develooper Front page | perl.perl5.porters | Postings from February 2012

Re: [PATCH] Further eliminate POSIX-emulation under LinuxThreads

Thread Previous | Thread Next
From:
Robert Millan
Date:
February 13, 2012 02:39
Subject:
Re: [PATCH] Further eliminate POSIX-emulation under LinuxThreads
Message ID:
CAOfDtXPsjcMzpVbZ+Jv+bG9FnDz5Jqp3LSwK-=NTwW5B2tAn1A@mail.gmail.com
El 12 de febrer de 2012 12:42, Niko Tyni <ntyni@debian.org> ha escrit:
> [crossposted to the Debian GNU/kFreeBSD development list debian-bsd
>                         and the Perl 5 development list perl5-porters ]

Thanks for bringing this up.

>> This is also a complete non-issue in practice these days, LinuxThreads
>> was a Linux 2.4 thread implementation that nobody maintains
>> anymore[2], all modern Linux distros use NPTL threads which don't
>> suffer from this discrepancy.

This is not correct.  LinuxThreads is only obsolete on GNU/Linux, but
it is maintained and used on GNU/kFreeBSD because, contrary to what
its name would indicate, it's a reasonably portable pthread library
with few kernel-specific dependencies.

However...

> Under POSIX threads the getpid() and getppid() functions return the
> same values across multiple threads, i.e. threads don't have their own
> PID's. This is not the case under the obsolete LinuxThreads where each
> thread has a different PID, so getpid() and getppid() will return
> different values across threads.

The version of LinuxThreads used on GNU/kFreeBSD has been patched to
use kFreeBSD (kernel of FreeBSD) thread primitives, and thus future
releases of Debian GNU/kFreeBSD will no longer be affected by this
problem.

Debian "Squeeze" release *IS* affected, however.  It'd be better if
you could wait at least until there's a new release before breaking
compatibility with Squeeze users.

HTH

-- 
Robert Millan

Thread Previous | Thread Next


nntp.perl.org: Perl Programming lists via nntp and http.
Comments to Ask Bjørn Hansen at ask@perl.org | Group listing | About