From: Mark Fasheh <mark.fasheh@oracle.com>
To: Andi Kleen <ak@suse.de>
Cc: Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com
Subject: [Ocfs2-devel] Ocfs2 performance bugs of doom
Date: Mon, 6 Mar 2006 20:58:35 -0800 [thread overview]
Message-ID: <20060307045835.GF27280@ca-server1.us.oracle.com> (raw)
In-Reply-To: <p733bhvgc7f.fsf@verdi.suse.de>
On Tue, Mar 07, 2006 at 04:34:12AM +0100, Andi Kleen wrote:
> Did you actually do some statistics how long the hash chains are?
> Just increasing hash tables blindly has other bad side effects, like
> increasing cache misses.
Yep, the gory details are at:
http://oss.oracle.com/~mfasheh/lock_distribution.csv
This measure was taken about 18,000 locks into a kernel untar. The only
change was that I switched things to only hash the last 18 characters of
lock resource names.
In short things aren't so bad that a larger hash table wouldn't help. We've
definitely got some peaks however. Our in-house laboratory of mathematicians
(read: Bill Irwin) is checking out methods by which we can smooth things out
a bit more :)
--Mark
--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh at oracle.com
WARNING: multiple messages have this Message-ID (diff)
From: Mark Fasheh <mark.fasheh@oracle.com>
To: Andi Kleen <ak@suse.de>
Cc: Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com
Subject: Re: Ocfs2 performance bugs of doom
Date: Mon, 6 Mar 2006 20:58:35 -0800 [thread overview]
Message-ID: <20060307045835.GF27280@ca-server1.us.oracle.com> (raw)
In-Reply-To: <p733bhvgc7f.fsf@verdi.suse.de>
On Tue, Mar 07, 2006 at 04:34:12AM +0100, Andi Kleen wrote:
> Did you actually do some statistics how long the hash chains are?
> Just increasing hash tables blindly has other bad side effects, like
> increasing cache misses.
Yep, the gory details are at:
http://oss.oracle.com/~mfasheh/lock_distribution.csv
This measure was taken about 18,000 locks into a kernel untar. The only
change was that I switched things to only hash the last 18 characters of
lock resource names.
In short things aren't so bad that a larger hash table wouldn't help. We've
definitely got some peaks however. Our in-house laboratory of mathematicians
(read: Bill Irwin) is checking out methods by which we can smooth things out
a bit more :)
--Mark
--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com
next prev parent reply other threads:[~2006-03-07 4:58 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-03 22:27 [Ocfs2-devel] Ocfs2 performance bugs of doom Daniel Phillips
2006-03-03 22:27 ` Daniel Phillips
2006-03-04 0:53 ` [Ocfs2-devel] " Mark Fasheh
2006-03-04 0:53 ` Mark Fasheh
2006-03-04 3:42 ` [Ocfs2-devel] " Daniel Phillips
2006-03-04 3:42 ` Daniel Phillips
2006-03-04 7:36 ` Andrew Morton
2006-03-04 7:37 ` [Ocfs2-devel] " Andrew Morton
2006-03-05 19:22 ` Mark Fasheh
2006-03-05 19:22 ` Mark Fasheh
2006-03-06 1:28 ` [Ocfs2-devel] " Daniel Phillips
2006-03-06 1:28 ` Daniel Phillips
2006-03-06 2:58 ` [Ocfs2-devel] " Mark Fasheh
2006-03-06 2:58 ` Mark Fasheh
2006-03-06 4:59 ` Daniel Phillips
2006-03-06 4:59 ` Daniel Phillips
2006-03-06 19:51 ` Mark Fasheh
2006-03-06 19:51 ` Mark Fasheh
2006-03-07 3:34 ` Andi Kleen
2006-03-07 3:34 ` Andi Kleen
2006-03-07 4:58 ` Mark Fasheh [this message]
2006-03-07 4:58 ` Mark Fasheh
2006-03-07 6:56 ` [Ocfs2-devel] " Daniel Phillips
2006-03-07 6:56 ` Daniel Phillips
2006-03-09 6:26 ` Daniel Phillips
2006-03-09 6:26 ` Daniel Phillips
2006-03-09 7:26 ` Nick Piggin
2006-03-09 7:26 ` Nick Piggin
2006-03-09 7:43 ` Nick Piggin
2006-03-09 7:43 ` Nick Piggin
2006-03-09 4:19 ` Andi Kleen
2006-03-09 4:19 ` Andi Kleen
2006-03-09 12:30 ` Nick Piggin
2006-03-09 12:30 ` Nick Piggin
2006-03-10 5:14 ` Nick Piggin
2006-03-10 5:14 ` Nick Piggin
2006-03-10 0:21 ` [Ocfs2-devel] Ocfs2 performance Mark Fasheh
2006-03-10 0:21 ` Mark Fasheh
2006-03-10 1:14 ` Bernd Eckenfels
2006-03-10 7:10 ` Joel Becker
2006-03-10 7:10 ` Joel Becker
2006-03-11 1:09 ` Mark Fasheh
2006-03-11 1:09 ` Mark Fasheh
2006-03-11 1:57 ` Bernd Eckenfels
2006-03-11 1:57 ` Bernd Eckenfels
2006-03-10 11:17 ` Daniel Phillips
2006-03-10 11:17 ` Daniel Phillips
2006-03-10 18:23 ` Zach Brown
2006-03-10 18:23 ` Zach Brown
2006-03-10 21:13 ` Daniel Phillips
2006-03-10 21:13 ` Daniel Phillips
2006-03-10 21:13 ` Daniel Phillips
2006-03-10 21:13 ` Daniel Phillips
2006-03-10 2:33 ` [Ocfs2-devel] Ocfs2 performance bugs of doom J. Bruce Fields
2006-03-10 2:33 ` J. Bruce Fields
2006-03-10 10:27 ` Daniel Phillips
2006-03-10 10:27 ` Daniel Phillips
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