On Sunday 16 October 2005 19:31, Nix wrote: > On Sat, 15 Oct 2005, Joel Palmius wrote: > > On Sat, 15 Oct 2005, Blaisorblade wrote: > >> One question - -march=athlon64 is also supported by GCC (even if I don't > >> know how much it helps).
> > Yup. Or -march=k8. > These are synonyms for the same thing, as is -march=opteron and > -march=athlon-fx. > -march=x86-64 is similar but disables use of 3DNow intrinsics (not that > those are used much yet unless you use vector stuff a lot: I guess when > OpenMP and autovectorization start to turn up in GCC trunks, we'll see > more use from them). > (As far as I can tell PROCESSOR_K8 and PROCESSOR_ATHLON are identical in > GCC except for bitness, a few predefined macros, and scheduling. I don't know, but I exactly expected scheduling to be changed. You may correct me (you know more about GCC), but I expect scheduling to make some difference. Btw, I still haven't done the tricks to make UML use host cpu features - it's still compiled with default GCC settings for this. Actually, for the host kernel (which uses arch=k8, see arch/i386/Makefile)) SSEx makes no difference (the kernel can't allow GCC to use FP on its own, as you probably know - the kernel must explicitly enable FP state saving, and even then there are strict rules on FP usage, for instance you must be atomic). > Of course the first of those changes ia a biggie, but you're not losing > much by having GCC consider 32-bit code on your K8 to be running on an > Athlon.) -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade ___________________________________ Yahoo! Messenger: chiamate gratuite in tutto il mondo http://it.messenger.yahoo.com ------------------------------------------------------- This SF.Net email is sponsored by: Power Architecture Resource Center: Free content, downloads, discussions, and more. http://solutions.newsforge.com/ibmarch.tmpl _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
