The SpiderMonkey (JS) team has been working on a significant update to
our JITs called WarpBuilder (or just Warp) [0,1]. Before we enable
Warp by default in Nightly (hopefully next cycle in 83) we need your
help dogfooding it.
Warp improves performance by reducing the amount of internal type
information that is tracked, optimizing for a broader spectrum of
cases, and by leveraging the same CacheIR optimizations used by last
year’s BaselineInterpreter work . As a result, Warp has a much
simpler design and improves responsiveness and page load performance
significantly (we're seeing 5-15% improvements on many visual metrics
tests). Speedometer is about 10% faster with Warp. The JS engine also
uses less memory when Warp is enabled.
To enable Warp in Nightly:
1. Update to a recent Nightly
3. Restart the browser
We're especially interested in stability issues and real-world
performance problems. Warp is currently slower on various synthetic JS
benchmarks such as Octane (which we will continue investigating in the
coming months) but should perform well on web content.
If you find any issues, please file bugs blocking:
If you notice any improvements, we'd love to hear about those too.
Finally, we want to thank our amazing contributors André Bargull and
Tom Schuster for their help implementing and porting many
Turning Warp on is only our first step, and we expect to see a lot of
new optimization work over the next year as we build on this. We are
excited for what the future holds here.
The Warp team
 WarpBuilder still utilizes the backend of IonMonkey so we don't
feel it has earned the WarpMonkey name just yet.