On Wed, Jan 04, 2006 at 02:05:54PM -0500, Dave Jones wrote:
> On Wed, Jan 04, 2006 at 12:00:00PM +1100, Con Kolivas wrote:
> > +2.6.15-dynticks-060101.patch
> > +dynticks-disable_smp_config.patch
> > Latest version of the dynticks patch. This is proving stable and effective on
> > virtually all uniprocessor machines and will benefit systems that desire
> > power savings. SMP kernels (even on UP machines) still misbehave so this
> > config option is not available by default for this stable kernel.
>
> I've been curious for some time if this would actually show any measurable
> power savings. So I hooked up my laptop to a gizmo[1] that shows how much
> power is being sucked.
>
> both before, and after, it shows my laptop when idle is pulling 21W.
> So either the savings here are <1W (My device can't measure more accurately
> than a single watt), or this isn't actually buying us anything at all, or
> something needs tuning.
>
> Dave
I've done quite a bit of testing with dynticks and various c-state strategies.
On my thinkpad T42, dynticks can save about .5 W (as read from the ACPI battery
interface, but hey it's a good ballpark measurement). This is when compared to
250HZ and the stock ACPI c-state code. Both tests were running at the lowest
processor frequency (600 MHZ). The savings were much greater when running at
1.7 GHZ or when comparing to a HZ value of 1000. Also the advantage was closer
to 1 W when X was not running.
It might be possible to do even a little better. Currently, I'm developing a
new ACPI idle policy that tries to take advantage of the long time we may
be able to spend in a C3 state.
Thanks,
Adam
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
