Selection of the type of cooling for an overclocked Raspberry Pi 4B minicomputer processor operating at maximum load conditions

The Raspberry Pi is a computer platform that is widely used in education, has a very large community and extensive documentation. Therefore, it can be a good and cheap alternative to a traditional computer, a TV streaming device or a console for less demanding games. In the case of observing a lower efficiency of the microcomputer, one of many possibilities of improvement, which this device offers is overclocking the processor. It is associated with a proper selection of parameters (voltage, clocking) and software in order to achieve the highest possible performance of the dedicated Raspbian system. However, increasing the work efficiency causes the temperature rise up to the limit values. Therefore, an appropriate, i.e. effective, kind of cooling should be applied. Taking all these circumstances into account, an experiment was developed in which temperature measurements were taken during the maximum processor load on all cores at the clock setting that enabled reaching the highest performance. During the research three cases were considered: without the use of cooling, with passive cooling and with active cooling. The results showed that only the use of active cooling clearly improves the operating conditions of the device, due to lowering the temperature by about 16°C compared to the situation without cooling or with the use of a passive radiator.

Computing the Price of Anarchy in Processor Load Balancing Game with Linear Delays

This paper considers a generalization of the processor load balancing game also known as KP-model. A linear delay of a processor may depend on not only its load but on loads of other processors. Players choose processors of different speeds to run their jobs striving to minimize job's delay, i.e., the job completion time on a chosen processor. The social cost is the maximum delay over all processors. We propose a computing algorithm of the exact PoA value which can be applied to estimate the POA visually if its exact analytical expression is not obtained yet or it is rather complicated to figure out its formula.

Comparison of selected network communication methods on the Android platform

This paper is devoted to comparing three communication methods between mobile applications and servers. The analysis encompassed the results of six tests conducted using HTTP and HTTPS protocols, and server-socket technology. All sending times of data with various sizes between the client application and the server, and the impact of this operation on the processor load and battery use, were evaluated. The experiments consisted of sending and receiving a form, sending and receiving a large photo, and ensuring continuous communication to assess device use. To perform the analyses, an Android application was created to support the researched technology, while the server side was composed of programs written in Java, running on a Tomcat server. The conducted research made it possible to establish the best solution, which is server-socket technology.

Load Balancing for Parallel Multiphase Flow Simulation

This paper presents a scalable dynamic load balancing scheme for a parallel front-tracking method based multiphase flow simulation. In this simulation employing both Lagrangian and Eulerian grids, processes operating on Lagrangian grid are susceptible to load imbalance due to moving Lagrangian grid points (bubbles) and load distribution based on spatial location of bubbles. To load balance these processes, we distribute load keeping in view both current processor load distribution and bubble spatial locality and remap interprocess communication. The result is a uniform processor load distribution and predictable and less expensive communication scheme. Scalability studies on the Hazel Hen supercomputer demonstrate excellent scaling with exponential savings in execution time as the problem size becomes increasingly large. While moderate speedup is observed for strong scaling, speedup of up to 30% is achieved over nonload-balanced version when simulating 13824 bubbles on 4096 cores for weak scaling studies.