Here's one question that I think would have an impact on how useful green threads are for many server apps:
If you are blocking on something like a database SELECT in one green thread, will the Ruby interpreter switch to another green thread while it's waiting for the response? Or does a blocking request block all green threads? Thanks, Pete On Sep 7, 2007, at 12:02 PM, Erik Hetzner wrote: > At Fri, 7 Sep 2007 11:43:24 -0700, > Ezra Zygmuntowicz <[EMAIL PROTECTED]> wrote: >> Hey Roger- >> >> No it would not be as fast at all. Current ruby threads are green >> threads, meaning that they do not use native OS threads so there is >> no real parallel execution. Ruby has an internal timer and just >> switches between threads really fast. So 10 mongrels will trounce one >> thread safe mongrel. >> >> Ruby 1.9, Jruby and Rubinius will eventually have native >> threads and may make this situation better but for now such is life. > > I don’t want to muddy the waters here, as my knowledge of Ruby > threading performance is minimal, but there isn’t any ‘real’ parallel > execution on any uniprocessor machine: it’s all emulation. Erlang uses > green threads (but calls them processes) but context switches quite a > bit faster (if I understand correctly) than native threads or > processes. True, on a multiprocessor machine Ruby isn’t going to take > advantage of the situation without native threads or running multiple > processes. But it may turn out that a mixture of multiple processes > AND green threads provides greater performance than plain old multiple > processes. > > This paper, for instance, from 2002, claims significantly better > performance on the JVM (Linux) with green threads than native. > <http://cselab.snu.ac.kr/member/naehyuck/papers/%5BJ14%5DComparative > %20performance%20evaluation%20of%20Java%20threads%20for%20embedded% > 20applications.pdf> > > best, > Erik Hetzner > ;; Erik Hetzner, California Digital Library > ;; gnupg key id: 1024D/01DB07E3 > _______________________________________________ > Mongrel-users mailing list > Mongrel-users@rubyforge.org > http://rubyforge.org/mailman/listinfo/mongrel-users _______________________________________________ Mongrel-users mailing list Mongrel-users@rubyforge.org http://rubyforge.org/mailman/listinfo/mongrel-users
