Re: [PATCH] ext4: Group meta-data blocks together.

[Eric Sandeen <sandeen@redhat.com>]

Aneesh Kumar K.V wrote:
> On Thu, May 15, 2008 at 11:14:51AM -0500, Eric Sandeen wrote:
>> Aneesh Kumar K.V wrote:
>>> On Thu, May 15, 2008 at 09:23:59PM +0530, Aneesh Kumar K.V wrote:
>>>> This adds a per inode meta-block prealloc space from which
>>>> meta-data block requests are served. This help in making
>>>> sure meta-data block are closer. This is needed to speedup
>>>> unlink of the file. Any new prealloc space is allocated near
>>>> the goal block specified. The goal block is the last block
>>>> allocated for the file. So we don't keep the data-block and
>>>> meta-data block far apart.
>>>>
>>> The result can be found at
>>>
>>> http://www.radian.org/~kvaneesh/ext4/meta-group/
>> Out of curiosity, do you have graphs similar to
>> http://www.radian.org/~kvaneesh/ext4/meta-group/ext4-noextents-metagroup.png
>>
>> before and after your change?
> 
> http://www.radian.org/~kvaneesh/ext4/meta-group/exp1/

Thanks!

On:
http://www.radian.org/~kvaneesh/ext4/meta-group/exp1/ext4-noextents-withoutpatch-rm.png

it seems interesting; do you know what's going on between ~40s and 100s?

Also:

between:
http://www.radian.org/~kvaneesh/ext4/meta-group/exp1/ext4-noextents-read.png
and
http://www.radian.org/~kvaneesh/ext4/meta-group/exp1/ext4-noextents-withoutpatch-read.png

it looks like about a 10% slowdown on the read....

-Eric