CPU frequency on a intel Q9300 CPU

Dave Jones davej at redhat.com
Wed May 21 02:13:57 UTC 2008


On Tue, May 20, 2008 at 04:57:16PM +0300, Henri Ala-Peijari wrote:
 > I have the Q9300 quad core CPU & Intel DG33FBC and Fedora9 64bit. By 
 > default it scales the cores to 2.0GHz but when I add to panel "CPU 
 > Frequency scaling monitor" and manually use that program to switch the 4 
 > cores to 2.5GHz I get the extra performance. I have tested this with 
 > BOINC. Default settings give about 5500 (Dhrystone) MIPS and 100%/2.5GHz 
 > give about 6900MIPS. Is there a way to set the cores permanently running 
 > 2.5GHz (now I have to repeat this after every restart)? The original 
 > BIOS detected the CPU 2.0GHz but after BIOS upgrade it shows 2.5GHz.

Hmm, sounds like ondemand is being a little aggressive to ramp things back
down after a busy period.  I guess for some reason BOINC is 'bursty' rather
than a long stretch of CPU-bound activity.
You can try adjusting the tunables in /sys/devices/system/cpu/cpu*/cpufreq/ondemand/
Reducing the sampling_rate is probably a good place to start.
(Note, it won't go lower than sampling_rate_min)

	Dave

-- 
http://www.codemonkey.org.uk




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