Re: [RFC PATCH 2/3] sched: power aware load balance,

From: Andrew Morton
Date: Tue Nov 06 2012 - 14:51:06 EST


On Tue, 6 Nov 2012 21:09:58 +0800
Alex Shi <alex.shi@xxxxxxxxx> wrote:

> $for ((i=0; i < I; i++)) ; do while true; do : ; done & done
>
> Checking the power consuming with a powermeter on the NHM EP.
> powersaving performance
> I = 2 148w 160w
> I = 4 175w 181w
> I = 8 207w 224w
> I = 16 324w 324w
>
> On a SNB laptop(4 cores *HT)
> powersaving performance
> I = 2 28w 35w
> I = 4 38w 52w
> I = 6 44w 54w
> I = 8 56w 56w
>
> On the SNB EP machine, when I = 16, power saved more than 100 Watts.

Confused. According to the above table, at I=16 the EP machine saved 0
watts. Typo in the data?


Also, that's a pretty narrow test - it's doing fork and exec at very
high frequency and things such as task placement decisions at process
startup might be affecting the results. Also, the load will be quite
kernel-intensive, as opposed to the more typical userspace-intensive
loads.

So, please run a broader set of tests so we can see the effects?
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