[mythtv-users] powernowd (et al) on SMP with Mythtv?

Michael Thome mthome at bbn.com
Fri Feb 23 14:39:03 UTC 2007

Whups - missed your reply...  I'm running 2.6.17 (ubuntu build)...  I'm 
holding off on later kernels because of the mess that is ivtv/dvb/v4l 
being in transition - had a *terrible* time finding a kernel+drivers 
combination where both pvr-150 and hd5500 would work at the same time.

Jarod Wilson wrote:
> Michael Thome wrote:
>> I'm having trouble getting powernowd (and other cpu scalers) to react 
>> appropriately to Myth's cpu loading patterns with my dual-core machine - 
>> I suspect I need to play around with parameters some more, but I thought 
>> I'd see if anyone else is happy with their settings.
>> The problem: watch live tv on a software-encoded tuner leads to high cpu 
>> utilization on one core (85-95%) but low on the other (10%).  powernowd 
>> leaves the clock rate at lowest setting, resulting in jerky motion on 
>> playback.  Similar situations can happing during DVD playing, HD 
>> playback, etc - one cpu is all out, the other is idle, average is around 
>> 50%.  Percept is great if I turn off powernowd, but then I'm always 
>> running at high clockrate.  Kernel-only on_demand seems to behave similarly.
>> My system is an Athlon 64 X2 4200+ (65W), Ubuntu Edgy
> What kernel? There have been a number of multi-core specific fixes to 
> the powernow-k8 code in recent kernels. The ondemand governor works 
> perfectly for me w/a kernel in a dual-core opteron system.

*Michael Thome*
BBN Technologies 10 Moulton St, Cambridge MA 02138 USA
phone: +1 617 873 1853

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