Re: Promise SX8 performance issues and CARM_MAX_Q

[Bernard Blackham <bernard@blackham.com.au>]

On Thu, Mar 24, 2005 at 11:09:17PM -0500, Jeff Garzik wrote:
> The driver was developed on a pre-production board, so its entirely 
> possible Promise fixed this issue.
> 
> The driver should be solid for _at least_ CARM_MAX_Q==31, presuming that 
> the firmware doesn't choke.

Stressing this SX8 card broke with CARM_MAX_Q anything higher than
16. Tests included simultaneous iozones, bonnie++'s, fsx, badblocks,
and mkfs'ing, on 4 ports. Setting CARM_MAX_Q to 17 or above
resulted in errors such as:

Buffer I/O error on device sx80_0p1, logical block 108828
lost page write due to I/O error on sx80_0p1
end_request: I/O error, dev sx80_2, sector 389167

It's been thrashing away with various tests most of today with
CARM_MAX_Q = 16, and it hasn't missed a beat.

Thanks must go to Matt Johnston who actually did all the work of
giving the card and drives a hard time.

Bernard.

-- 
 Bernard Blackham <bernard at blackham dot com dot au>