Thanks Shlomi. Your statement is a great guide to perl threads to me. I'm checking the AnyEvent module which looks wonderful.
Thanks again. Mon, 7 Feb 2011 12:30:32 +0200 письмо от Shlomi Fish <shlo...@iglu.org.il>: > > Well, let me quote the perlbot ( on Freenode's #perl ) factoid: > > [quote] > > <perlbot> Before you start implementing code using Perl's threads, > please remember that Perl's threads are not like other threads. Please see > http://perldoc.perl.org/perlthrtut.html to learn more; specifically the "What > kind of threads are perl threads?" section. Also see: > http://www.perlmonks.org/index.pl?node_id=288022 > > [/quote] > > Read these two resources and be enlightened. Threads do not work too well in > any of the P-languages, and I was told that threads in Python with its > notorious Great-Interpreter-Lock (GIL) suck - not "as bad as Perl" but still > pretty badly. I haven't tried threads in Lisp yet. > > Threads work pretty well in C, though they are extremely tricky to get right > for non-trivial programs, and they should be pretty OK in .NET too (and again > - quite tricky). Java and C++ may support threads nicely, but from what I > heard and know developing in them is painful and error-prone in itself. See > for example: > > http://lbrandy.com/blog/2010/03/never-trust-a-programmer-who-says-he-knows-c/ > > ("-c" there is "C++"). > > Some people say threads work very well in languages such as Erlang (where > threads are "green threads" and are also used as a kind of cheap abstraction, > and one can often spawn thousands of them on a machine with much fewer cores > or processors), Haskell and other purely functional languages, but I don't > know about that. > > In any case, if you want to do multi-tasking in Perl, you should something > like either forking and multi-processing or the recommendations here such as > POE, Net::Async, IO::Lambda, Reflex, AnyEvent, etc: > > http://perl-begin.org/uses/multitasking/ > > Some people think that threads should be avoided even in languages where they > have acceptable performance. See for example: > > http://www.faqs.org/docs/artu/ch07s03.html#id2923889 > > Furthermore, in regards to parallelism, in the Algorithm Design Manual > ( http://www.algorist.com/ ) says something that it is a good idea to split > the task in such ways that processing every task is self-contained and > requires as little interaction from the other tasks (IIRC). > > Personally, I've done some simple multi-threading projects, but can imagine > that more complex ones will be much more error-prone and hard to get right. > -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
