No abstract

Motivated by the fast adoption of WebAssembly, we propose the first functional pipeline to support the superoptimization of Web-Assembly bytecode. Our pipeline works over LLVM and Souper. We evaluate our superoptimization pipeline with 12 programs from the Rosetta code project. Our pipeline improves the code section size of 8 out of 12 programs. We discuss the challenges faced in superoptimization of WebAssembly with two case studies.

No abstract

The comparison and alignment of runtime traces are essential, e.g., for semantic analysis or debugging. However, naive sequence alignment algorithms cannot address the needs of the modern web: (i) the bytecode generation process of V8 is not deterministic; (ii) bytecode traces are large.We present STRAC, a scalable and extensible tool tailored to compare bytecode traces generated by the V8 JavaScript engine. Given two V8 bytecode traces and a distance function between trace events, STRAC computes and provides the best alignment. The key insight is to split access between memory and disk. STRAC can identify semantically equivalent web pages and is capable of processing huge V8 bytecode traces whose order of magnitude matches today's web like https: //2019.splashcon.org, which generates approx. 150k of V8 bytecode instructions.

With energy efficiency one of the main challenges on the way towards ultrascale systems, there is a great need for access to high-quality energy consumption data. Such data would enable researchers and designers to pinpoint energy inefficiencies at all levels of the computing stack, from whole nodes down to critical regions of code. However, measurement capabilities are often missing, and significantly differ between platforms where they exist. A standard is yet to be established. To that end, this paper attempts an extensive survey of energy measurement tools currently available at both the hardware and software level, comparing their features with respect to energy monitoring.