Re: FOR REVIEW: New x86-64 vsyscall vgetcpu()

[Chase Venters]

On Fri, 16 Jun 2006, Andi Kleen wrote:

> > To this last point, it might be more reasonable to map in a page that
> > contained a new structure with a stable ABI, which mirrored some of
> > the task_struct information, and likely other useful information as
> > needs are identified in the future.  In any case, it would be hard
> > to beat a single memory read for performance.
>
> That would mean making the context switch and possibly other
> things slower.
>
> In general you would need to make a very good case first that all this
> complexity is worth it.
>
> > Cache-coloring and kernel bookkeeping effects could be minimized if this
> > was provided as an mmaped page from a device driver, used only by
> > applications which care.
>
> I don't see what difference that would make. You would still
> have the fixed offset problem and doing things on demand often tends
> to be even more complex.
>
>
> -Andi (who thinks these proposals all sound very messy)
> -
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