Sorry, clarification, at least one major and two minor *aic7xxx* revisions
ago.
> I would prefer to play with the AAA-133
> three port card.
3950U2B and a 64bit PCI bus would be much nicer :)
> > For example, I have two different 3950U2B controllers in my machine
> > right now. Each controller has two separate PCI functions. Each
> > function reports MIN_GNT as 39 and MAX_LAT as 25. Multiply that times
> > 4 and what do you get? Impossible to meet. Why are they so
> > particular, well, each funtion is a separate Ultra2 wide SCSI
> > controller and they operate entirely independantly of each other, and
> > fully in parallel, so the four channels are capable of 320MB/s of data
> > transfer.
>
> Fine, but for how long will you be able to read the disks that the 3950U2B
> are controlling at a sustained rate of 320MB/s?
They are all on a single PCI bus, I'll never be able to get that out of
them. If I had 64 bit PCI busses, then I could, but alas, my machine
doesn't have 64bit PCI slots.
> In an old fashioned PCI
> bus (33Mhz and 32 bits wide) the peak disk transfer rate is something less
> than 133MB/s - can you coax the disks to sustain even half of that?
Yes. Depending on the kernel version and such, I can get some pretty nice
performance figures:
[root@dledford /mnt]# bonnie -s 256
File './Bonnie.2021', size: 268435456
Writing with putc()...done
Rewriting...done
Writing intelligently...done
Reading with getc()...done
Reading intelligently...done
Seeker 1...Seeker 3...Seeker 2...start 'em...done...done...done...
-------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
256 11370 98.9 52781 95.8 16791 83.3 12767 89.5 32351 78.4 513.0
14.0
[root@dledford /mnt]#
I could get better performance if I had faster CPUs in this box....the disks
themselves are capable of more.
--Doug Ledford <dledford@dialnet.net> Opinions expressed are my own, but they should be everybody's.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/