From: KOSAKI Motohiro <kosaki.motohiro@...>
Date: 2010-05-19T19:16:39+09:00
Subject: [ruby-core:30310] Re: [Feature #3176] Thread#priority= should 	actually do something

Hi

> Kosaki, I have tried using setpriority on linux to get the OS to handle priorities, but it failed
> in the same way that pthread_setschedparam did; the test script would never finish and
> wouldn't even respond to ^C. I have no idea why this is failing so badly. (Maybe a bug in
> linux?? More likely a bug in my understanding.)

Which test case do you use?  I'll investigate the issue.


> In any case, another problem with this approach is that you won't readily be able to set
> a thread to higher priority than the main thread. Altho there may be ways around this,
> they come with their own issues. For instance, if a ruby process is started at the lowest
> possible priority (highest nice level) it won't be �possible to have threads within that
> process be a different priority at all. On reflection, it seems better for ruby to manage its
> own thread priority queue (at least on linux) and have a guaranteed level of support for
> priorities and fixed number of available priorities.

JVM have the same limitation. Then, I guess JRuby too.

http://java.sun.com/j2se/1.5.0/docs/guide/vm/thread-priorities.html#150

So, I think we can accept the limitation too.