Re: Tyan S2466 MPX integrated ethernet interrupt happy

[Shane Nay <shane@minirl.com>]

> > So, approximately 8.5 million ethernet interrupts.  The system is
> > noticably slower when streaming ethernet data, and it's sucking
> > up a lot more processing time than on my other much slower other
> > box. This box is running a stock 2.4.18 kernel from kernel.org
> > (i.e. no custom hacks).  It's running 2 1800+ XPs.
>
> That all looks normal.  Could you be more specific about
> the performance problems?  How much slower? Output from
> `top' and `ps'?  Any nasty messages in the system log?

No nasties in the syslog.  System usage from top averages 50% per 
CPU.  (By system I mean kernel usage, bounces between 70 and 30 per 
CPU)

> Looking at the ethernet driver won't help, I expect - it's
> as efficient as most any other driver.  If there is a problem,
> it lies elsewhere...

Gotcha, yes that could definetly be.  This was extraordinarily 
unscientific.  I was thinking maybe someone had seen something else 
like this on this platform.  So, I'll write a test that isolates 
ethernet from other stuff like ide performance, etc.

> A kernel profile would be illuminating.  Build the kernel with as
> few modules as possible, boot the machine with `profile=1' and play
> with readprofile.

Will do when I return.

Thanks,
Shane Nay.
(Someone else noted their /proc/interrupts for the same machine, but 
my box had only been up for 1.5 hours :)