Re: [Sbcl-devel] Status of native thread support#

Tue Jul 20 01:07:04 2004

Bcc: dan
To: sbcl-devel <at> lists.sourceforge.net
Subject: Re: [Sbcl-devel] Status of native thread support?

Edi Weitz writes:

> FWIW, I just tried the threaded CL-PPCRE tests again (I had an email
> exchange with Cristophe about this some months ago) and they still
> fail with SBCL 0.8.12 on Debian unstable. (Kernel is 2.6.6.) They run
> fine with Lispworks' green threads and they used to run fine with
> Scieneer's native threads when I had access to their 1.1 trial
> version.

The CL-PPCRE thread tests seem to work quite nicely as a test of
thread creation/exiting, which had a number of exciting race
conditions.  You may (and everyone else using or wanting to use
threaded SBCL may also) want to check out 0.8.12.42 which fixes at
least three of these and seems to run the threaded tests in cl-ppcre
0.7.9 quite happily.

This also fixes the thundering herd at thread gc rather more cleanly
than inserting sched_yields around the place: thanks to Juho Snellman
and Christophe Rhodes on #lisp for pointing this stuff out.

So, unless Bill advises to the contrary, SBCL will shortly be going
into code-mostly-freeze for the 0.8.13 release.  Therefore it would be
a really good thing if people would test their threaded stuff for
regressions /now/ instead of leaving it a week: then any bugs can be
fixed in time for this month instead of next.

(Incidentally, your threaded-scan function seems to be doing incf of
a shared variable COUNTER without the aid of a lock; this is probably
not guaranteed to work everywhere.  I think it happens to work in SBCL
(if so, mostly because it happens to work on x86), but you probably
want to have some kind of atomic-incf there, or protect it with a
mutex)


-dan

-- 
"please make sure that the person is your friend before you confirm"