Re: Relicensing tracepoints and markers to Dual LGPL v2.1/GPLv2,headers to Dual BSD/GPL

[Arjan van de Ven]

On Mon, 26 Oct 2009 09:17:49 -0400
Pierre-Marc Fournier <pierre-marc.fournier@xxxxxxxxxx> wrote:

> Ingo Molnar wrote:
> > 
> > But i also disagree with it on a technical level: code duplication
> > is _bad_. Why does the code have to be duplicated in user-space
> > like that? I'd like Linux tracing code to be in the kernel repo.
> > Why isnt this done properly, as part of the kernel project - to
> > make sure it all stays in sync?
> > 
> 
> If you mean that this code should solely be used inside the kernel,
> then what you propose technically does not work. There is a very high
> cost to accessing kernel code from userspace. 

yeah 100 cycles is insanely high, that's at least the equivalent of...
say one cache miss.


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
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