Date: Sun, 20 Jun 2004 04:14:53 +0200 From: "Cyrille Lefevre" <clefevre-lists@9online.fr> To: <current@freebsd.org> Cc: hackers@freebsd.org Subject: -lthr vs. -pthread Message-ID: <008901c4566c$610d1300$7890a8c0@dyndns.org>
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Hi,
I'm currently working on enhancements to ps w/ "Garance A Drosehn".
I've just added some thread related stuffs and to see them, I'm
using the following program :
#define _REENTRANT
#include <pthread.h>
#define NUM_THREADS 5
#define SLEEP_TIME 10
void *sleeping(void *);
pthread_t tid[NUM_THREADS];
int
main(int argc, char *argv[])
{
int i;
for (i = 0; i < NUM_THREADS; i++)
pthread_create(&tid[i], NULL, sleeping, (void *)SLEEP_TIME);
for (i = 0; i < NUM_THREADS; i++)
pthread_join(tid[i], NULL);
printf("main() reporting that all %d threads have terminated\n", i);
return (0);
}
void *
sleeping(void *arg)
{
int sleep_time = (int)arg;
printf("thread %d sleeping %d seconds ...\n", thr_self(), sleep_time);
sleep(sleep_time);
printf("\nthread %d awakening\n", thr_self());
return (NULL);
}
then, I compile this one in 2 way :
# cc -o thread thread.c -lthr
and
# cc -pthread -o pthread thread.c
here is some of the "new ps" outputs :
"lwp" is the thread id and "nlwp" the the number of threads.
-q switch in posix mode (aka SystemV) and -C select processes
by name (a la pgrep).
# ./thread& sleep 1; ps -H -O lwp,nlwp -qC thread
(thread, using -H)
PID LWP NLWP TTY TIME COMMAND
85146 100005 6 ttyp0 00:00:00 thread
85146 100004 6 ttyp0 00:00:00 thread
85146 100003 6 ttyp0 00:00:00 thread
85146 100002 6 ttyp0 00:00:00 thread
85146 100001 6 ttyp0 00:00:00 thread
85146 85146 6 ttyp0 00:00:00 thread
# ./pthread& sleep 1; ps -H -O lwp,nlwp -qC thread
(pthread, using -H)
PID LWP NLWP TTY TIME COMMAND
96689 100002 2 ttyp0 00:00:00 pthread
96689 96689 2 ttyp0 00:00:00 pthread
is it normal that -pthread only forks only 1 thread where
-lthr forks 5 of them ?
# ./thread& sleep 1; ps -O lwp,nlwp -qC thread
(thread ot pthread, not using -H)
PID LWP NLWP TTY TIME COMMAND
73718 100005 6 ttyp0 00:00:00 thread
is it normal that the selected process is the last forked thread and
not the thread owner (father) ?
PS : using -lc_r, there is no thread at all, but I suppose this is an
expected behaviour.
CC -current and -hackers
Cyrille Lefevre.
--
mailto:clefevre-lists@9online.fr
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