From: "Jörn Engel" <joern@logfs.org>
To: Christoph Lameter <clameter@sgi.com>
Cc: Andy Whitcroft <apw@shadowen.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Mel Gorman <mel@skynet.ie>, David Chinner <dgc@sgi.com>
Subject: Re: [RFC 00/26] Slab defragmentation V5
Date: Thu, 6 Sep 2007 22:34:12 +0200 [thread overview]
Message-ID: <20070906203412.GB27657@lazybastard.org> (raw)
In-Reply-To: <20070901014107.719506437@sgi.com>
On Fri, 31 August 2007 18:41:07 -0700, Christoph Lameter wrote:
>
> The trouble with this patchset is that it is difficult to validate.
> Activities are only performed when special load situations are encountered.
> Are there any tests that could give meaningful information about
> the effectiveness of these measures? I have run various tests here
> creating and deleting files and building kernels under low memory situations
> to trigger these reclaim mechanisms but how does one measure their
> effectiveness?
One could play with updatedb followed by a memhog. How much time passes
and how many slab objects have to be freed before the memhog has
allocated N% of physical memory? Both numbers are relevant. The first
indicates how quickly pages are reclaimed from slab caches, while the
second show how many objects remain cached for future lookups. Updatedb
aside, caching objects is done for solid performance reasons.
Creating a qemu image with little memory and a huge directory hierarchy
filled with 0-byte files may be a nice test system. Unless you beat me
to it I'll try to set it up once logfs is in merge-worthy shape.
Jörn
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prev parent reply other threads:[~2007-09-06 20:38 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-01 1:41 [RFC 00/26] Slab defragmentation V5 Christoph Lameter
2007-09-01 1:41 ` [RFC 01/26] SLUB: Extend slabinfo to support -D and -C options Christoph Lameter
2007-09-01 1:41 ` [RFC 02/26] SLUB: Move count_partial() Christoph Lameter
2007-09-01 1:41 ` [RFC 03/26] SLUB: Rename NUMA defrag_ratio to remote_node_defrag_ratio Christoph Lameter
2007-09-01 1:41 ` [RFC 04/26] SLUB: Add defrag_ratio field and sysfs support Christoph Lameter
2007-09-01 1:41 ` [RFC 05/26] SLUB: Replace ctor field with ops field in /sys/slab/:0000008 /sys/slab/:0000016 /sys/slab/:0000024 /sys/slab/:0000032 /sys/slab/:0000040 /sys/slab/:0000048 /sys/slab/:0000056 /sys/slab/:0000064 /sys/slab/:0000072 /sys/slab/:0000080 /sys/slab/:0000088 /sys/slab/:0000096 /sys/slab/:0000104 /sys/slab/:0000128 /sys/slab/:0000144 /sys/slab/:0000184 /sys/slab/:0000192 /sys/slab/:0000216 /sys/slab/:0000256 /sys/slab/:0000344 /sys/slab/:0000384 /sys/slab/:0000448 /sys/slab/:0000512 /sys/slab/:0000768 /sys/slab/:0000920 /sys/slab/:0001024 /sys/slab/:0001152 /sys/slab/:0001344 /sys/slab/:0001536 /sys/slab/:0002048 /sys/slab/:0003072 /sys/slab/:0004096 /sys/slab/:a-0000056 /sys/slab/:a-0000080 /sys/slab/:a-0000128 /sys/slab/Acpi-Namespace /sys/slab/Acpi-Operand /sys/slab/Acpi-Pa rse /sys/slab/Acpi-ParseExt /sys/slab/Acpi-State /sys/slab/RAW /sys/slab/TCP /sys/slab/UDP /sys/sl Christoph Lameter
2007-09-01 1:41 ` [RFC 06/26] SLUB: Add get() and kick() methods Christoph Lameter
2007-09-01 1:41 ` [RFC 07/26] SLUB: Sort slab cache list and establish maximum objects for defrag slabs Christoph Lameter
2007-09-01 1:41 ` [RFC 08/26] SLUB: Consolidate add_partial and add_partial_tail to one function Christoph Lameter
2007-09-01 1:41 ` [RFC 09/26] SLUB: Slab defrag core Christoph Lameter
2007-09-01 1:41 ` [RFC 10/26] SLUB: Trigger defragmentation from memory reclaim Christoph Lameter
2007-09-01 1:41 ` [RFC 11/26] VM: Allow get_page_unless_zero on compound pages Christoph Lameter
2007-09-01 1:41 ` [RFC 12/26] SLUB: Slab reclaim through Lumpy reclaim Christoph Lameter
2007-09-01 1:41 ` [RFC 13/26] SLUB: Add SlabReclaimable() to avoid repeated reclaim attempts Christoph Lameter
2007-09-19 15:08 ` Rik van Riel
2007-09-19 18:00 ` Christoph Lameter
2007-09-01 1:41 ` [RFC 14/26] SLUB: __GFP_MOVABLE and SLAB_TEMPORARY support Christoph Lameter
2007-09-01 2:04 ` KAMEZAWA Hiroyuki
2007-09-01 2:07 ` Christoph Lameter
2007-09-01 1:41 ` [RFC 15/26] bufferhead: Revert constructor removal Christoph Lameter
2007-09-01 1:41 ` [RFC 16/26] Buffer heads: Support slab defrag Christoph Lameter
2007-09-01 1:41 ` [RFC 17/26] inodes: Support generic defragmentation Christoph Lameter
2007-09-01 1:41 ` [RFC 18/26] FS: ExtX filesystem defrag Christoph Lameter
2007-09-01 9:48 ` Jeff Garzik
2007-09-02 11:37 ` Christoph Lameter
2007-09-01 1:41 ` [RFC 19/26] FS: XFS slab defragmentation Christoph Lameter
2007-09-01 1:41 ` [RFC 20/26] FS: Proc filesystem support for slab defrag Christoph Lameter
2007-09-01 1:41 ` [RFC 21/26] FS: Slab defrag: Reiserfs support Christoph Lameter
2007-09-01 1:41 ` [RFC 22/26] FS: Socket inode defragmentation Christoph Lameter
2007-09-01 1:41 ` [RFC 23/26] dentries: Extract common code to remove dentry from lru Christoph Lameter
2007-09-01 1:41 ` [RFC 24/26] dentries: Add constructor Christoph Lameter
2007-09-01 1:41 ` [RFC 25/26] dentries: dentry defragmentation Christoph Lameter
2007-09-01 1:41 ` [RFC 26/26] SLUB: Add debugging for slab defrag Christoph Lameter
2007-09-06 20:34 ` Jörn Engel [this message]
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