author	 = {Tim Jammer},
	title	 = {{Energy usage analysis of HPC applications}},
	advisors	 = {Hermann Lenhart and Michael Kuhn},
	year	 = {2016},
	month	 = {12},
	school	 = {Universität Hamburg},
	type	 = {Bachelor's Thesis},
	abstract	 = {The importance of energy consumption of large scale computer systems will grow in the future, as it is not only a huge cost factor, it also leads to additional difficulty to cool those systems down. In order to gain experience on energy consumed by model simulation, I will analyze the energy consumed by the ECOHAM North Sea ecosystem model to deduct which parts of the application use the most energy. First the influence of the measurement of the energy usage on the application will be discussed. It is important to keep this influence in mind, as one wants to know about the energy usage of the unchanged application, so that the gathered insights are transferable to the application when it is running without the energy measurement. Furthermore my thesis will provide an overview on the energy which is needed by the different phases of the application. A focus is placed on the serial section where the output is written. The busy waiting implemented by the MPI implementation leads to an increased energy consumption. Without this busy waiting the application needs about 4 percent less energy. Therefore, I propose that the programmer of an MPI application should be able to choose which MPI calls should perform a non busy waiting.},