Bug 19672

Summary: ondemand is slow
Product: Power Management Reporter: Dan Hollocher (danielhollocher)
Component: cpufreqAssignee: cpufreq
Status: CLOSED CODE_FIX    
Severity: normal CC: florian
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.35 Subsystem:
Regression: No Bisected commit-id:

Description Dan Hollocher 2010-10-03 21:08:43 UTC 
I find ondemand is allot slower than conservative for cpu bound tasks.  My understanding is that performance wise, ondemand should be on par or slightly faster than conservative.

My chip is an intel core 2 duo, I think 4300.  I am using 2.6.35 from Ubuntu.

On the kraken benchmark, ondemand completes in   34216.6ms +/- 2.3%   where as conservative completes in   25699.3ms +/- 5.6%


Again, it is my understanding that ondemand should not have this much of a slowdown.
Comment 1 Florian Mickler 2011-01-24 13:01:27 UTC 
a fix for this has been merged in .37-rc1:
commit 3f78a9f7fcee0e9b44a15f39ac382664e301fad5
Author: David C Niemi <dniemi@verisign.com>
Date:   Wed Oct 6 16:54:24 2010 -0400

    [CPUFREQ] add sampling_down_factor tunable to improve ondemand performance