Re: [gentoo-user] Is my system (really) using nptl

[Canek Peláez Valdés]

On Fri, Oct 12, 2012 at 8:24 AM, Timur Aydin <ta@××××××.org> wrote:
> Hi,
>
> I have done many tests on my ~x86 system to confirm that it is nptl based:
>
> - I have the nptl and nptlonly use flags in my make.conf and my system
> is up to date.
>
> - Running /lib/libc.so.6 shows:
>
> ta@bonsai ~ $ /lib/libc.so.6
> GNU C Library stable release version 2.15, by Roland McGrath et al.
> Copyright (C) 2012 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.
> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
> PARTICULAR PURPOSE.
> Compiled by GNU CC version 4.5.3.
> Compiled on a Linux 3.5.0 system on 2012-09-10.
> Available extensions:
>         C stubs add-on version 2.1.2
>         crypt add-on version 2.1 by Michael Glad and others
>         Gentoo patchset 21
>         GNU Libidn by Simon Josefsson
>         Native POSIX Threads Library by Ulrich Drepper et al
>         Support for some architectures added on, not maintained in glibc
> core.
>         BIND-8.2.3-T5B
> libc ABIs: UNIQUE IFUNC
> For bug reporting instructions, please see:
> <http://www.gnu.org/software/libc/bugs.html>.
>
> - getconf also indicates nptl:
>
> ta@bonsai ~ $ getconf GNU_LIBPTHREAD_VERSION
> NPTL 2.15
>
>
> Yet, when I look at the process list, I am seeing all programs that use
> threads having uniquey pid's for each thread. I even compiled a simple
> program that just creates 5 threads, each sleeping forever. Again, each
> thread had a unique pid.
>
> I have also checked the kernel config. FUTEX support was enabled, but
> the top level selector (EXPERT options) was not selected. I guess the
> top level selector just exposes the FUTEX selector and doesn't really
> affect whether it is enabled or not.
>
> So, what I am wondering now, is my system configured for NPTL or not?

You arouse my curiosity. Maybe there is a bug in glibc in ~x86; I'm
running stable (but with vanilla sources 3.6.0), and I have basically
the same setup as you: my glibc states that it has NTPL, getconf also
says it so, and I have FUTEX support enabled. I just don't set ntpl
nor ntplonly in my use flags (I was under the impression they were
enabled by default). My little program with 5 threads gets listed as a
single PID in my "ps x" output.

sys-libs/glibc-2.15-r2, no use flags set (except for multilib, which
is mandatory)
sys-kernel/vanilla-sources-3.6.1

Regards.
-- 
Canek Peláez Valdés
Posgrado en Ciencia e Ingeniería de la Computación
Universidad Nacional Autónoma de México