Date: Sun, 27 Nov 2005 21:01:32 -0500 From: Nicolas Blais <nb_root@videotron.ca> To: freebsd-threads@freebsd.org Subject: 1 process, 2 threads, how many cpus? Message-ID: <200511272101.38903.nb_root@videotron.ca>
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[-- Attachment #1 --] As I was looking around the net for some information on pthreading in FreeBSD, I came across something that got my attention: "The native user threads cannot concurrently run more than one thread on separate processors at one time. If you are running a single process with multiple CPU-intensive threads in hopes of utilizing multiple processors, you must use Linuxthreads to get this performance." (http://www.unobvious.com/bsd/freebsd-threads.html) Is this still applicable now (FreeBSD 5.4/6/CURRENT)? I'm writing a software that runs 1 process and multiple threads (with pthread) that performs calculations and I was wondering if on a SMP system the threads will run on an independant cpu. It would be quite pointless to have all threads of the same process sharing a single cpu. Also, no matter how many threads I create within a process, 'top' only reports 2 threads. The following 'top' run reports my software ('aite') as using 2 threads (when it actually created 4): CPU states: 99.2% user, 0.0% nice, 0.8% system, 0.0% interrupt, 0.0% idle Mem: 257M Active, 1422M Inact, 189M Wired, 85M Cache, 112M Buf, 49M Free Swap: 2000M Total, 2000M Free PID USERNAME THR PRI NICE SIZE RES STATE TIME WCPU COMMAND 89728 nicblais 2 20 0 4420K 2384K ksesig 0:18 77.44% aite Any insight appreciated, Nicolas. -- FreeBSD 7.0-CURRENT #2: Sat Nov 26 10:55:30 EST 2005 nicblais@clk01a:/usr/obj/usr/src/sys/CLK01A PGP? (updated 16 Nov 05) : http://www.clkroot.net/security/nb_root.asc [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (FreeBSD) iD8DBQBDimUC4wTBlvcsbJURAlP0AKCUuZJ7/+tqZrCfS9eaJu+jVkAmeQCfYf/r kgOWgxV8yIktXm3YxYwAIas= =z+ia -----END PGP SIGNATURE-----help
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