Subject: Re: Kernel 2.6 on MPC8xx performance trouble...

From: Marcelo Tosatti <[email-masked]>
Date: Fri, 28 Oct 2005 13:30:59 -0200

On Fri, Oct 28, 2005 at 08:57:44AM +0200, David Jander wrote:
> 
> Hi all,
> 
> Many people have said it before: 2.6 has a performance penalty specially for 
> embdedded systems.
> But now that I have 2.6 running on our 100MHz MPC852T based board, I was 
> shocked to see the result:
> The most simple task doing nothing but a closed loop of integer math runs at 
> _half_ the speed compared to kernel 2.4.25!!!!!

David,

Do you have CONFIG_PIN_TLB enabled?

If you do, please patch this in:

http://www.kernel.org/git/?p=linux/kernel/git/marcelo/8xx-fixes;a=commitdiff;h=a41ba028534c45280170c05c23609ea84f34b38a

And select DEBUG_PIN_TLBIE.