From: KOSAKI Motohiro <kosaki.motohiro@...>
Date: 2010-05-16T02:48:14+09:00
Subject: [ruby-core:30257] Re: [Feature #3176] Thread#priority= should 	actually do something

> The test result of caleb's testcase is,
>
> � �./ruby projects/thrprio/thrprio.rb
> � �315662770 209679 0.9986723818385312 true

Oops, please use following test instead caleb's one. because my
experimental patch haven't implement the way to chnage another thread
priority yet.

==================================================
c1 = c2 = 0
go=nil
t2 = Thread.new {
  t2.priority = -2;
  loop { c2 += 1 }
}
t1 = Thread.new {
  t1.priority = -1;
  loop { c1 += 1 }
}
go=true
sleep 5
t1.kill
t2.kill
puts "#{c1} #{c2} #{(c1-c2).to_f/(c1+c2)} #{c1.to_f/c2} #{c1 > c2}"
==================================================

Note: if we use /proc/sys/kernel/sched_compat_yield=1, we can get better result.

% taskset -c 1  ./ruby projects/thrprio/thrprio2.rb
16989126 12636726 0.14691223057483713 1.3444246555634742 true