Jivin Bou lays it down ...
> Hi all,
> 
> sorry for posting this again (I hope whoever could comment on the 
> original post "just lost it" :) ).
> I would appreciate anyone's thoughts on this.

Don't recall seeing it,  but then that doesn't mean a lot ;-)

> Hi all,
> 
> On a "normal" kernel (no special tuning), kernel space tasks have more
> priority than userspace ones? Is that correct?

Not as far as I know,  unless a kernel task increases it's priority
I think it is the same,  of course it can do whatever it likes,  you
would have to check.

> Here is what I am experiencing and trying to find a solution.
> 
> I have an IXP425 based board, running madwifi for the Atheros cards,
> acting as a wifi router. I also use userspace programs (boa http server
> and cgi apps) to configure it.
> When the board is on heavy load (Wireless stations connected to the
> board and pass lots of traffic), my web apps run extremely slow. Even
> the serial console responds that slow.

This is most likely due to interrupt load and "at interrupt time"
processing.  That is higher priority than processes.

> Is there a solution to this? Would CONFIG_PREEMPT help at all? Or for
> something like this you have to use a RT kernel?

NAPI can help,  there are many drivers in the kernel that implement it
and you may be able to apply the same techniques to whatever drivers are
causing your latencies.

> Assuming that the user space application can have a specific pid, is
> there any "patch" that can be applied to the kernel's scheduler to give
> it some more priority?
> 
> I cannot tell if this slow down occurs to kernel versus user space
> priorities, or to the bunch of interrupts per second.

You want to look into kernel profiling (profile and oprofile).

Cheers,
Davidm

-- 
David McCullough,  [EMAIL PROTECTED],   Ph:+61 734352815
Secure Computing - SnapGear  http://www.uCdot.org http://www.cyberguard.com
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