[1272] in linux-scsi channel archive
AHA 1542 driver performance questions
daemon@ATHENA.MIT.EDU (David A Willmore)
Fri Jan 17 14:41:18 1997
Date: Fri, 17 Jan 1997 13:36:32 -0600
From: David A Willmore <willmore@cig.mot.com>
To: linux-scsi@vger.rutgers.edu
Cc: willmore@cig.mot.com
I have recently aquired an aha1542A SCSI card. It works with the aha1542
driver just fine, except that the performance isn't what I was expecting. I
had been hoping that it would be a very good SCSI-I performer and that doesn't
seem to be the case. I have an array of five drives hanging off of it.
They're Connor CP30100 (117 meg SCSI-I drives w/sync, disconnect, etc.) which
can do >1M/sec each. I was hoping that they could do quite well as a raid
array. From running five 'dd's at the same time, I don't think that my
assumption is correct. I get about 1.8 M/sec total from the five drives.
My questions: (1) is this what I should expect? (2) does this driver do sync
transfer on the SCSI bus and, if so, can I get it to tell me what speed it's
doing it at? (3) does it do disconnect/reconnect?
The interupt load from this thing is beautiful. With all five drives running,
it wasn't servicing more than 30-40 interupts/sec. That's impressive.
Am I unreasonable to expect more out of this card? Am I unreasonable to expect
more out of this driver? Should I consider improving the driver? Is that even
possible?
Any information is greatly appreciated. FYI, testing was done with a 4.5" SCSI
bus with passive termination at both ends. I was running linux 2.0.18 with the
version of the aha1542 driver that is native to that patch level.
Thanks in advance for any information or comments that you would like to make.
Cheers,
David
P.S. yeah, yeah, I would rather run a few 53c810 or 825 (or better) cards, but
I've got a 486DX4/120 with a VLB bus, so that's not yet an option. As soon as
I get one, you can *bet* I'll stuff it with 53c8xx cards and relegate this card
to feeding tape drives.
