GBDE write performance really sucks

Hi Poul,

I have noticed that GBDE write performance is very low, even on modest 
hardware (3.2 P4 with 1MB cache and 7200 IDE HDD):

$ sudo dd if=/dev/zero of=/dev/ad0e.bde bs=128k
29491200 bytes transferred in 31.959903 secs (922756 bytes/sec)
load: 0.00  cmd: dd 3289 [physwr] 0.00u 0.02s 0% 832k
229+0 records in
228+0 records out
29884416 bytes transferred in 32.376493 secs (923028 bytes/sec)
load: 0.00  cmd: dd 3289 [physwr] 0.00u 0.02s 0% 832k
232+0 records in
231+0 records out
30277632 bytes transferred in 32.800038 secs (923097 bytes/sec)
load: 0.00  cmd: dd 3289 [physwr] 0.00u 0.02s 0% 832k
238+0 records in
237+0 records out
31064064 bytes transferred in 33.637685 secs (923490 bytes/sec)
load: 0.00  cmd: dd 3289 [physwr] 0.00u 0.02s 0% 832k
242+0 records in
241+0 records out
31588352 bytes transferred in 34.204824 secs (923506 bytes/sec)
load: 0.00  cmd: dd 3289 [physwr] 0.00u 0.02s 0% 832k
247+0 records in
246+0 records out
32243712 bytes transferred in 34.898871 secs (923918 bytes/sec)
load: 0.00  cmd: dd 3289 [physwr] 0.00u 0.02s 0% 832k
258+0 records in
257+0 records out
33685504 bytes transferred in 36.440052 secs (924409 bytes/sec)
load: 0.00  cmd: dd 3289 [physwr] 0.00u 0.02s 0% 832k
262+0 records in
261+0 records out
34209792 bytes transferred in 36.990503 secs (924826 bytes/sec)

gstat(8) shows that ad0e.bde is nearly 100% busy. I guess that exsessive 
seeks back and forth are knocking performance down, but are there any 
plans to address this issue? Since practical usefullness of the file 
system that can't even sustain 1MB/s on modest hardware is quiestionable.

Regards,

Maxim