promise sx4000 card & tx4000 results over 170mb/s sustained read

[Soeren Schmidt]

It seems Trent George wrote:
> Hi Soren,
>  
> I wanted to congratulate you on fantastic results in performance on a tx4000 card.
>  
> I have a dual amd mb with 66mhz support slot. 4 western digital drives (180gb each)
>  
> I have clocked sustained 176mb/s read from this raid0 array and 120+mb/s write
>  
> writes seemed cpu bound ? (50% idle from second processor)
> reads 56% idle (first process close to maxed out)
>  
> there were several tricks to getting this performance, custom kernel compile
>  
> 1/ MAXPHYS=256k
> 2/ MAXBSIZE=256k
> 3/ atacontrol create RAID0 128 /dev/ad4 /dev/ad6 /dev/ad8 /dev/ad10
> 4/ newfs -U bs=262144 /dev/ar0  
>  
> this allowed 64kb stripe size to use 4 drives on each "block" parallel reading
>  
> i used iostat to monitor processor and transfer rate using following commands
>  
> dd of=test.dat if=/dev/zero bs=64k count=20000
> dd if=test.dat of=/dev/null bs=64k

Wooo! not bad at all :) 
I'd suspect performance like that, but dont have the HW to test it so this
is most welcomed!!

> Question #2
>  
> I purchased a sx4000 card in the hope to increase speed :-)
> I noticed that PDC20621 is not in ata-chipset.c yet
> The card is not recognised on boot ether.
>  
> Is there anything I can do or provide to help you add support for this card ?

I do have the sx4000 in the works (thanks to Promise who has provided docs
and HW to make this happen)..

> Question #3
>  
> Is there any plans to support intel SATA raid support on ICH5R (i865/i875) for boot up (sort of like promise and highpoint)

Uhm, well, for this to happen I need to figure out the where they store the
RAID config (my guess is on disk somewhere), then reverseengineer the
contents and write routines for ata-raid.c to r/w the config blocks.
This can be quite a bit of work and needs alot of trial error experimentation
which needs someone with access to the HW and a fair amount of determination.

(just FYI I've just ripped Adaptecs RAID config apart on their new SATA
controller :) )

> PS I don't know if you remember but I sent an amd system to you a long time ago to help add support for highpoint chipsets, I appreciate all your great work.

I do remember!! that system actually was my main workstation for a long
time (until the capacitors gave up but that problem has hit alot of
Abit boards from that time period), so it has contributed to FreeBSD in
more than one sense, thanks!!

-Søren