Date: Mon, 09 Mar 1998 18:02:16 -0800 From: Dan Sugalski <sugalskd@osshe.edu> To: Christopher Masto <chris@netmonger.net>, perl5-porters@perl.com, nvp@mediaone.net Cc: hackers@FreeBSD.ORG Subject: Re: Perl, Threads, FreeBSD, High Weirdness Message-ID: <3.0.5.32.19980309180216.00a15320@osshe.edu> In-Reply-To: <19980309152332.35831@netmonger.net>
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At 03:23 PM 3/9/1998 -0500, Christopher Masto wrote:
>Here are the latest results of my investigations into _62's thread
>situation:
[Snip]
>Pretending the last line is fixed, this test still fails on FreeBSD
>(2.2.5-stable as of yesterday). I don't know why, but I do know that
>threads are simply not working. They do not run concurrently.
>
>This test program:
>
> use Thread;
>
> $t = Thread->new(sub { print "AAA\n" while 1; });
> while (1) {
> print "---\n";
> sleep 1;
> }
>
>Produces this output:
>
>---
>---
>---
>---
>---
>(ad infinitum)
>
>If the main program ever performs a $t->join or exits, the AAA thread
>takes over and actually can't be stopped with a ^C or ^\ (but kill -9
>from another session works).
>
>Either I'm completely misunderstanding the semantics of the Thread stuff
>(the documentation _is_ a bit skimpy right now (I will try to help remedy
>that if I ever get this working)), or something's truly screwy.
While I can't speak for FreeBSD, for OpenVMS this does work as expected--a
line of ---, then a jillion AAA lines with the odd --- scattered in there.
(Not many, I didn't let the test run too long :)
Dunno if it's an issue, but the POSIX threading does have a number of
different scheduling options for threads, and I had to do a special link on
OpenVMS to enable kernel threads. (Without the magic link option, multiple
threads wouldn't run on multiple processors) Depending on the defaults, I
can see this behaviour. (it looks like SCHED_FIFO's the default policy with
no thread rescheduling on blocking syscalls)
Maybe there are some special flags you need to feed to the C compiler, or
linker, or something.
Dan
---------------------------------------------"it's like this"--------------
Dan Sugalski (541) 737-3346 even samurai
SysAdmin have teddy bears
Oregon University System and even the teddy bears
sugalskd@ous.edu get drunk
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