On Fri, Mar 09, 2012 at 12:29:29PM +0100, Lukas Czerner wrote: > Hi, > > I have created a simple script which creates a bunch of files with > random names in the directory and then performs operation like list, > tar, find, copy and remove. I have run it for ext4, xfs and btrfs with > the 4k size files. And the result is that ext4 pretty much dominates the > create times, tar times and find times. However copy times is a whole > different story unfortunately - is sucks badly. > > Once we cross the mark of 320000 files in the directory (on my system) the > ext4 is becoming significantly worse in copy times. And that is where > the hash tree order in the directory entry really hit in. > > Here is a simple graph: > > http://people.redhat.com/lczerner/files/copy_benchmark.pdf > > Here is a data where you can play with it: > > https://www.google.com/fusiontables/DataSource?snapid=S425803zyTE > > and here is the txt file for convenience: > > http://people.redhat.com/lczerner/files/copy_data.txt > > I have also run the correlation.py from Phillip Susi on directory with > 100000 4k files and indeed the name to block correlation in ext4 is pretty > much random :) > > _ext4_ > Name to inode correlation: 0.50002499975 > Name to block correlation: 0.50002499975 > Inode to block correlation: 0.9999900001 > > _xfs_ > Name to inode correlation: 0.969660303397 > Name to block correlation: 0.969660303397 > Inode to block correlation: 1.0 > > > So there definitely is a huge space for improvements in ext4. Thanks Lukas, this is great data. There is definitely room for btrfs to speed up in the other phases as well. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
