RE: VIA IDE performance under 2.6.0-test7/8?

[James Finnie <jf1@IMERGE.co.uk>]

> Can you also send the output from "cat /proc/interrupts".
> It looks like you are not using IO-APIC, but instead using XT-PIC. 
> XT-PIC is a lot slower than IO-APIC.

I am indeed using the XT-PIC, but I was using it under 2.4.21 also, so I
doubt that is the cause of the problems, especially seeing as bartlomiej's
suggestion of increasing the read-ahead caching worked a treat.  

* Does anyone know why the values of the read-ahead caching are so different
between 2.4.x and 2.6.0-test7/8?  It seems to me that there are two
problems;
A) the meaning of the readahead value has changed (almost guaranteed, as in
2.4.21 I can't set anything above 255)
B) the default of 256 is low, as the default in 2.4 of 8 gave me 40Mb/sec
and the default of 256 in 2.6 gives me only 13Mb/s!

I couldn't see any reference to this change of behaviour anywhere on the
kernel mailing list archives.

> Just turn on SMB support in the "make menuconf", and it should enable 
> IO-APIC.

I'll give it a go just in case, however I don't like building kernels with
SMP when I have no need for it.

Cheers

James


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