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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Bert Wesarg <bert.wesarg@googlemail.com>
Subject: Re: [RFC] set the thread name
Cc: kosaki.motohiro@jp.fujitsu.com, Stefani Seibold <stefani@seibold.net>,
       linux-kernel <linux-kernel@vger.kernel.org>,
       linux-mm <linux-mm@kvack.org>,
       Andrew Morton <akpm@linux-foundation.org>, linux-api@vger.kernel.org
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(cc to linux-api)

> Hi,
> 
> On Tue, Jun 16, 2009 at 20:39, Stefani Seibold<stefani@seibold.net> wrote:
> > Currently it is not easy to identify a thread in linux, because there is
> > no thread name like in some other OS.
> >
> > If there were are thread name then we could extend a kernel segv message
> > and the /proc/<pid>/task/<tid>/... entries by a TName value like this:
> prctl(PR_SET_NAME, ...) works perfectly here.

Oops, but man page describe another thing.

       PR_SET_NAME
              (Since Linux 2.6.9) Set the process name for the calling process
              to arg2.                    ^^^^^^^^^^^^

Should we change man page? or change implementation?

I bet many developer assume the implementation is right.


> 
> Bert
> 
> /* -*- c -*- */
> 
> #define _GNU_SOURCE
> #include <unistd.h>
> #include <stdlib.h>
> #include <stdio.h>
> #include <string.h>
> #include <stdint.h>
> #include <stdbool.h>
> #include <math.h>
> #include <pthread.h>
> #include <sys/prctl.h>
> 
> void *
> thread(void *arg)
> {
>     unsigned long i = (unsigned long)arg;
>     char comm[16];
>     snprintf(comm, sizeof comm, "task %02lu", i);
>     prctl(PR_SET_NAME, comm, 0l, 0l, 0l);
> 
>     sleep(10);
> 
>     return NULL;
> }
> 
> int
> main(int ac, char *av[])
> {
>     pthread_t thr;
>     unsigned long i, n = 10;
>     char comm[16];
> 
>     printf("%u\n", getpid());
>     sleep(5);
>     snprintf(comm, sizeof comm, "master");
>     prctl(PR_SET_NAME, comm, 0l, 0l, 0l);
>     sleep(5);
> 
>     for (i = 0; i < n; i++)
>         pthread_create(&thr, NULL, thread, (void *)i);
> 
>     pthread_join(thr, NULL);
> 
>     return 0;
> }
> 
> >
> > Greetings,
> > Stefani
> >
> >
> > --
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