FreeBSD and poor ata performance

[fandino]

Hello list,

 This is an interesting issue. While I was installing  FreeBSD 5.3BETA7
I wonder about the performance that the new branch will bring to my
computer, and it was a deception how bad FreeBSD performs compared
with Linux on the same hardware (even I repeat the test on different PC
with identical results).

A simple test is create one gibabyte file and later read this file again. To
conduct an impartial test the disk (in UDMA5 mode), was formated in both
operating systems with the native filesystem just to be sure that the
physical position of the file will be the same in both tests.

for linux it took about 23 seconds write the file and 18 read it.

# time dd if=/dev/zero of=aa bs=1024k count=1024
1024+0 records in
1024+0 records out

real    0m23.408s
user    0m0.000s
sys    0m4.470s

# time dd if=aa of=/dev/null bs=1024k
1024+0 records in
1024+0 records out

real    0m18.311s
user    0m0.000s
sys    0m5.850s

and for FreeBSD it took 40 seconds write the file and 42 read it:

# dd if=/dev/zero of=aa bs=1024k count=1024
1024+0 records in
1024+0 records out
1073741824 bytes transferred in 40.143630 secs (26747502 bytes/sec)

# dd if=aa of=/dev/null bs=1024k
1024+0 records in
1024+0 records out
1073741824 bytes transferred in 42.711242 secs (25139560 bytes/sec)

so as you can see linux was two times faster that FreeBSD :-?
I would like to know if anyone knows  if this is normal or
is a bug?

thank you.

dmesg:
 http://lists.freebsd.org/pipermail/freebsd-geom/2004-October/000350.html