Date: Fri, 09 Dec 2011 06:03:26 -0500 From: George Mitchell <george+freebsd@m5p.com> To: freebsd-stable@freebsd.org Subject: SCHED_ULE should not be the default Message-ID: <4EE1EAFE.3070408@m5p.com>
next in thread | raw e-mail | index | archive | help
dnetc is an open-source program from http://www.distributed.net/. It tries a brute-force approach to cracking RC4 puzzles and also computes optimal Golomb rulers. It starts up one process per CPU and runs at nice 20 and is, for all intents and purposes, 100% compute bound. Here is what happens on my system, running 9.0-PRERELEASE, with and without dnetc running, with SCHED_ULE and SCHED-4BSD, when I run the command: time make buildkernel KERNCONF=WONDERLAND (I get similar results on 8.x as well.) SCHED_4BSD, dnetc not running: 1329.715u 123.739s 24:47.95 97.6% 6310+1987k 11233+11098io 419pf+0w SCHED_4BSD, dnetc running: 1329.364u 115.158s 26:14.83 91.7% 6325+1987k 10912+11060io 393pf+0w SCHED_ULE, dnetc not running: 1357.457u 121.526s 25:20.64 97.2% 6326+1990k 11234+11149io 419pf+0w SCHED_ULE, dnetc running: Still going after seven and a half hours of clock time, up to compiling netgraph/bluetooth. (Completed in another five minutes after stopping dnetc so I could write this message in a reasonable amount of time.) Not everybody runs this sort of program, but there are plenty of similar projects out there, and people who try to participate in them will be mightily displeased with their FreeBSD systems when they do. Is there some case where SCHED_ULE exhibits significantly better performance than SCHED_4BSD? If not, I think SCHED-4BSD should remain the default GENERIC configuration until this is fixed. -- George Mitchell
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4EE1EAFE.3070408>