Messages in this thread | | | From | Chris White <> | Subject | Re: 2.6.13/14 x86 Makefile - Pentiums penalized ? | Date | Wed, 14 Sep 2005 14:14:02 +0900 |
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On Tuesday 13 September 2005 15:04, Margit Schubert-While wrote: > In arch/i386/makefile we have : > cflags-$(CONFIG_MPENTIUMII) += -march=i686 $(call > cc-option,-mtune=pentium2) > cflags-$(CONFIG_MPENTIUMIII) += -march=i686 $(call > cc-option,-mtune=pentium3) > cflags-$(CONFIG_MPENTIUMM) += -march=i686 $(call > cc-option,-mtune=pentium3) > cflags-$(CONFIG_MPENTIUM4) += -march=i686 $(call > cc-option,-mtune=pentium4) > > According to the gcc 3.x doc, the -mtune is not avaliable for i686 > and, indeed, with 3.3.5 no -mtune is generated/used (make V=1).
That's correct, gcc 3.4 started the -mtune flag. Chances are if you really want the -mtune optimizations you're going to have to upgrade to gcc 3.4 or greater.
> This, of course, heavily penalizes P4's (the notorious inc/dec).
Are you referring to cpu cycle counts? Is there certain code that causes the kernel to perform that unfavorably by a large scale?
> Margit
Chris White [unhandled content-type:application/pgp-signature] | |