From: Eric Sandeen <sandeen@redhat.com>
To: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andrew Morton <akpm@linux-foundation.org>,
ext4 development <linux-ext4@vger.kernel.org>,
Jan Kara <jack@suse.cz>
Subject: Re: [PATCH 1/2] ext2: speed up file creates by optimizing rec_len functions
Date: Wed, 08 Dec 2010 20:13:46 -0600 [thread overview]
Message-ID: <4D003B5A.5060807@redhat.com> (raw)
In-Reply-To: <F51EB2BF-8C99-4E2F-943E-E795A0F4DF7F@dilger.ca>
On 12/8/10 3:44 PM, Andreas Dilger wrote:
> On 2010-12-08, at 14:07, Eric Sandeen wrote:
>> On 12/08/2010 01:01 PM, Andreas Dilger wrote:
>>> I think an important factor here is that this is being tested on
>>> a ramdisk, and is likely CPU bound, so any CPU reduction will
>>> directly be measured as a performance improvement. Probably
>>> oprofile is in order to see where other major CPU users are.
>>
>> Yep, I ran oprofile.
>>
>> samples % app name symbol name 1140046
>> 41.8702 ext2.ko ext2_find_entry 1052117 38.6408
>> ext2.ko ext2_add_link 98424 3.6148 vmlinux
>> native_safe_halt 40461 1.4860 vmlinux
>> wait_on_page_read 29084 1.0682 vmlinux
>> find_get_page
>>
>> pretty slammed on those 2 ext2 functions! I think it's pretty
>> overwhelmed by the linear search.
>
> Can you test ext4 with nojournal mode, but with dir_index enabled? I
> suspect that testing ext2 for directory performance is pointless.
Oh, I agree. I just had a report of a regression in a certain distro,
which is frowned upon... :) I'm positive ext4 nojournal would beat the
pants off it due to dir_index.
> My personal threshold for ext2 directories was 10k files before I
> considered it a lost cause, and all of your tests are with 10k+ files
> per directory.
Agreed, it's not very realistic but then it was a simple fix too.
Still took time though...
> Just another log on the fire beneath getting rid of ext2 (and
> eventually ext3) in favour of ext4, IMHO. I'd be surprised if there
> are many benchmarks that ext2 can beat ext4 in nojournal mode, if
> allowed to enable "reversible" format changes like dir_index,
> uninit_bg, etc.
Hey, I wouldn't complain.
-Eric
> Cheers, Andreas
>
>
>
>
>
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next prev parent reply other threads:[~2010-12-09 2:14 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-07 17:47 [PATCH 0/2] ext2, ext3: speed up file create workloads Eric Sandeen
2010-12-07 17:51 ` [PATCH 1/2] ext2: speed up file creates by optimizing rec_len functions Eric Sandeen
2010-12-07 21:07 ` Andrew Morton
2010-12-07 21:22 ` Eric Sandeen
2010-12-07 21:33 ` Andrew Morton
2010-12-07 21:36 ` Eric Sandeen
2010-12-08 19:01 ` Andreas Dilger
2010-12-08 21:07 ` Eric Sandeen
2010-12-08 21:44 ` Andreas Dilger
2010-12-09 1:06 ` Ric Wheeler
2010-12-10 17:55 ` Ted Ts'o
2010-12-10 18:05 ` Ric Wheeler
2010-12-10 23:40 ` Andreas Dilger
2010-12-11 0:24 ` Eric Sandeen
2010-12-09 2:13 ` Eric Sandeen [this message]
2010-12-07 17:55 ` [PATCH 2/2] ext3: " Eric Sandeen
2011-01-06 14:47 ` [PATCH 0/2] ext2, ext3: speed up file create workloads Jan Kara
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