Hi All, Thanks to testing from several people we seem to be narrowing down on which debug options are causing the biggest performance hit in rawhide kernels. As of right now, SLUB_DEBUG is the worst offender. Fortunately, you can disabled that via the slub_debug=- command line switch. The other option that causes a big hit is PROVE_RCU, but by itself it isn't a major issue. Combined with SLUB_DEBUG though, it will really impact things. I've started collecting some of these test results here: https://fedoraproject.org/wiki/KernelDebugOptions I'll continue to update that as people provide results. As a note, the 3.8-rc6 kernel will not have debug options disabled. We really only have a few major options left to get through, so we'll continue with turning them on. The nodebug rawhide repo will contain a build without the debug options set as usual. I expect that -rc7 will go back to the normal method of doing things. If you have questions/comments please drop us a line on the list! josh _______________________________________________ kernel mailing list kernel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/kernel
