kannanvijayan

32 ms·

271.
by kannanvijayan 13y ago
Author here. The "regular JS scores" do REALLY well on several benchmarks (faster than native, even), for one primary reason: the transcendental math cache (which every JS engine uses). This is a very specific optimization that e
272.
by kannanvijayan 13y ago
The 5-10x difference mentioned is the difference in raw hardware speed between mobile CPUs and desktop CPUs, not a reference to JS speed vs native speed. JS speed as compared to native depends heavily on the nature of the code being execute
273.
by kannanvijayan 13y ago
That's not the point I was addressing. It's obviously true that mobile is slower than desktop by a factor of 5-10x. However, the author uses Sunspider as a metric to claim that "JS engines haven't really gotten all tha
274.
by kannanvijayan 13y ago
Disclaimer: I'm a JS JIT developer. The use of Sunspider performance to talk about JS application performance is unfortunate, and undermines a significant part of the argument made in the article. Sunspider is a great benchmark to use
275.
by kannanvijayan 14y ago
The Baseline JIT will have more of an impact on common web code than highly optimized JITs like Ion. Most web code executes for a few iterations, and runs for short periods of time. Baseline takes over from the interpreter far sooner than
276.
by kannanvijayan 14y ago
I'm not sure which builds you compared. Firefox 22 is currently in Aurora phase, and Firefox 21 is Beta. It does seem like there's been a regression in the aggregate scores. Thanks for bringing it up, though, that should be looked into.
277.
by kannanvijayan 14y ago
If a page goes into the back/forward cache, then its js code generally gets kept around. But we don't persistently store jitcode for a page, and I don't know of any JS engine that does.
278.
by kannanvijayan 14y ago
There will be separate jitcode generated for each page. It's hard to share this kind of code because during generation we often bake-in immediate pointers to various things (like global objects, etc.) into the generated jitcode. The jitcod
279.
JavaScript JITs: The Ins and Outs of Invalidation(blog.mozilla.org)
3 points by kannanvijayan 14y ago|0 comments