Re: Maildir parsing optimization for ext3/Linux 2.6
Florian Weimer <fw@xxxxxxxxxxxxx>:
> Linux 2.6 adds hashed directory support to ext3. As a result, readdir()
> returns directory entries in a pretty wild order. Opening files in
> this order results in enormous seek overhead. This overhead can be
> reduced if the files are sorted by inode number first.
>
> Without the patch below, mutt needs 200 seconds to open a maildir folder
> with 18,500 messages which does not reside in the dentry/page cache. If
> the patch is applied, less than 15 seconds are required. If the folder
> is in cache, 3.1 vs. 3.3 seconds are needed.
Sounds good, but could you reassure us that the patch has or should
have no ill effect on other filing systems, such as ext2, reiserfs and
xfs?
I would guess that reiserfs is quite a popular choice for people who
use big maildir folders as reiserfs is supposed to be good with small
files, so perhaps reiserfs should be tested.
Some people who have tested and compared say xfs is the best, but it
doesn't seem to be very widely used compared with reiserfs and ext3.