Dogfooding Warp

Jan de Mooij jdemooij at
Thu Sep 24 12:56:57 UTC 2020

Warp is now enabled by default on Nightly, after positive feedback
from users dogfooding it [0,1].

Here are just a few of the Talos/Raptor graphs showing improvements
when Warp landed:

- 20% on Win64 GDocs loadtime:
- 13% on Android Reddit SpeedIndex:
- 18% on pdfpaint:
- 8% on tp6 JS memory:
- 8% on damp (devtools perf):

Please let us know if you notice any improvements or regressions.

The Warp team


On Tue, Sep 15, 2020 at 2:57 PM Jan de Mooij <jdemooij at> wrote:
> Hi all,
> 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 [2]. 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
> 2. Go to about:config and set the "javascript.options.warp" pref to true
> 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
> optimizations.
> 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.
> Thanks!
> The Warp team
> [0] WarpBuilder still utilizes the backend of IonMonkey so we don't
> feel it has earned the WarpMonkey name just yet.
> [1]
> [2]

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