FC6 core duo and cpuspeed

[Christian Menzel]

No, this is not the i586 problem :-)

I just upgraded my ThinkPad T60p to FC6 and I'm under the impression
that the core duo isn't handled as good as in FC5.
When starting cpuspeed it doesn't go into daemon mode but instead loads
the cpufreq_ondemand module. The CPU scaling applets can be loaded in
the tray and configured for CPU0 and CPU1 but changing the frequency for
one CPU results in a parallel change for the other.
This is also the case when the system is under load, the applets always
show the same freq for both cores. This behavior is different from the
behavior in FC5, where sometimes only one CPU was under load.
As a side effect, I think the fan is running more often and at a higher
speed as before.

Is there something I must configure, or should I build a custom SMP
kernel?

Regards
Chris

[Mikkel]

Christian Menzel wrote:
>  No, this is not the i586 problem :-)
>  
>  I just upgraded my ThinkPad T60p to FC6 and I'm under the impression
>  that the core duo isn't handled as good as in FC5.
>  When starting cpuspeed it doesn't go into daemon mode but instead loads
>  the cpufreq_ondemand module. The CPU scaling applets can be loaded in
>  the tray and configured for CPU0 and CPU1 but changing the frequency for
>  one CPU results in a parallel change for the other.
>  This is also the case when the system is under load, the applets always
>  show the same freq for both cores. This behavior is different from the
>  behavior in FC5, where sometimes only one CPU was under load.
>  As a side effect, I think the fan is running more often and at a higher
>  speed as before.
>  
>  Is there something I must configure, or should I build a custom SMP
>  kernel?
>  
>  Regards
>  Chris
>  
>   
There is no way to set the speeds of the CPU's individually. This is
because of the way the CPU chip is designed. I don't have the link
handy, but I think it was in a CNET review that I ran across it the
first time. The 2 CPUs are on the same chip, and share the same
clock and L2 cache. They always run at the same speed, even if the
second CPU is not doing anything. Also, you can not put just one CPU
to sleep. (Depending on what definition of CPU you use, I guess you
could consider it one CPU with 2 cores or processing units...)

Mikkel
-- 

  Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!

[Dave Jones]

On Fri, Nov 03, 2006 at 11:28:07AM +0100, Christian Menzel wrote:
>  No, this is not the i586 problem :-)
>  
>  I just upgraded my ThinkPad T60p to FC6 and I'm under the impression
>  that the core duo isn't handled as good as in FC5.
>  When starting cpuspeed it doesn't go into daemon mode but instead loads
>  the cpufreq_ondemand module. The CPU scaling applets can be loaded in
>  the tray and configured for CPU0 and CPU1 but changing the frequency for
>  one CPU results in a parallel change for the other. 
The power domain is per socket, not per core.
Current Core CPUs cannot change voltage on a per-core basis.

>  This is also the case when the system is under load, the applets
> always
>  show the same freq for both cores. This behavior is different from the
>  behavior in FC5, where sometimes only one CPU was under load. 
the cpuspeed daemon as shipped doesn't support dual core, and would
report inaccurate states.
This is why it's now using ondemand.

	Dave

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

[Christian Menzel]

On Fr, 2006-11-03 at 10:33 -0500, Dave Jones wrote:
>  The power domain is per socket, not per core.
>  Current Core CPUs cannot change voltage on a per-core basis.
>  
>   > This is also the case when the system is under load, the applets always
>   > show the same freq for both cores. This behavior is different from the
>   > behavior in FC5, where sometimes only one CPU was under load.
>  
>  the cpuspeed daemon as shipped doesn't support dual core, and would
>  report inaccurate states.
>  This is why it's now using ondemand.
>   
OK, then please excuse my ignorance.

I guess that means the display in FC5 was simply wrong. 
Too bad, I liked having two CPU-freq-apps in the panel :-)

Thanks
Chris