vrijdag, maart 05, 2004

NPTL issues

Yesterday, when testing the new TAO/ACE release, I noticed several tests were
failing. I assumed the mistake was ACE's, and debugged it for hours.
Unfortunately, the bug wasn't in ACE, but in the new POSIX threading library for
GNU/Linux (NPTL). This was rather disappointing to me, since I had read nothing
but good about the new threading implementation. The problem occurred because on
thread creation, NPTL just ignores the thread attributes. So, selecting a
scheduler or priority on thread creation doesn't work at all.

Furthermore, I noticed, that the new threading library only allowed me to create
255 threads, while LinuxThreads allowed me to create 1532 concurrent threads.
This is even stranger, as I have read reports on using 100k concurrent threads
with this new threading implementation. Apparantly, somethings wrong here, but I
can't figure out what could be causing this.

And, when I was trying to report these issues to the NPTL developers, I couldn't
find their mailinglist. I could find people referring to it, but I couldn't find
the address :-) Now, for some reason it's called the phil-list... not quiet easy
to associate this with a new threading lib.