From: Charles Oliver Nutter <charles.nutter@...>
Date: 2008-07-01T09:55:46+09:00
Subject: Re: Threads and Ruby

ara.t.howard wrote:
> 
> On Jun 30, 2008, at 3:14 AM, Charles Oliver Nutter wrote:
> 
>> I hope you mean "for this situation". Processes are definitely not the 
>> solution to all problems.
> 
> well, given that the difference between processes and threads is an 
> incredibly small one for any modern os, and given that threads are *at 
> least* 100 harder to write deterministic code for (as your bug reports 
> regarding exception handling and ruby illustrate) i'd hazard a guess 
> that processes are *almost* always the correct solution when robust code 
> is desired.  in otherwords i'd take the position that one should always 
> use processes unless the reason becomes clear to use threads and, of 
> course ,there are indeed reasons.  this is mostly a comment on the 
> limitations of programmers and not on platforms or languages, 
> nevertheless the incredible ease of IPC with ruby makes it even more 
> true imho.

The fact that Ruby's threading has many breakages and pitfalls does not 
mean threading in general is the wrong way to fix things. Java threading 
works extremely well, with the only real requirement that you must 
either synchronize or avoid access to shared resources. 
Power...responsibility...etc. You can't damn threading because the 
standard implementation of Ruby doesn't do it well.

Perhaps you're right that when you only have access to green threads 
that processes are the right way to go, since green threads don't really 
gain you anything other than simulated asynchrony. But native threads 
done right are as good as separate processes, with the bonus that you 
can share fast in-memory access to resources if you're willing to accept 
the synchronization cost and complexity.

- Charlie