Tuning aha1540 driver (ISC 2.2)

[Heiko Blume]

howardl at wb3ffv.ampr.org ( WB3FFV) writes:
>Have you tried to use any other settings?  Roy Neese at Adaptec strongly
>recomended setting BUSON=7 and BUSOFF=4.  I would think increasing the 
>BUSON time would be a BIG help.  I have heard of several people using a 
>BUSON of 9 and a BUSOFF of 6, but haven't tried that on my side, as Roy's
>recomendations seem to work great.

i just set BUSON to 9 and BUSOFF to 5. no problems until now (although you
might experience problems with bus speeds below 10MHz)

>Here are the various setting for the DMASPEED:

>0 =	5.0  MBytes/sec
>1 =	6.7  MBytes/sec
>2 =	8.0  MBytes/sec
>3 =	10.0 MBytes/sec
>4 =	5.7  MBytes/sec

hmm. where did you get these values from? the 154[02]A manual is different.
the 1540(without A) manual defines these. (not sure about the last one).

>I placed a Adaptec 1542B controller in a 20mhz machine and have it running
>at an 8mhz (DMASPEED=2) DMA rate, but this is highly system dependant.

true. i set DMASPEED two 2 and the boot failed (hangs at the boot message).
i now run at DMASPEED 1 (how fast *is* that now? i miss Roy Neese....!)

while i'm at it again i'll post some benchmark results produced by
boonie (posted not too long ago):


              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
386/33    100   159 89.5   273 18.4   371 59.9   148 94.2   843 86.9  17.4 15.8

this is on an informtech board, 386/33MHz 32KB cache, 8MB RAM, bus speed 12MHz,
adaptec 1542A, CDC/Imprimis 94181 drive (638MB, 19ms, read-ahead on)
with ISC 2.2 set to BUSON 9, BUSOFF 5, DMASPEED 1. boonie used a 100MB file.

another test i did was writ()ing 100000 1K blocks which does 447 Kb/sec and
read()ing 100000 1K blocks wich does 742 KB/sec.

your mileage will vary !
-- 
Heiko Blume c/o Diakite   blume at scuzzy.mbx.sub.org    FAX   (+49 30) 882 50 65
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