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

Trent George soundsampler at
Thu Jul 17 21:00:46 PDT 2003

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
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 ?
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)
I have been experimenting with gigabit ethernet and sustained 100mb/s samba read/write performance, and seem to be making good progress.
also experimenting on huge writeback cache (400mb+) up from 1mb vfs.hirunningspace
seems to help with impressive burst network transfer speed.
Trent George
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.

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