Dogfooding Warp

Jan de Mooij jdemooij at mozilla.com
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: https://mzl.la/3cp6dAs
- 13% on Android Reddit SpeedIndex: https://mzl.la/2RUWdp8
- 18% on pdfpaint: https://mzl.la/2HtXb9W
- 8% on tp6 JS memory: https://mzl.la/3j2VwGb
- 8% on damp (devtools perf): https://mzl.la/3kLbhSM

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

Thanks,
The Warp team

[0] https://www.reddit.com/r/firefox/comments/itib6s/dogfooding_warp_on_nightly_new_js_jit_engine/
[1] https://www.reddit.com/r/firefox/comments/iy2036/nightly_is_finally_feeling_as_fast_as_chromium/

On Tue, Sep 15, 2020 at 2:57 PM Jan de Mooij <jdemooij at mozilla.com> 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:
>
> https://bugzilla.mozilla.org/show_bug.cgi?id=1613592
>
> 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] https://bugzilla.mozilla.org/show_bug.cgi?id=1613592
> [2] https://hacks.mozilla.org/2019/08/the-baseline-interpreter-a-faster-js-interpreter-in-firefox-70/


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