performance issues: linux aic7xxx, 29160, Radion IFT-7200

[Justin T. Gibbs]

>Hello again,
>
>Adjusting the tagged command queuing value hasn't improved performance
>as measured with hdparm -t.
>
>Working with the 2.4.18 kernel, aic7xxx version 6.2.5 and queue depths
>ranging from 0-32 I have consistently gotten results in the range of
>13-16 MB/s using hdparm -t. With the old 5.2.4 driver hdparm -t gives
>results of 47 MB/s.

I wonder if for some reason we have disconnection disabled?  I get much
better performance than that talking to a plain old 10K RPM disk.  Can
you go into aic7xxx.c, search for ahc->user_discenable and print out the
contents of that variable?

Both drivers negotiate to the same values?

>Is there something else I can do to try to get better performance with
>the new driver?

If I understood why the performance was bad, I'd tell you. 8-)
Any chance you can rent a SCSI bus analyzer for a day and capture
some traces?

>You made a distinction between sequential and non-sequential workloads.

If you have multple mp3's being written or read from at the same time,
this will be a non-sequential workload.  If you are only doing one
at a time, it will be a sequential workload.

--
Justin

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