From: Mingming <cmm@us.ibm.com>
Subject: Re: Test results for ext4
Date: Fri, 30 May 2008 10:48:32 -0700
Message-ID: <1212169712.8596.76.camel@BVR-FS.beaverton.ibm.com>
References: <48402253.8040407@bull.net>
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Cc: ext4 development <linux-ext4@vger.kernel.org>,
	"Jose R. Santos" <jrs@us.ibm.com>
To: Valerie Clement <valerie.clement@bull.net>
In-Reply-To: <48402253.8040407@bull.net>
Sender: linux-ext4-owner@vger.kernel.org


On Fri, 2008-05-30 at 17:50 +0200, Valerie Clement wrote:
> Hi all,
>=20

Hi Valerie,

> Since a couple of weeks, I did batches of tests to have some performa=
nce
> numbers for the new ext4 features like uninit_groups, flex_bg or
> journal_checksum on a 5TB filesystem.
> I tried to test allmost all combinations of mkfs and mount options, b=
ut
> I put only a subset of them in the result tables, the most significan=
t
> for me.
>=20

Thanks, that's very helpful.

> I had started to do these tests on a kernel 2.6.26-rc1, but I'd got s=
everal
> hangs and crashes occuring randomly outside ext4, sometimes in the sl=
ab
> code or in the scsi driver eg., and which were not reproductible.
> Since 2.6.26-rc2, no crash or hang occur with ext4 on my system.
>=20
> The first results and the test description are available here:
> http://www.bullopensource.org/ext4/20080530/ffsb-write-2.6.26-rc2.htm=
l

Interesting nomballoc is faster than default (with mballoc) about 3%,
but the fragmentation is much better.

> http://www.bullopensource.org/ext4/20080530/ffsb-readwrite-2.6.26-rc2=
=2Ehtml
>=20


> I will complete them in the next days.
>=20
> In the first batch of tests, I compare the I/O throughput to create
> 1-GB files on disk in different configurations. The CPU usage is also
> given to show mainly how the delayed allocation feature reduces it.
> The average number of extents per file shows the impact of the
> multiblock allocator and the flex_bg grouping on the file fragmentati=
on.
> At last, the fsck time shows how the uninit_groups feature reduces th=
e
> e2fsck duration.
>=20
Don't know if Jose has any suggestions, I am curious what's the impact
of flex bg alone on fsck perf?

> In the second batch of tests, the results show improvements in transa=
ctions
> -per-second throughput when doing small files writes, reads and creat=
es
> when using the flex_bg grouping.
> The same ffsb test on an XFS filesystem hangs, I will try to have tra=
ces.
>=20

> If you are interested in other tests, please let me know.
>=20
I also wondering if you get a chance to test larger inode (>256 bytes)
with uninit group and flex bg?=20

>    Val=C3=A9rie
>=20
>=20
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