:29 +0100 [thread overview]
Message-ID: <20070713100329.GE16304@infradead.org> (raw)
In-Reply-To: <20070713000615.GA11942@localdomain>
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..
prev parent reply other threads:[~2007-07-13 10:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-13 0:06 [patch] x86_64: Avoid too many remote cpu references due to /proc/stat Ravikiran G Thirumalai
2007-07-13 0:09 ` [patch] " Ravikiran G Thirumalai
2007-07-13 2:13 ` [patch] x86_64: " Andrew Morton
2007-07-13 6:50 ` Ravikiran G Thirumalai
2007-07-13 10:03 ` Christoph Hellwig [this message]
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