Subject: Re: Interactive performance in -current
To: None <jmmv@menta.net>
From: Jason Thorpe <thorpej@wasabisystems.com>
List: tech-kern
Date: 10/25/2003 11:00:52
On Friday, October 24, 2003, at 09:19  AM, jmmv@menta.net wrote:

> Some more notes: when this happens, if I run top, I can see that the 
> CPU
> interrupt state is very high, over 75% (dunno if this has something to 
> do).
> And this started happening recently; it was much better before.  I 
> wonder if
> this has something to do with all those changes done recently to the 
> IDE
> code.
>
> Ideas about what changed?

Actually, it just occurred to me.

Do you use a custom kernel config file?  Perhaps you forgot to add the 
chip-specific driver for your PCI IDE controller.  The plain "pciide" 
is now PIO only, and will not use DMA if your chip supports it.  You 
need a chip-specific driver in your kernel config file to get the DMA 
capability.

Please post a dmesg for your new kernel so we can verify this.

         -- Jason R. Thorpe <thorpej@wasabisystems.com>