Mozilla always looks to improve JavaScript performance in Firefox browser, you could’ve heard Tracemonkey, JagerMonkey JavaScript engines for Firefox in the past, Mozilla today has landed IonMonkey JavaScript JIT compiler for their SpiderMonkey engine on Firefox 18 nightly which on both Karan and Google V8 benchmarking tests performed well over Firefox 17 and Firefox 15.

David Anderson in Mozilla JavaScirpt blog says that “the old TraceMonkey*, and newer JägerMonkey, both had a fairly direct translation from JavaScript to machine code. There was no middle step. There was no way for the compilers to take a step back, look at the translation results, and optimize them further”.

IonMonkey now allows to

  • Translate JavaScript into Intermediate Representation (IR) ,
  • run various algorithms to Optimize the IR,
  • Translate the final IR to machine code.

IonMonkey doesn’t only improves JavaScirpt performance but also helps in future JavaScript compiler research for Mozilla.

IonMonkey performance in Benchmarking tests

On Karen benchmark “Firefox 17 runs in 2602ms, whereas Firefox 18 runs in 1921ms, making for roughly a 26% performance improvement”.

Firefox 18 Karen benchmark scrore

On Google v8 benchmark

  • Firefox 15 gets  score  of  8474
  • Firefox 17 score is 9511
  • Firefox 18 got  score of 10188.

Firefox 18 Google v8 score

From these scores we can say Firefox 18 runs 7% faster than Firefox 17 and  20% faster than Firefox 15. These benchmarks performed on Mac pro running Windows 7 Professional.

Have you seen any performance difference in Firefox 18 nightly with IonMonkey’s  addition? let us know in comments.