Hi! dist-f11-gcc44 currently has gcc 4.4.0-0.X packages, which are almost ready for moving into dist-f11, but before doing that, I'd like to discuss defaults. gcc on most arches has a switch to select which ISA it can assume (i.e. what minimum CPU will gcc compiled code run on) and a separate option to tune for the same or other CPU. Currently in Fedora the tuning is I believe: ISA tuning i386 -march=i386 -mtune=generic x86_64 -march=x86-64 -mtune=generic ppc lowest -mtune=power6 ppc64 lowest -mtune=power6 s390 -march=g5 -mtune=z9-109 s390x -march=z900 -mtune=z9-109 ia64 lowest -mtune=itanium2 sparc -mcpu=v7 -mtune=v7 sparcv9 -mcpu=v7 -mtune=v7 sparc64 -mcpu=ultrasparc -mtune=ultrasparc plus redhat-rpm-config tweaks something (-fasynchronous-unwind-tables and -mminimal-toc tweaking should IMHO remain in redhat-rpm-config): i686 -march=i686 -mtune=generic sparc -mcpu=v7 -mtune=ultrasparc sparcv9 -mcpu=ultrasparc -mtune=ultrasparc The question is, do we want to change anything on this for F11? E.g. I believe Fedora hasn't shipped an i386 or i486 kernel for years, and especially the -march=i386 vs. -march=i486 difference is significant (-march=i386 doesn't have sufficient atomic instructions). The only -lpthread library we are using is NPTL and that doesn't support i386 anyway, so I think we should either use -march=i486 or -march=i586 (the latter has 8 byte compare and swap instruction) as the default, when -march= isn't specified. Similarly, I wonder what CPUs we want to support in Fedora for PowerPC, if e.g. -march=power4 default wouldn't be possible. On s390, is somebody running Fedora on some 31-bit hw still (G5/G6), or could we safely default to -march=z900 for -m31 as well and say -mtune=z10? On sparc I guess we could just -mcpu=ultrasparc -mtune=ultrasparc always, given that the 32-bit support is being dropped. Another question is if we finally could bump the minimum supported kernel version in Fedora 11 glibc. Currently Fedora 10 glibc requires 2.6.9 or later kernel, which means it can't assume a lot of stuff (e.g. private futexes, a lot of added syscalls etc.), which means it has to test for them at runtime of every program (e.g. every threaded program does a dummy futex syscall to check for private futexes, for futex realtime clock support and has to use variables for this, instead of oring constants in the mutexes etc., and glibc has to check for ENOSYS and have fallbacks compiled in). 2.6.9 default comes I think still from the RHEL4 kernels. Could we bump this ideally to 2.6.29? It would mean Fedora 11 userland only runs on 2.6.29 and later kernels, but we could gain speed and decrease size of glibc shared libraries. For the -march/-mcpu default changes, I think nothing is required from the koji build infrastructure (I don't think there are 31-bit mainframes around in koji/brew and I don't think there are 32-bit powerpcs or i386/i486s among the build boxes either), on the other side that decision has to be made almost immediately (before the world is rebuilt with gcc 4.4.0). For glibc --enable-kernel= default this requires that all koji build boxes and anything else that needs to run Fedora 11 binaries runs at least 2.6.29 kernels, but the change might be still delayed for a few weeks. Jakub -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
