Bits Nets Energy

Power estimation of three real-life application scenarios for Bits-Nets-Energy research

In context of the Bits-Nets-Energy research performed by Green IT Amsterdam, UvA, SARA, TNO, SURFnet, and SURF funded by AgentschapNL, Green IT Amsterdam collaborated with the SEFLab to construct three real-life application scenarios and compare them on power consumption.

This allowed us to survey the energy usage characteristics of processors, memory, hard disks and other compo­nents when a server is asked to transfer data, to perform calculation-heavy operations, and to provide a remote application to an end user. The measurements were compared to the idle state of the server, and therefore show the additional power consumption resulting from a request for service.

In the ‘idle’ situation, the system uses 150.4 W of power. The breakdown over the components was as follows:

Server load

CPU 1

CPU 2

MB

MEM

HDD1

HDD2

FANS

150.4

 23.4

23.0

 26.6

 24.5

9.18

 2.69

 3.32

Table 1: Idle power usage (in W)

Scenario 1: data retrieval

The first scenario inspected was the transfer of data. A file was downloaded from the server using the FTP proto­col. The throughput was 7.8 Mbit/s, resulting in a download of a 1 GB file in 131 seconds. The server load increased by only 4% compared to the idle situation, mainly because CPU power consumption increased (11%). This is not significant, as the FTP server was running additional log­ging functionality.

Server load

CPU 1

CPU 2

MB

MEM

HDD1

HDD2

FANS

155.9

26.2

24.3

26.7

25.3

9.14

2.69

 3.32

Table 2: data transfer power usage (in W)

Scenario 2: interactive software

The second scenario consisted of running an application for the remote control of a desktop (Ultr@VNC), with a video file running on the server that was being viewed at a connected client computer. Playing this movie for the client increased the server’s power consumption by 35%. This was mainly the result of an increase in CPU power consumption by 91%.

Server load

CPU 1

CPU 2

MB

MEM

HDD1

HDD2

FANS

204.1

 47.7

42.9

 26.9

 26.7

8.83

 2.64

 3.26

Table 3: remote video playback power usage (in W)

Scenario 3: CPU-intensive processing

The third scenario was an illustration of CPU-intensive processing: the re-encoding of a video file in a different for­mat. By re-encoding an MP4 file to DivX, we simulated a CPU-intensive task. Re-encoding resulted in a 40% increase in power consumption as compared to the idle state, and a 110% increase in power consumption resulting from the CPUs.

Server load

CPU 1

CPU 2

MB

MEM

HDD1

HDD2

FANS

209.2

52.1

46.1

 26.8

 24.7

9.24

 2.68

 3.33

Table 4: processing re-encoding a video file (in W)


Partner
: Green IT Amsterdam

Period: April 2013 – May 2013

Contact: Bo Merkus, b.merkus@hva.nl

More info: http://www.surf.nl/nl/publicaties/Pages/TransportingBitsorTransportingEnergy.aspx

Result: Transporting Bits or Transporting Energy – does it matter – May2013.pdf