From: Mark Tinguely <tinguely@sgi.com>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH] [RFC] xfs: lookaside cache for xfs_buf_find
Date: Mon, 09 Sep 2013 10:17:24 -0500 [thread overview]
Message-ID: <522DE684.4000903@sgi.com> (raw)
In-Reply-To: <1378690396-15792-1-git-send-email-david@fromorbit.com>
On 09/08/13 20:33, Dave Chinner wrote:
> From: Dave Chinner<dchinner@redhat.com>
>
> CPU overhead of buffer lookups dominate most metadata intensive
> workloads. The thing is, most such workloads are hitting a
> relatively small number of buffers repeatedly, and so caching
> recently hit buffers is a good idea.
>
> Add a hashed lookaside buffer that records the recent buffer
> lookup successes and is searched first before doing a rb-tree
> lookup. If we get a hit, we avoid the expensive rbtree lookup and
> greatly reduce the overhead of the lookup. If we get a cache miss,
> then we've added an extra CPU cacheline miss into the lookup.
Interesting. The last allocated xfs_buf is placed into the hash.
Might be interesting to know the hit-miss ratio on a real workload.
--Mark.
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next prev parent reply other threads:[~2013-09-09 15:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-09 1:33 [PATCH] [RFC] xfs: lookaside cache for xfs_buf_find Dave Chinner
2013-09-09 15:17 ` Mark Tinguely [this message]
2013-09-09 15:39 ` Dave Chinner
2013-09-18 21:48 ` Mark Tinguely
2013-09-18 23:24 ` Dave Chinner
2013-09-19 13:23 ` Mark Tinguely
2013-09-23 14:17 ` Mark Tinguely
2013-09-23 21:25 ` Michael L. Semon
2013-09-24 0:48 ` Dave Chinner
2013-09-24 17:41 ` Mark Tinguely
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