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

Chase Venters
2006-06-16T21:15:34Z

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)
> -
> 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/
>