Bug #2264

Kernel#sleep thrashes the CPU on Windows

Added by Romulo Ceccon over 2 years ago. Updated 10 months ago.

[ruby-core:26275]
Status:Closed Start date:10/25/2009
Priority:Normal Due date:
Assignee:Usaku NAKAMURA % Done:

0%
Category:core
Target version:Ruby 1.8.7
ruby -v:ruby 1.8.7 (2009-06-12 patchlevel 174) [i386-mswin32_90]

Description

The attached script demonstrates a problem with Kernel#sleep: calling it while other threads are running severely interferes on performance. (You don't see a diference if there are only idle threads, though.) These are the results on a P4 3.2GHz with Windows XP (SP 3):

  before:
    0.047000   0.000000   0.047000 (  0.046875)
    0.062000   0.000000   0.062000 (  0.062500)
    0.063000   0.000000   0.063000 (  0.062500)
  after:
    9.359000  10.391000  19.750000 ( 20.109375)
    9.438000  10.094000  19.532000 ( 19.859375)
    9.890000  10.250000  20.140000 ( 20.468750)

I get similar results with ruby 1.8.7-p160, and it looks like the problem was introduced after Ruby 1.8.7-p72. Other branches are unaffected:

  > ruby -v
  ruby 1.8.6 (2009-08-04 patchlevel 383) [i386-mswin32_90]

  > ruby test_sleep.rb
  before:
    0.062000   0.000000   0.062000 (  0.062500)
    0.063000   0.000000   0.063000 (  0.062500)
    0.078000   0.000000   0.078000 (  0.078125)
  after:
    0.062000   0.000000   0.062000 (  0.062500)
    0.047000   0.000000   0.047000 (  0.046875)
    0.063000   0.000000   0.063000 (  0.062500)


  > ruby -v
  ruby 1.8.7 (2008-08-11 patchlevel 72) [i386-mswin32]

  > ruby test_sleep.rb
  before:
    0.047000   0.000000   0.047000 (  0.047000)
    0.062000   0.000000   0.062000 (  0.062000)
    0.047000   0.000000   0.047000 (  0.047000)
  after:
    0.047000   0.000000   0.047000 (  0.063000)
    0.062000   0.000000   0.062000 (  0.062000)
    0.063000   0.000000   0.063000 (  0.063000)


  > ruby -v
  ruby 1.9.1p0 (2009-01-30 revision 21907) [i386-mswin32]

  > ruby test_sleep.rb
  before:
    0.031000   0.000000   0.031000 (  0.031250)
    0.031000   0.000000   0.031000 (  0.031250)
    0.031000   0.000000   0.031000 (  0.031250)
  after:
    0.047000   0.000000   0.047000 (  0.046875)
    0.032000   0.000000   0.032000 (  0.031250)
    0.031000   0.000000   0.031000 (  0.031250)

test_sleep.rb (270 Bytes) Romulo Ceccon, 10/25/2009 01:23 am

History

#1
Updated by Yui NARUSE over 2 years ago

  • Status changed from Open to Assigned
  • Assignee set to Usaku NAKAMURA

#2
Updated by Usaku NAKAMURA over 2 years ago

  • Status changed from Assigned to Closed
Already fixed on ruby_1_8 branch, and shyouhei has stacked the patch on his backport list.

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