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Subject: Re: [RFC] New locking primitive for 2.5
From: Robert Love <rml@tech9.net>
To: Alexander Viro <viro@math.psu.edu>
Cc: Linus Torvalds <torvalds@transmeta.com>, Andrew Morton <akpm@zip.com.au>,
        Martin Wirth <Martin.Wirth@dlr.de>, linux-kernel@vger.kernel.org,
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Date: 08 Feb 2002 14:36:26 -0500
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On Fri, 2002-02-08 at 14:21, Alexander Viro wrote:

> Had anyone actually seen lseek() vs. lseek() contention prior to the
> switch to ->i_sem-based variant?

Yes, I did, even on my 2-way.

Additionally, when I posted the remove-bkl-llseek patch, someone from
SGI noted that on a 24-processor NUMA IA-64 machine, _50%_ of machine
time was spent spinning on the BKL in llseek-intense operations.

The bkl is not held for a long time, but it is acquired often, and there
are definitely workloads that show a big hit with the BKL in there.

	Robert Love

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