On Mon, May 21, 2012 at 12:25 AM, Xose Vazquez Perez <xose.vazquez@xxxxxxxxx> wrote: > Ruben Kerkhof wrote: > > >> It's even higher these days: >> >> grep NR_CPUS /boot/config-2.6.32-220.13.1.el6.x86_64 >> CONFIG_NR_CPUS=4096 >> >> I'm curious, has anyone measured what the memory overhead is of >> keeping NR_CPUS at 512? >> arch/x86/Kconfig says "This is purely to save memory - each supported >> CPU adds approximately eight kilobytes to the kernel image." If that's >> true, 512 cpus use 4MB, something I'm willing to live with on my 64bit >> servers. > > > https://bugzilla.redhat.com/show_bug.cgi?id=219457 That's on an ancient kernel. I believe some work has been done to reduce the overhead of cpu masks, see https://lkml.org/lkml/2012/2/15/546 for example. Regards, Ruben _______________________________________________ kernel mailing list kernel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/kernel
