1 process, 2 threads, how many cpus?
nb_root at videotron.ca
Mon Nov 28 02:01:46 GMT 2005
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."
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,
FreeBSD 7.0-CURRENT #2: Sat Nov 26 10:55:30 EST 2005
nicblais at clk01a:/usr/obj/usr/src/sys/CLK01A
PGP? (updated 16 Nov 05) : http://www.clkroot.net/security/nb_root.asc
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