OpenCPN-low-energy/first-measurements
First measurements
To know if our breakthrough were efficients in term of energy consumption, we needed to measure the improvements.
Measure method
We used the Yocto-watt watt-meter with a php script to retrieve the logs from the measured laptop. Our firsts measures had this set up :
You can see that we are obliged to use the VirtualHub program to control remotely the Yocto-watt module. To obtain the logs from the measuring module, we modified an example file of Yocto-watt, thus, we used PHP (and the library) with Apache2 to execute our data logger version. You can find the datalogger file here.
We used two HP EliteBook 2570p laptop to do the measures with two graphical environment of OpenSUSE 12.3, LXDE and KDE. You can click on the values to get the associate measure report.
| LXDE | KDE | |
|---|---|---|
| System only | 12.654 | 12.621 |
| OpenCPN untouched | 12.831 | 12.6 |
| OpenCPN modified | 12.848 | 12.815 |
The difference of power consumption are explainable, the measures above didn't only look the power needed by OpenCPN but by the whole laptop. In order to get more accurate and that specifically target OpenCPN, we used powertop. We noticed that our modified version of OpenCPN (the one with timer modifications) consumed just a little bit less than the original version. If you look close at the both powertop reports, you will notice that the operating system's applications are taking the "space" left by the OpenCPN timers we have modified.
Powertop reports :