On Tuesday, 03 February 2009 at 18:11, Warren Togami wrote: > I talked with Jakub Jelinek to ask his recommendation of how Fedora 11 > should proceed. > > Jakub recommends i586.rpm for Fedora 11, because it doesn't gain us much > of anything to go with i686 minimum. The benefits of i586 to i686 are > simply not important because cmov is usually not a worthwhile > optimization on ia32. You sometimes find some testcase where cmov > improves something, but often you find one where it pessimizes something > as well. I'd like to see a case (not involving Pentium 4) where using cmov is slower than not using it. It definitely is faster for decoding H.264 in FFmpeg for example. > 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. [...] > Jakub recommended doing comparison tests of -m32 -march=i586 > -mtune=generic vs. -m32 -march=i686 -mtune=generic with Spec2k and > Spec2006 benchmark tools. Anyone interested in trying this? Are these tools' sources available somewhere? Last I searched I couldn't find them. > He also wants gcc-4.4 to go into dist-f11 immediately after Alpha, even > if we are not doing the mass rebuild just yet. It is ABI compatible so > shouldn't cause any problems on its own. Meanwhile it will allow > maintainers to fix some problematic packages sooner. +1 > In related news, cebbert wants to do the following to the F-11 kernel: > - Eliminate the current i686 kernel. > - i686 hardware would get i686 PAE by default. Not all i686 hardware is PAE capable. > - i586 kernel becomes i686, except without cmov. This is primarily so > people don't complain when they realize they have the "i586" kernel. And this will be installed on anything that's not PAE capable? Regards, R. -- Fedora http://fedoraproject.org/wiki/User:Rathann RPMFusion http://rpmfusion.org | MPlayer http://mplayerhq.hu "Faith manages." -- Delenn to Lennier in Babylon 5:"Confessions and Lamentations" -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
