From: Maximilian Gass Date: 2010-02-05T18:49:51+09:00 Subject: [ruby-core:28062] [Bug #1820] Always spawns a thread that loops on the futex syscall Issue #1820 has been updated by Maximilian Gass. It is not using 100% of one core, not at all. But it causes frequent wakeups that prevent the CPU from going to sleep. I first stumbled upon this by using powertop. Did you run strace with -f to follow the extra thread it creates? Otherwise you will just attach to the first one and not notice the other one. I doubt the problem is related to readline at all. The looping also happens when you run just ruby instead of irb. ---------------------------------------- http://redmine.ruby-lang.org/issues/show/1820 ---------------------------------------- http://redmine.ruby-lang.org