Comparative efficiency of HEP codes across languages and architectures

Recently, interest in measuring and improving the energy (and carbon) efficiency of computation in HEP, and elsewhere, has grown significantly. Measurements have been, and continue to be, made of the efficiency of various computational architectures in standardised benchmarks, but those benchmarks tend to compare only implementations in single programming languages. Similarly, comparisons of the efficiency of various languages tend to focus on a single architecture, although it is the case that some abstractions in a given language can match specific architectural choices (in, say, memory ordering strictness) better than others. The existence of the JetReconstruction.jl project, implementing a subset of the FastJet C++ code’s functionality in performant Julia, allows us to usefully compare how the relative efficiencies of implementations in the two languages are influenced by the architecture they are executed on. We report on the results of comparing benchmarks on these codes, and others, on AMD64 and various aarch64 implementations, amongst others.