RE: [microblaze-uclinux] BRAM

["Bret Ketchum" <bret.ketchum@xxxxxxxxxxxxxxxxxxx>]

	There must be a file, say:

./linux-2.4.x/arch/microblaze/mbvanilla.ld

	that describes to the linking process the base address of
interesting memory regions such as the area to use for stack. It just isn't
intuitive and I haven't taken the time to look.

	Bret

-----Original Message-----
From: owner-microblaze-uclinux@xxxxxxxxxxxxxx
[mailto:owner-microblaze-uclinux@xxxxxxxxxxxxxx] On Behalf Of
alucero@xxxxxxxxx
Sent: Wednesday, November 23, 2005 12:32 PM
To: microblaze-uclinux@xxxxxxxxxxxxxx
Subject: Re: [microblaze-uclinux] BRAM

What you comment is hard to get, since the stack is per process. However,
I'm 
working now in allocating the irq code at LMB (Block Ram). Theorically, the 
performace should increase. 

By now, the results are a bit strange. Under normal load the performance is 
fine, but under stress with ethernet interrupts the LMB code is not enough
to 
obtain always an aceptable latency (data used at irq should be at LMB too). 
The problem, I guess, is at the Microblaze cache and/or how the opb bus does

the arbitration. In the worst cases the latency should be higher, but till 
certain limits, which is not the case now.

I'll do a more specific explanation of the work in short, when I do all the 
tests facing with the LMB.

Coming back to your question, the work could be done but you should work 
creating a new memory zone to be managed by the uClinux kernel, and using a 
specfic flag to request space from this new zone. The kernel code should be 
modified to use this new memory zone for specific tasks. I'm working in a 
dirty way by now, modifying the create_module function to insert the data
and 
code module at LMB. This is just to test my implementation latencies. If you

are intested we could discuss how to resolve the implementation for this new

memoty zone.

Regards.

On Wednesday 23 November 2005 17:41, Bret Ketchum wrote:
> Has anybody considered or have actually run the uClinux kernel with
> the stack placed in BRAM? Does anybody have the recipe? Thanks in
> advance....
>
> 	Bret
>
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-- 
Alejandro Lucero
OS3, OS Serveis i Solucions
www.os3sl.com
Ingeniería Informática
+34 665687168
Av.Benjamin Franklin
CEEI. Parque Tecnológico de Paterna
Valencia(Spain)

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