powernowd vs. ondemand governor

Matt Zimmerman mdz at canonical.com
Tue Feb 17 11:04:24 GMT 2009

On Mon, Feb 16, 2009 at 08:29:13PM +0000, Andy Whitcroft wrote:
> On Mon, Feb 16, 2009 at 02:58:01PM +0000, Matt Zimmerman wrote:
> > We currently ship powernowd in the desktop seed, its main purpose being to
> > load cpufreq modules set up the kernel's CPU frequency scaling governor.  If
> > (and only if) that fails, it starts up powernowd instead.  I'm not sure on
> > which platforms that's still needed, if any.
> > 
> > Is this still an appropriate default?  Aren't the necessary modules loaded
> > automatically now?  Would it be a better idea to set the default to ondemand
> > in the kernel and drop powernowd altogether?
> When this came up at UDS the response was that booting was faster with
> the mode set to performance.  Thus it is set to performance by default,
> and then changed to ondemand once boot is complete.  Perhaps the
> bootchart capable amongst us could re-confirm that.

My understanding is that it should be set to 'ondemand' by powernowd.early,
which runs fairly early in runlevel 2.

I occasionally encounter a situation where it ends up left at 'performance',


I just noticed this on a different system yesterday, which is what led me to
wonder whether this setup could be simplified.

 - mdz

More information about the ubuntu-devel mailing list