Xen users - Apr 2006 - XEN and Frequency scaling PowerNow or Speedstep

Hello !

I installed xen-unstable with a custom 2.6.16 kernel on my "server" at
home (Athlon64 3200+ Venice Type, OpenSuse 10.0). Before using XEN my
system was sucessfully scaling CPU Frequency. The CPU supports 3
Frequencies and voltages.

from dmesg when loading module powernow-k8
Apr  8 00:30:02 parzival kernel: powernow-k8:    0 : fid 0xc (2000 MHz),
vid 0x6 (1400 mV)
Apr  8 00:30:02 parzival kernel: powernow-k8:    1 : fid 0xa (1800 MHz),
vid 0x8 (1350 mV)
Apr  8 00:30:02 parzival kernel: powernow-k8:    2 : fid 0x2 (1000 MHz),
vid 0x12 (1100 mV)

This led to a really "cool and quiet" system since the Mainboard (ASUS
A8N-E) is also controlling the CPU-fan depending on temperature. This
system is running 24/7 and is in our living room so the system
components were carefully chosen to be quiet.

Now under XEN this doesn''t work anymore. Is this a missing feature or a
bug ? My message log fills up with:

Apr  8 00:30:03 parzival kernel: powernow-k8: fid trans failed, fid 0x2,
curr 0xc
Apr  8 00:30:03 parzival kernel: powernow-k8: transition frequency failed
Apr  8 00:30:05 parzival kernel: powernow-k8: fid trans failed, fid 0x2,
curr 0xc
Apr  8 00:30:05 parzival kernel: powernow-k8: transition frequency failed

Of course my home system is not that important for the XEN roadmap but
even the professional CPU''s get powersaving and frequency-scaling
functions like EIST these days to keep crowded server racks cool.

If XEN is made for efficency this is an important feature...

Any hints ?

-- 
__________________________________________________

Ralf Schenk
fon (02 41) 9 91 21-0
fax (02 41) 9 91 21-59
rs@databay.de

Databay AG
Hüttenstraße 7
D-52068 Aachen
www.databay.de

Databay - einfach machen.

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On Sat, 2006-04-08 at 00:44 +0200, Ralf Schenk wrote:
> I installed xen-unstable with a custom 2.6.16 kernel on my
"server" at
> home (Athlon64 3200+ Venice Type, OpenSuse 10.0). Before using XEN my
> system was sucessfully scaling CPU Frequency. The CPU supports 3
> Frequencies and voltages.
I''m pretty new to Xen myself, but it looks like a patch was recently
submitted to add powernow-k8 support:

http://article.gmane.org/gmane.comp.emulators.xen.devel/22282

No idea if it was accepted and made it in to 3.0.2.

-- 
Stuart Jansen <sjansen@gurulabs.com>
Guru Labs, L.C.


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Stuart Jansen schrieb:
> On Sat, 2006-04-08 at 00:44 +0200, Ralf Schenk wrote:
>> I installed xen-unstable with a custom 2.6.16 kernel on my
"server" at
>> home (Athlon64 3200+ Venice Type, OpenSuse 10.0). Before using XEN my
>> system was sucessfully scaling CPU Frequency. The CPU supports 3
>> Frequencies and voltages.
> 
> I''m pretty new to Xen myself, but it looks like a patch was
recently
> submitted to add powernow-k8 support:
> 
> http://article.gmane.org/gmane.comp.emulators.xen.devel/22282
> 
> No idea if it was accepted and made it in to 3.0.2.
> 
Hello !

I tried it instantly - It works for me ! I''ll see if my system stays
stable in the next days.
Thanks a lot.

For people using mobile cpus this would be also an interesting example
for implementing this into other kernelmodules (i.e. speedstep) to ake
them work with XEN.

-- 
__________________________________________________

Ralf Schenk
fon (02 41) 9 91 21-0
fax (02 41) 9 91 21-59
rs@databay.de

Databay AG
Hüttenstraße 7
D-52068 Aachen
www.databay.de

Databay - einfach machen.

_________________________________________________



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