[Cbe-oss-dev] [PATCH 1/5] powerpc/spufs: provide context debug file

[Arnd Bergmann]

On Tuesday 01 July 2008, Jeremy Kerr wrote:
> From: Luke Browning <lukebrowning at us.ibm.com>
> 
> Add a ctxt file to spufs that shows spu context information that is used
> in scheduling. This info can be used for debugging spufs scheduler
> issues, and to isolate between application and spufs problems as it
> shows a lot of state such as priorities and dispatch counts.
> 
> This file contains internal spufs state and is subject to change at any
> time, and therefore no applications should depend on it.  The file is
> intended for the use of spufs kernel developers.
> 
> Signed-off-by: Luke Browning <lukebrowning at us.ibm.com>
> Signed-off-by: Jeremy Kerr <jk at ozlabs.org>

I'm still unhappy about this patch, because I think this is the
kind of information that should never be part of a public interface.
Much of the information in there is very specific to the implementation,
so it will be very hard to maintain ABI stability for this one, and I
assume doing that was not Lukes intention anyway.

I'm not saying anything against it being very useful, but I'm certain
that once we provide this file, people will start reyling on it in user
programs and we get into trouble.

I would be much happier if we could at least make the presence of this
file depend on a "debug" mount option or something like that.

	Arnd <><