Breakout Session: V8 and future of web performance with JavaScript

V8 is the engine that runs Javascript in Chrome.  Important to make sure the engine matches the language as the language changes.  Specifically, V8 is a JIT (Just-in-time) compiler.  In general, the more optimization an engine performs, the faster the machine code it generates, but the longer the initial delay.  In general more optimizations an engine performs the more memory the engine consumes.  Tradeoffs in the engine - fast startup vs. peak performance and low memory vs. max optimization:


For example, web page has one line of code (e.g. foo(42);) an interpreter can perform that very quickly. Here's the example:

But if we know the function is going to be run 10,000 times you would want to take the capital cost of optimization up front and increase peak performance.

What if this is being run by a low-memory device (phone)?  Then we might want something like this:

Takeaway - code requires many different optimal translations depending on context (e.g. phone, server, IoT device, etc.).

With this in mind V8 has been looking at a completely new execution pipeline.  Here's the history:

TurboFan is an optimizing compiler.

Ignition is an interpreter and has a small memory footprint but faster startup.  It's integrated with TurboFan so that if a page is loaded many times it can pass it to TurboFan.  This allows for a lot of different configurations.

It's optimized for Node.js - this is server side language that imbeds the V8 engine.