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Subject: Re: [PATCH] Dynamic tick for x86 version 050610-1
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: hugang@soulinfo.com
Cc: Tony Lindgren <tony@atomide.com>, linux-kernel@vger.kernel.org,
       "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
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Date: Tue, 19 Jul 2005 23:51:54 +1000
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On Tue, 2005-07-19 at 14:51 +0800, hugang@soulinfo.com wrote:
> On Sat, Jun 18, 2005 at 04:30:32PM +1000, Benjamin Herrenschmidt wrote:
> > 
> > > I'm try to port it powerpc, Here is a patch.
> > > 
> > >  Port Dynamic Tick Timer to new platform is easy. :)
> > >   1) Find the reprogram timer interface.
> > >   2) do a hook in the idle function.
> > > 
> > > That worked on my PowerBookG4 12'.
> > 
> > Did you get a measurable gain on power consumption ?
> > 
> > Last time I toyed with this, I didn't.
> 
> Today I do a measurable about it. 
> 
> First I using 2.6.12 without dynamic enable and unplug the AC power,
> I check the /proc/pmu/battery_0, like this.
> --
>  flags      : 00000011
>  charge     : 907
>  max_charge : 2863
>  current    : -987
>  voltage    : 10950
>  time rem.  : 3600
> --
> I only intresting with current, that show the system power load. 
> 
> When I enable dynamic, The current can low at -900.

The numbers are repeatable ? I mean, if you actually let it settle down
in both cases ? Also, you should be careful about "parasites" in the
measurement, like pbbuttons dimming the backlight, the hard disk going
to sleep etc...

>>From your numbers you get something like 10% improvement, which isn't
too bad.

Ben.