Re: v2.6.26-rc7: Negative powertop values

From: Vegard Nossum
Date: Sat Jun 21 2008 - 17:22:32 EST


On Sat, Jun 21, 2008 at 11:16 PM, Arjan van de Ven
<arjan@xxxxxxxxxxxxxxx> wrote:
> On Sat, 21 Jun 2008 21:16:37 +0200
> "Vegard Nossum" <vegard.nossum@xxxxxxxxx> wrote:
>> I was testing v2.6.26-rc7 by running lmbench and hotplug/-unplugging
>> CPUs and a few other programs at the same time. Powertop was showing a
>> negative number of wakeups/second and average C3 residency was
>> something really insane. Is there anything strange with this schedstat
>> file, or is there another file I should look at that can explain the
>> strange powertop numbers? Or maybe it's just an artifact of powertop
>> and this has nothing to do with the kernel?
>
> powertop doesn't assume you do cpu hotunplug (and the internal state
> goes wacky if you do).
>

Oh right :-) Are there any plans to support this?

> [I assume you know that doing a software unplug you burn more power
> than by leaving the cpu idle]

Well, yeah, this was purely to exercise the kernel a bit, IOW testing.
I guess this can be signed off as a non-kernel issue, then. Thanks for
the quick reply!


Vegard

--
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
-- E. W. Dijkstra, EWD1036
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