On Thursday 04 October 2007 20:41:07 Dave Jones wrote: > On Thu, Oct 04, 2007 at 08:21:59PM +0200, Andi Kleen wrote: > > On Thursday 04 October 2007 20:10:44 Dave Jones wrote: > > > On Thu, Oct 04, 2007 at 07:53:16PM +0200, Andi Kleen wrote: > > > > > > > > > The only vendor that ever implemented OOSTOREs was Centaur, and they > > > > > only did in the Winchip generation of the CPUs. When they dropped > it > > > > > from the C3, I asked whether they intended to bring it back, and the > > > > > answer was "extremely unlikely". > > > > > > > > > > > > > Do you know if it made a big performance difference? > > > > > > On the winchip, it was a huge win. I can't remember exact numbers, > > > but pretty much every benchmark I threw at it at the time showed > > > significant improvement. > > > > Significant as in >10%? > > "Worth about 10-20% performance" according to the 2.4.18pre9-ac4 > release notes: > http://www.linuxtoday.com/news_story.php3?ltsn=2002-02-14-015-20-NW-KN
Are there numbers for a newer kernel available too? > > > > But yes we should probably just remove this special case to make > > > > maintenance easier. > > > It's CONFIG_SMP anyway, which none of the winchips were. > > > > It's not. > > You're right it isn't now, but Nicks patch seems to change it so that it is. > > ... > > #ifdef CONFIG_SMP > #define smp_mb() mb() > #define smp_rmb() rmb() > -#define smp_wmb() wmb() > +#ifdef CONFIG_X86_OOSTORE > +# define smp_wmb() wmb() > +#else > +# define smp_wmb() barrier() > +#endif That is only for smp_wmb() which are always SMP only -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/