On 09/10/2013 09:24 AM, Linus Torvalds wrote: > On Tue, Sep 10, 2013 at 8:29 AM, Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> wrote: >>> >> also.. yuck on using "dec" >> "dec" sucks, please use "sub foo ,1" instead > > That's a bigger instruction, largely due to the constant. > >> (dec sucks because of its broken flags behavior; it creates basically a >> bubble in the pipeline) > > Intel could (and should) just fix that. It's "easy" enough - you just > need to rename the carry flag as a separate register (and make sure > that the conditional instructions that don't use it don't think they > need it). > > In fact I thought Intel already did that on their large cores. Are you > sure they still have trouble with inc/dec? > Big cores are fine, but Atom (and presumably Quark) might still suffer a performance penalty. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
