From: Christoph Kappel <unexist@...>
Date: 2009-12-04T22:48:52+09:00
Subject: [ruby-core:27036] Ruby causes nearly as much cpu wakeups as firefox

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Hi,

my questions is what does ruby when it's supposed to do nothing? Hopefully =
someone can enlighten me.

I am author of a window manager that uses a ruby vm for scripting stuff and=
 a user reported high cpu wakeups caused
by my wm. My first suggestions was I am doing something wrong, that's why I=
 started just an empty irb session and
checked the output of powertop again to sort out a fault of ruby.

Here is the cut-down output of powertop, the percentage is the percentage o=
f the overwall wakeups, the number in=20
brackets the amount of wakeups per second. (subtle is my window manager.)

  20.5% (133.5)           firefox : hrtimer_start_range_ns (hrtimer_wakeup)=
=20
  15.3% ( 99.5)            subtle : hrtimer_start_range_ns (hrtimer_wakeup)=
=20
  15.3% ( 99.5)               irb : hrtimer_start_range_ns (hrtimer_wakeup)=
=20

It's hard to believe that firefox with 13 tabs causes only 34 wakeups more =
than my irb session which basically waits for input.

I tested this with ruby 1.9.1p243, which actually has many oddities for me.=
 I will check this with other versions later.

Wbr, Christoph
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