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Re: htree 2.4.19-dxdir patch



On Sun, Sep 22, 2002 at 05:54:27PM +0200, Marc-Christian Petersen wrote:
> : without index mount:
>
> root codeman:[/test] # time randfiles foo 100000
> 
> real    32m55.929s
> user    0m1.890s
> sys     32m2.500s
> 
> : with index mount:
> 
> root codeman:[/test] # time randfiles foo 100000
> 
> real    32m53.929s
> user    0m1.690s
> sys     32m0.500s

These times don't look right.  Are you sure you created the filesystem
was using directorying indexing turned on?  With it turned on,
creating 100,000 files should take 10-20 seconds depending on the
speed of your system and hard disks.  

Here's the test script I use for testing directory indexing:

#!/bin/sh
dd if=/dev/zero of=test.img bs=8k count=30000
mke2fs -j -F -b 1024 -g 1024 -N 1200000 test.img 
debugfs -w -R "features dir_index" test.img
debugfs -w -R "ssv def_hash_version tea" test.img
debugfs -w -R "ssv hash_seed random" test.img
mount -t ext3 -o loop test.img /mnt
pushd /mnt
mkdir test test2 test3
cd test
time seq -f "%06.0f" 1 100  | xargs touch
cd ..
cd test2
time seq -f "%06.0f" 1 10000  | xargs touch
cd ..
cd test3
time seq -f "%06.0f" 1 100000  | xargs touch
cd ..
popd
umount /mnt

(You can comment out the 'dd' line after the first time you run the
test to speeds things up a bit.)

On my system, creating the files in the test3 directory takes 11.408
seconds real time, with 6.221 seconds of system time with the
directory indexing.  If I comment out the debugfs line which activates
the "dir_index" filesystem feature flag, then directory indexing is
turned off, and the script takes 38:07 minutes of real time, with
38:05 of it being system time.

Your times are consistent with directory indexing not being turned on.

						- Ted

P.S.  These tests were with 2.5.36 using the patches available at
	
	http://thunk.org/tytso/linux/ext3-dxdir

There are also patches against 2.4.19 available.  There are a few
minor bugs still with the 2.5.36 patches, but they will be fixed in
the patches against 2.5.38 which I should have ready shortly.





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