OpenCPN-low-energy

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Reducing energy consumption for OpenCPN

Research on OpenCPN

This is the first approach, basically we dive into the code to find parts of code executed too often that makes the program greedy on electrical power.

This research has been divided as follow :

• A diagram approach
• Modifying the delay for FrameTimer1 and TimerAIS to 20 seconds
• Measures to see the impact of long timers

Other

Abbreviations in the source code.

All timers in OpenCPN's source code

FrameTimer1

refreshes the current position of the boat and update AIS targets on the chart

COGTimer

updates the rotation angle of the chart in CourseUp mode(follow the boat course)

TCTimer

refreshes tide and current data on the chart

TimerAIS

updates the target list and computes CPA

TimerAISAudio

if alert is on, play alert sound

Initialization process

The OnInit() method, in chart1.cpp, starts FrameTimer1 and TimerAIS.

Building a distribution with susestudio.com

When it appeared that we couldn't improve opencpn consumption and that software and system parameters were not optimized, we decided to build our own distribution with Opencpn on-board. Two criterias were token into account:

• Installation must be as simple as Ubuntu, Fedora or OpenSuse.
• Maintain this distribution must be easy(don't have to look for dependencies, edit our own configuration files quickly)

Finally, we chose susestudio.com for it suited for our needs.

• How we made our distribution
• Download the distribution

Optimizing consumption

• Impact of Gmixer and Parcellite on consumption
• Screen management
• CPU tuning and pm-profiler
• Laptop mode tools
• Powertop advices

Hardware limitation

While we were consuming less power, we were wondering what is the less we could possibly reach ?
This page expose the hardware limits of our laptops.

Measure tools

This is the second way we used to measure the consumption. This page details the set up and the benefits of this new measure method.

At the end

At the end we have a perfectly working distribution with a lower consumption than the official OpenSUSE distribution. Here is a chart that compare a regular install of OpenSUSE 12.3 with LXDE and our distribution 0.2.1 on the ThinkPad laptop :

So, if your laptop isn't used for 5 minutes, you will consume something around 4,75 Watt instead of 10,7 Watt with the official OpenSUSE distribution (in average) ! The difference (5,95 Watt) isn't insignificant ! This result can't be generalized to any laptop/hardware.

You can find all the raw material here.

See also

• Github wiki
• Power consumption boot to sleep

All subpages

Pages with the prefix 'OpenCPN-low-energy' in the and 'Talk' namespaces:

:
OpenCPN-low-energy

• OpenCPN-low-energy/Building a distribution
• OpenCPN-low-energy/Hard drive halt
• OpenCPN-low-energy/OpenCPN-abbreviations
• OpenCPN-low-energy/Powertop advices
• OpenCPN-low-energy/Using datalogger.py
• OpenCPN-low-energy/cpu-tuning-and-pm-profiler
• OpenCPN-low-energy/diagram-approach
• OpenCPN-low-energy/first-measurements
• OpenCPN-low-energy/gmixer-and-parcellite
• OpenCPN-low-energy/hardware-limitations
• OpenCPN-low-energy/power-consumption-boot-to-sleep
• OpenCPN-low-energy/screen-brightness
• OpenCPN-low-energy/screen-management

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