Red Hat Bugzilla – Bug 124511
1.2 GHz computer running at slower CPU speed (800 MHz)
Last modified: 2007-11-30 17:10:43 EST
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Description of problem:
I have a IBM Thinkpad T23 which has a clean install of Fedora Core 2.
It is running noticably slower, and looking at /proc/cpuinfo, it
seems that the 1.2 GHz processor is running at 800 MHz. It seems that
the speedstep is permanently set to a lower CPU frequency -- even when
the machine is plugged in and lots of applications are running.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Boot FC2
2. Look at /proc/cpuinfo
Actual Results: running at slower speed than it should be
Created attachment 100618 [details]
output of cat /proc/cpuinfo > cpuinfo.txt
1) does this go away if you do
chkconfig --level 345 cpuspeed off
cpuspeed is the speedstep daemon that will slow the cpu down when the
machine is idle. It's possible that its somewhat mistuned for you
system. If you're up for it you can tweak the configuration file;
is the homepage of the program, /etc/cpuspeed.conf the configuration file.
I've stopped cpuspeed as above and rebooted, and the first time, it
showed it running at 1.2 GHz, but now, it is back to 800 MHz. I am
not sure of what is changed, as cpuspeed is not running now (as shown
from ps -aef).
Ok, I think I understand what I am seeing. With cpuspeed disabled,
if I boot with the laptop on battery power, I get 800 MHz all the
time, even if I later plug it in.
if I boot with the laptop plugged in, I get 1.2 GHz.
I guess the BIOS sets the initial speed, and without the cpuspeed
daemon working properly, there is no change when I switch between
battery and outlet power.
I think there are files under /sys that you can use to change the CPU
speed from the command line (as root). Right now I'm on a PowerBook G3
(fixed at max CPU speed) so I'll have to refresh my memory on the
details later. (Actually, cpufreq support for this PB G3 would be a
nice enhancement, but that's unrelated to this bug.)
Or, you could enable cpuspeed and then "killall -SIGUSR1 cpuspeed" to
have it lock the CPU at 1.2GHz. Then "killall -SIGHUP cpuspeed" to put
it back in the default automatic mode (where it will kick the speed up
if the load stays high for maybe several seconds, IIRC).
Generally cpuspeed will do the right thing anyway - as load rises it
will speed up the CPU. Its got command line options to let you select
policy. See cpuspeed -h