On Mon, Nov 19, 2012 at 3:37 PM, Eelco Dolstra <[email protected]> wrote: > Hi, > > On 19/11/12 15:28, Lluís Batlle i Rossell wrote: > >>>> But I imagine Eelco wants glibc to be built for 3.5 kernels or above. >>> >>> Stdenv has "--enable-kernel=2.6.35". >> >> Do you favour a higher value? > > Is there a good reason for a higher value? Certainly it can't be higher than > 3.2 since that's our default kernel. And of course people may well want to > run > Nixpkgs on Linux distributions that have much older kernels.
Looking at glibc's sources shows: /* statfs fills in f_flags since 2.6.36. */ #if __LINUX_KERNEL_VERSION >= 0x020624 # define __ASSUME_STATFS_F_FLAGS 1 #endif /* prlimit64 is available in 2.6.36. */ #if __LINUX_KERNEL_VERSION >= 0x020624 # define __ASSUME_PRLIMIT64 1 #endif /* sendmmsg is available in 2.6.39. */ #if __LINUX_KERNEL_VERSION >= 0x020627 # define __ASSUME_SENDMMSG 1 #endif /* getcpu is a syscall for x86-64 since 3.1. */ #if defined __x86_64__ && __LINUX_KERNEL_VERSION >= 0x030100 # define __ASSUME_GETCPU_SYSCALL 1 #endif The only performance-increaser is probably sendmmsg, for servers such as node.js and nginx. The others are probably not called a lot, so emulating them won't hurt. I would still opt for choosing --enable-kernel=3.2 (our current default kernel) That way, people can keep on using their old/current kernels on stdenv merge, and on every future stdenv-upgrade we move this number up to the previous default kernel version. A glibc-compat package (with --enable-kernel=2.6.16, which is glibc2.17's minimum anyway) will probably do the trick for people who want to test old kernel configs (yes this will cause rebuilds for them, but I think most usecases for these setup aren't that big and don't change too often) > > -- > Eelco Dolstra | LogicBlox, Inc. | http://nixos.org/~eelco/ > _______________________________________________ > nix-dev mailing list > [email protected] > http://lists.science.uu.nl/mailman/listinfo/nix-dev _______________________________________________ nix-dev mailing list [email protected] http://lists.science.uu.nl/mailman/listinfo/nix-dev
