Power consumption ARM vs. x86 (was Re: Creating a cross compiler from ARM to x86)

[Stefan Ruppert <sr at myarm dot com>]

Am 05.07.2014 19:59, schrieb Jason Smith:
> I am trying to build a cross compiler on a BeagleBone Black to compile
> from ARM to x86. The intent of this is to use the low power consuming
> BeagleBone Black that I had on hand as a build server. It can already
> compile for windows through mingw-w64, but I need it to also compile the
> code for Linux x86 systems.

Hi Jason,

do you have measured power consumption of an x86 based-system and
compared it to the power consumption of your BeagleBone?

I have measured the power consumption using Fritzbox 7390 and Fritz Dect
200, thus its the consumption of the complete system.

We have a ARM-based quad-core Utilite Pro (http://utilite-computer.com/)
(Freescale i.MX6 quad-core Cortex-A9 @1GHz running ubunutu 12.04) system
consuming around 5 Watt in idle mode and around 8 Watt average when 3
cores are active. Our quad-core Xeon x86 64-bit (Xeon(R) CPU E3-1245 v3
@ 3.40GHz, limited to 2.9GHz running debian 7.5) system uses 20 Watt in
idle and around 40 Watt average when 3 cores are active.

An build of our MyARM software needs 5 minutes on the xeon-system
(building totally in RAM ;-) and 19 minutes on the ARM-based system.

Now roughly calculating power consumption:

Xeon-based: 40W * ( 5/60)h = ~3.3Wh
ARM-based:   8W * (19/60)h = ~2.5Wh

Now measuring build time and power consumption when only a single core
is used:

Xeon-based: 11.5 minutes build time and around 34 Watt average
ARM-based   40.5 minutes build time and around  7 Watt average

Resulting in the following power consumption:

Xeon-based: 34W * (11,5/60)h = ~6.5Wh
ARM-based:   7W * (40,5/60)h = ~4.7Wh

With 4 cores active:

Xeon-based: 44W * (4,25/60)h = ~3,11Wh
ARM-based:   9W * (17/60)h   = ~2,55Wh

Thus using more cores reduces overall power consumption and our
ARM-based system uses around 30% less power. But our Xeon-Server is a
VM-Server serving up-to 18 different VMs with different operating systems...

Regards,
Stefan

--
MyARM measuring response time, performance and more ...