Re: [Cbe-oss-dev] [RFC, PATCH 4/4] Add support to OProfile for profiling Cell BE SPUs -- update

[Maynard Johnson <maynardj@us.ibm.com>]

Arnd Bergmann wrote:

> On Sunday 04 February 2007 00:49, Maynard Johnson wrote:
>  
>
> > I seem to recall looking at this option a while back, but didn't go that 
> > route since struct spu_context is opaque to me.  With such a teqnique, I 
> > could then use a simple 16-element array of  pointers to cached_info 
> > objects, creating them as needed when spu_context->profile_private is 
> > NULL.  I suppose the better option for now is to add a 
> > get_profile_private() function to SPUFs, rather than requiring 
> > spu_context to be visible.
> >    
>
> Yes, that sounds good. Note that the file providing the 
> spufs_get_profile_private (and respective spufs_set_profile_private)
> functions needs to be compiled into the kernel then in case oprofile
> gets linked in but spufs is a module.
>  
Hmm . . . we already depend on the register/unregister functions in 
sched.c, so my patch changes the oprofile Kconfig to default to 'm' and 
'depends on SPU_FS'.

> I think it would also be necessary to have another interface for cleaning
> up this data when spufs destroys the context. That could possibly
> a variation of the existing notifier call, or a new call, or you
> establish the convention that if the private pointer is non-NULL,
> spufs will kfree it.
>  
Yes, I was thnking along the lines of your last suggestion.  I presume 
OProfile gets notified (object_id == 0) before the context is actually 
destroyed.  At that time, we would NULL-out the reference to the 
cached_info, so then SPUFS would kfree it at destroy time.

-Maynard

> 	Arnd <><
>  


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/