Fwd: XO 1.5 frequency scaling

[Tiago Marques]

> you're right.  there's nothing in powerd related to clocking.  powerd
> limits itself to managing the display, wlan on/off, and system suspend.
>

Seemed so, thanks.

>
>  > Did I miss some firmware or kernel update, as I can't load the c7
powersaver
>  > kernel module in a kernel I built myself.
>
> are you sure you're running the kernel you built?  (i.e., it, and
> whatever symlinks it needs to vmlinuz, need to be in /boot and
> /bootpart/boot.)

Yup, I'm not running it over Fedora but on Gentoo in an external HDD.
Some patch missing in the kernel perhaps?

Best regards,
Tiago

>
> paul
>
>  >
>  >
>  > >
>  > > ======================
>  > > I spent the day/night today working on getting our C states and P
states
>  > > enabled.
>  > >
>  > > The good news is that I got C4,C5 and frequency/voltage scaling (P
>  > > states) working.
>  > >
>  > > The bad news is that C5 causes memory corruption and P states don't
help
>  > > much.
>  > >
>  > > Enabling C4 seems to save us about 170mW in idle.
>  > >
>  >
>  > Any measurement on how low it goes in C4?
>  >
>  >
>  > >
>  > > C5 should save us a bit more but with it enabled the system won't
boot.
>  > > It gets all sorts of funky ext4 errors.  C5 turns off the L2 cache
and
>  > > the docs say you should flush before entering.  I suspect thats not
>  > > happening.
>  > >
>  > > P states currently don't seem to save us enough to be measured.  One
>  > > reason is that our core voltage is set by default to be very close to
>  > > the minimum.  Its at .796V and the minimum is .7V with scaling
enabled
>  > > (+ code hack) the minimum setting drops Vcore to .73V. Its supposed
to
>  > > go to .7 but the volt meter says otherwise.  60mV diff doesn't offer
a
>  > > whole lot of savings.
>  > >
>  >
>  > I see, I thought they could drop it even further.
>  >
>  >
>  > >
>  > > The CPU frequency slides between 400Mhz and 1GHz and you would think
>  > > that it would make a large difference but the meter says otherwise.
 How
>  > > can that be you ask?  The answer is because Linux issues a hlt when
>  > > idle.  If you run the test under OFW then you can create up to 1.5W
of
>  > > power difference by sliding the freq from min to max [1] and holding
the
>  > > Vcore constant.  But in idle not so much.  The processor already does
a
>  > > very good job of gating the clocks.
>  > >
>  > >
>  > Nice, kudos for VIA.
>  >
>  >
>  > > So this brings us back to what we already knew.  The big money on
power
>  > > savings is in our special sauce idle suspend.
>  > >
>  > > [1] Turns out you can overclock the processor.  Via lists the max
>  > > multiplier at 16x FSB (100Mhz) which is 1.6Ghz even though its listed
as
>  > > a max of 1Ghz. However if you continue to put values into the
multiplier
>  > > register the power draw continues to increase.  I stopped when the
>  > > system draw had hit 9W cause the XO on the power meter does not have
a
>  > > heat spreader and I didn't want to take the chance of burning it up.
>  > > =================
>  > >
>  >
>  > The heatspreader I can hack with a heatpipe and some coolers, I'm going
to
>  > do it anyway since it is already going to 85ºC in load. The speed is
of some
>  > use to me most of the time, I'm just worried that the VRM can't handle
the
>  > extra current.
>  >
>  > Best regards,
>  > Tiago
>  >
>  >
>  > >
>  > > --
>  > >
>  > > Richard A. Smith  <richard at laptop.org>
>  > > One Laptop per Child
>  > > _______________________________________________
>  > > Devel mailing list
>  > > Devel at lists.laptop.org
>  > > http://lists.laptop.org/listinfo/devel
>  > >
>  > part 2     text/plain                 129
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> =---------------------
>  paul fox, pgf at laptop.org
>
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