Re: Did I hear you folks might be interested in POSIX threads?
On Wed, Dec 12, 2001 at 03:44:49PM -0500, Bill Abt wrote:
> > > if you're interested. Most of
> > > the things missing here are hurd and mach specific things as signalling,
> > > stack allaction and some other things. Those things also need to be done
> > > with NGPT.
>
> Are you saying that this stuff is still missing from the kernel? I certainly
> hope not ;-)
A misunderstanding, it seems :)
We of course do have Unix signals, and they work (mostly) as they should.
However, those signals are implemented almost exclusively in user space, in
glibc and the relevant Hurd servers. I don't know intimately how the signal
code works, but Igor posted a summary of it on this list a while ago (in
case you are interested, I could dig it up).
Anyway, the bottom line is that the glibc signal code for the Hurd runs in
its own thread in every program linked to glibc (so, even single-threaded
programs run with two threads in the Hurd, the normal application thread you
are aware of and the signal thread in glibc you are not aware of). Therefore,
threading is really a very elemental part of the Hurd system and the Hurd's
version of glibc. So, this code has to be ported to pthreads if we want to
switch to it. As far as I know, this porting of the glibc signal code on
the Hurd to pthreads is non-trivial. And that porting is what Jeroen was
talking about.
I don't think this has much to do with the actual pthread implementation
used, except that, because glibc in the Hurd uses threading itself, pthreads
for the Hurd should be integrated closely with glibc, and that we need one
or two features in the threading package that goes beyond POSIX threads
(condition implies, I think, from hearsay). For you it means, if we are
going to use NGPT, we want it to be included in glibc and we want it to
support the extra feature(s) we need (I think it is really only one, but I
never checked).
Thanks,
Marcus
--
`Rhubarb is no Egyptian god.' Debian http://www.debian.org brinkmd@debian.org
Marcus Brinkmann GNU http://www.gnu.org marcus@gnu.org
Marcus.Brinkmann@ruhr-uni-bochum.de
http://www.marcus-brinkmann.de
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