[lkml]   [2008]   [Aug]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH] make poll_idle behave more like the other idle methods
Make poll_idle() behave more like the other idle methods.

Currently, poll_idle() returns immediately. The other
idle methods all wait indefinately for some condition
to come true before returning. poll_idle should emulate
these other methods and also wait for a return condition,
in this case, for need_resched() to become 'true'.

Without this delay the idle loop spends all of its time
in the outer loop that calls poll_idle. This outer loop,
these days, does real work, some of it under rcu locks.
That work should only be done when idle is entered and
when idle exits, not continuously while idle is spinning.

Signed-off-by: Joe Korty <>

Index: 2.6.27-rc4-git4/arch/x86/kernel/process.c
--- 2.6.27-rc4-git4.orig/arch/x86/kernel/process.c 2008-08-26 17:44:34.000000000 -0400
+++ 2.6.27-rc4-git4/arch/x86/kernel/process.c 2008-08-26 18:22:19.000000000 -0400
@@ -185,7 +185,8 @@
static void poll_idle(void)
- cpu_relax();
+ while(!need_resched())
+ cpu_relax();


 \ /
  Last update: 2008-08-27 16:37    [W:0.090 / U:4.132 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site