Addressing JavaScript JIT Engines Performance Quirks: A Crowdsourced Adaptive Compiler

Abstract

Abstract. JavaScript has long outpaced its original target applications, being used not only for coding complex web clients, but also web servers, game development and even desktop applications. The most appealing advantage of moving applications to JavaScript is its capability to run the same code in a large number of different devices. It is not surprising that many compilers target JavaScript as an intermediate language.However, writing optimizations and analyses passes for a compiler that emits JavaScript is challenging: a long time spent in optimizing the code in a certain way can be excellent for some browsers, but a futile effort for others. For example, we show that applying JavaScript code optimizations in a tablet with Windows 8 and Internet Explorer 11 increased performance by, on average, 5 times, while running in a desktop with Windows 7 and Firefox decreased performance by 20%. Such a scenario demands a radical new solution for the traditional compiler optimization flow. This paper proposes collecting web clients performance data to build a crowdsourced compiler flag suggestion system in the cloud that helps the compiler perform the appropriate optimizations for each client platform. Since this information comes from crowdsourcing rather than manual investigations, fruitless or harmful optimizations are automatically discarded. Our approach is based on live measurements done while clients use the application on real platforms, proposing a new paradigm on how optimizations are tested.

Using JavaScript and WebCL for numerical computations

“…also introduced JavaScript-specific optimization techniques for dealing with modularization constructs with ContextJS [32]. When it is used as a target, compilers need to be aware of the underlying implementation to extract maximum performance as shown by Auler et al [17]. In addition to performanceoriented contributions, the recent formalization of the semantics of the major parts of JavaScript standard [20] is paving the way for high-assurance translations of other languages to JavaScript with machine-checked implementation.…”

Guided just-in-time specialization

“…Given this importance, it comes as no surprise the upsurge of attention that JavaScript has received from the industry and the academia in recent years. Much of this attention is focused on the design and implementation of efficient Just-in-Time (JIT) compilers for this programming language [6,7,8,9]. One of the advantages of JIT compilation is specialization.…”

A survey of the use of crowdsourcing in software engineering

“…Auler et al [221] presented a crowdsourced adaptive complier for JavaScript code optimisation. A compiler flag recommendation system was built in the cloud, based on the application performance data gathered from web clients.…”

“…3) Program optimisation: More recently, crowdsourcing has been used to support compilation optimisation [221] and program synthesis [57].…”