From: Charles Oliver Nutter <charles.nutter@...>
Date: 2008-07-03T08:05:01+09:00
Subject: Re: Threads and Ruby

I単aki Baz Castillo wrote:
> El Mi辿rcoles, 2 de Julio de 2008, Charles Oliver Nutter escribi坦:
>> Robert Klemme wrote:
>>> On 02.07.2008 18:29, barjunk wrote:
>>>> 4 - Native threads are used in Jruby, and in Ruby 1.9 YARV
>>> JRuby yes.  I am not sure about 1.9 - I believe native threads are not
>>> yet completely supported there.
>> Ruby 1.9's threads are native, but they are not allowed to run in
>> parallel because most of the core structures in Ruby are not thread-safe
>> (as in kernel-level thread safe).
> 
> AFAIK one of the advantages of green threads is that they are a bit faster. 
> What is the purpose of native threads in Ruby 1.9 if they cannot run in 
> parallel?

I think there are several, but one I know of is that it simplifies the 
logic required to block on IO without blocking other threads, since you 
can just let another thread get scheduled (essentially unlock/lock GIL 
around the blocking IO). I'm not sure if they actually made that change 
though.

Actually, it's probably more of a stepping stone toward full native, 
parallel threads.

And green threads are no faster than regular threads, but are often 
cheaper to create.

- Charlie