On Jul 7, 2013, at 2:15 PM, Alfred Perlstein wrote: > On 7/7/13 2:01 PM, Garrett Cooper wrote: >> Why the magic number 12? > > Numbers higher seem to result in worse performance as reported by some > members of my team. >
We've run as high as -j48 ... number of logical cpu's "times-two" (it was on a box with 24 logical CPUs). We did buildworld in under 9 minutes. Beyond the "times-two" rule we saw a slow-down. NOTE: I might also mention this was on RAID-1 SSD. -- Devin >> On Jul 7, 2013, at 1:39 PM, Alfred Perlstein <alf...@freebsd.org> wrote: >> >>> Author: alfred >>> Date: Sun Jul 7 20:39:11 2013 >>> New Revision: 253002 >>> URL: http://svnweb.freebsd.org/changeset/base/253002 >>> >>> Log: >>> Document tip on how to build all kernels quickly. >>> >>> Modified: >>> head/Makefile >>> >>> Modified: head/Makefile >>> ============================================================================== >>> --- head/Makefile Sun Jul 7 19:58:14 2013 (r253001) >>> +++ head/Makefile Sun Jul 7 20:39:11 2013 (r253002) >>> @@ -32,6 +32,12 @@ >>> # targets - Print a list of supported TARGET/TARGET_ARCH pairs >>> # for world and kernel targets. >>> # toolchains - Build a toolchain for all world and kernel targets. >>> +# >>> +# "quick" way to test all kernel builds: >>> +# _jflag=`sysctl -n hw.ncpu` >>> +# _jflag=$(($_jflag * 2)) >>> +# [ $_jflag -gt 12 ] && _jflag=12 >>> +# make universe -DMAKE_JUST_KERNELS JFLAG=${jflag} >>> # >>> # This makefile is simple by design. The FreeBSD make automatically reads >>> # the /usr/share/mk/sys.mk unless the -m argument is specified on the >>> _______________________________________________ >>> svn-src-h...@freebsd.org mailing list >>> http://lists.freebsd.org/mailman/listinfo/svn-src-head >>> To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org" > _____________ The information contained in this message is proprietary and/or confidential. If you are not the intended recipient, please: (i) delete the message and all copies; (ii) do not disclose, distribute or use the message in any manner; and (iii) notify the sender immediately. In addition, please be aware that any message addressed to our domain is subject to archiving and review by persons other than the intended recipient. Thank you. _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
