Re: Performance tweaks

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Mitchell Blank Jr a écrit :

> > For uniprocessors this:
> >
> > const int cpu = smp_processor_id();
> > if (dev->xmit_lock_owner != cpu) {
> >
> > generates faster code than this:
> >
> > int cpu = smp_processor_id();
> > if (dev->xmit_lock_owner != cpu) {
>
> That's really odd, I would have assumed that gcc would have optomized
> the variable away, but your experiment indicates otherwise. Maybe we need
>
> #ifdef CONFIG_SMP
> typedef int processor_id_t;
> #else
> typedef const int processor_id_t;
> #endif

move the #ifdef/endif pair in includes is better. Maybe a __SMP as :
#ifdef CONFIG_SMP
        #define __SMP
#else
        #define __SMP const
#endif

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			         	 --Thierry
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• Next message: Pedro M. Rodrigues: "[OT] 4 port ethernet cards in Linux?"
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