Debian package performance on XFS, btrfs, ext3, ext4

I did 4 clean installations of debian 6 and measured time of installing some average virtual package. FS options are default.

time apt-get install build-essential

I got very strange results (min:sec, less is faster):

XFS:   3:12
btrfs: 2:45
ext3:  0:30
ext4:  0:50

What is wrong with XFS and btrfs? 6 times slower than ext3? Am I doing something wrong?

Upd (some details):

All LVM volumes are local to VM and are on idle RAID. CDROM image is local and the same, Internet connection is stable and it factors max 10-15 seconds. All the visible slowdowns are after downloads: XFS and btrfs guests think over 1 second every Unpacking. Low-level caching is disabled. Host node is idle every installation, no active guests but the one.

Solution 1:

Which kernel version do you use? If I read this correct, something still 2.6.X, right, so XFS@2009-2010?

XFS has been known to have a serious bottleneck in its log writing mechanism. This is something which has finally been solved in kernel version 3.3 once and for all and the solution is enabled there by default.

So you should update your system's kernel and then you should be on the safe side.