G'day,

I've had NetBSD on this PowerTower Pro 225 for the longest time, primarily
because Linux on this very same system is about as stable as jello. I'm
not slagging Linux/PPC here; it just never worked for me on this system.

Anyhow, NetBSD does run fine, though I'm concerned with lousy performance
from SCSI HA + HD I installed rather recently. The card is a Tekram
DC390U2W based on the Sym83c895 chip, the drive is a Seagate Cheetah.

The card and drive are detected fine:

siop0 at pci1 dev 13 function 0: Symbios Logic 53c895 (ultra2-wide scsi)
siop0: using on-board RAM
siop0: interrupting at irq 27

sd1 at scsibus2 target 0 lun 0: <SEAGATE, ST318203LW, 0002> SCSI2 0/direct
fixed
sd1: 17366 MB, 9772 cyl, 12 head, 303 sec, 512 bytes/sect x 35566480
sectors
sd1: sync (50.0ns offset 15), 16-bit (40.000MB/s) transfers, tagged
queueing

I was able to label the disk and newfs it without issue. Performance,
however, is another story:

# dd bs=1024k count=128 if=/dev/zero of=alpha.00
128+0 records in
128+0 records out
134217728 bytes transferred in 44.479 secs (3017552 bytes/sec)

# dd bs=1024k if=alpha.00 of=/dev/null
128+0 records in
128+0 records out
134217728 bytes transferred in 42.815 secs (3134829 bytes/sec)

I should be getting much more than this from a 10K RPM SCSI drive on U2W!

Perhaps more of concern is that it seems to spend an inordinate amount of
time in the kernel while transferring data:

CPU states:  0.0% user,  0.0% nice, 99.6% system,  0.4% interrupt,  0.0%
idle
   46.09s real     0.02s user    44.29s system

Any ideas on this performance issue? Could it perhaps be due to the fact
that this driver isn't suitable for use on macppc, or that this card was
intended for use on x86 systems (more or less, it has an x86 BIOS at
least)? I do know this card works fine on x86.

If no possible reasons come to mind, I'll have to take a profiler to the
kernel and see just what's going on.

TIA
Eric

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