On Wed, Feb 04, 2009 at 01:56:16AM +0100, Dominik 'Rathann' Mierzejewski wrote: >On Wednesday, 04 February 2009 at 01:34, Callum Lerwick wrote: >> On Tue, 2009-02-03 at 19:53 +0100, Dominik 'Rathann' Mierzejewski wrote: >> > > i686 to i686 w/ SSE2 would be a performance win, but that is >> > > clearly not an option for Fedora. >> > >> > SSE2-optimized libraries can be built and installed into /usr/lib/sse2. >> > Our ld.so already supports that. >> >> Why does SSE2 get this treatment, and not SSE? I've found SSE much more >> useful, and more common. SSE2 pretty much means P4 only on i386, Athlons >> didn't get SSE2 until the Athlon 64 and those should be running x86-64 >> anyway. Whereas there's a lot of Pentium 3s and Athlon XPs with SSE out >> there. > >I was wondering about the same thing. There's little to no documentation >on this subject so I had to dig into glibc sources to see how it works. >Apparently, glibc distinguishes some "features" for CPUs and those that >are "major" can have separate directories with optimized libraries. >In Fedora, "major" features are "i686" and "sse2". Whereas in Debian, >it's just "cmov", apparently. > >Can anyone shed more light here? Jakub? It extends to other architectures as well, fwiw. On PowerPC, you can have optimized libraries for ppc970,power4,power5,power6, and cell I believe. For Fedora, optimized libraries are built for power6/power6x. josh -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
