Mobile Processors for Scientific Use: A Critical Analysis of the Impact of Design Trends on Performance and Energy Use in Scientific Applications

The technical and market challenges that central processing unit (CPU) designers have experienced in the last decade or so has changed CPU's drastically. There is a focus on energy-efficient multi-core designs that was prompted by the rise of smartphones and the demise of Moore's Law. Examination of CPU specifications and the associated marketing statements suggest that the design focus has been on making the batteries of mobile devices last while intending that multi-core designs should replace Moore's law. This research set out to measure what the real effect of these developments has been on the performance and energy use of the devices that we use every day. We focus on scientific applications, and especially how processors intended for mobile devices compare to those intended for desktop devices in that environment. The research and the test results show that successive generations of the devices that we have tested not only use more dynamic energy but leave users with desktop devices that in actual use, are slower. The results also show that while there have been incremental improvements in performance for the mobile devices, that improvement came at the cost of increased energy use. We further show that published performance specifications should be evaluated in the context of how well the current generation of software can exploit that potential. Our tests further demonstrate a number of related issues, such as the effect of CPU governors, cache memory and the operating system on performance. The influence of general-purpose computing on graphics processing units (GPGPU) on processing speed and energy use is also tested. We use the measured energy consumption of the devices to extend the Koomey's Law graph and show that the energy efficiency trend significantly flattens with the ending of Moore's Law. The data also shows that while the energy use at idle has significantly decreased over the last decade, dynamic energy use did not follow the same trend.

Jaar van publicatie:2022

Toegankelijkheid:Embargoed