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What makes WebAssembly fast?

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Re: What makes WebAssembly fast?

#21

Post by voxic11 »

amorphid wrote: post #12
astrodust wrote: post #2

It's both amusing and absurd that what was practically intended as Java's little helper, JavaScript, has grown up to be this thing that might actually replace Java entirely. How long until there's a really good JVM written in JavaScript of some form and embedded Java apps end up running in JavaScript for performance and security reasons? It'll be even more ridiculous and hilarious if the "j" in "jruby" ends up meanin…

Until JavaScript offers a robust concurrency abstraction, I don't see it completely replacing anything that is used for that purpose.

Async/await and promises are quite good concurrency abstractions.

Re: What makes WebAssembly fast?

#22

Post by Taek »

lacampbell wrote: post #20

I really hope web assembly takes off and becomes a thing wide implemented in all the major browsers. The web is such a fantastic application platform (despite its frequent misuse...), and removing the javascript performance tax will be huge.

JavaScript is not just a performance tax, it's also a language that is poorly suited to a great number of tasks which we would like to apply web browsers to today.

Not that it is all around terrible, but definitely much preferred if we can choose the best language for the job instead of being strictly stuck with JavaScript.

Re: What makes WebAssembly fast?

#23

Post by zeveb »

batmansmk wrote: post #6
astrodust wrote: post #2

It's both amusing and absurd that what was practically intended as Java's little helper, JavaScript, has grown up to be this thing that might actually replace Java entirely. How long until there's a really good JVM written in JavaScript of some form and embedded Java apps end up running in JavaScript for performance and security reasons? It'll be even more ridiculous and hilarious if the "j" in "jruby" ends up meanin…

Java and Javascript are related like Car and Carpet are similar. There was no historical connection between Java and JavaScript beyond renting the brand "Java" from Sun to make the language more credible.

Well, it's possible that if it hadn't been for Java JavaScript might have had a decent, parens-based syntax.

I still wonder what might have been if Eich had been allowed to write the Scheme system he had been hired to do. While I'm not a fan of Scheme by any means, it is approximately 281,757,423,024,353 better than JavaScript.

And Scheme's a great little language for implementing other languages. Imagine, we could have had transpiling years ahead of time. We might be using S-expressions instead of JSON. Heck, we might even have moved to an S-expression syntax for HTML & CSS by now.

Imagine, one syntax for everything (thanks to https://www.w3schools.com/js/tryit.asp?filename=tryjs_intro_... & https://www.w3schools.com/css/css_howto.asp for the examples):

    (html (head (title "Example")
            (style (body (background-color linen))
                   (h1 (color maroon)
                       (margin-left (px 40)))))
          (body
           (h1 "What can JavaScript do?")
           (p (@ (id "demo")) "JavaScript can " (em "change") " HTML content.")
           (button (@ (type "button")
                      (onclick (set! (inner-html (get-element-by-id document "demo"))
                                     "Hello JavaScript!")))
                   "Click me!")))
The world could have been so much better.

Re: What makes WebAssembly fast?

#24

Post by mstade »

dmarcos wrote: post #9
msoad wrote: post #3

I can totally see Qt a and .NET apps running on top WebAssembly. Imagine MS Word is running in your browser without them having to rewrite it in JS!

WebAssembly won't give you unlimited power. You will still have the browser sandboxing and security / privacy policies in place. Accessing to the local file system is for instance constrained in the browser for good reasons. WebAssembly apps will be able to do what Web APIs let any page do.

Is this universally true – i.e. baked in to the wasm spec – or is it just true in a browser environment? Consider things like NW.js[1] or Electron[2] – might we see cross platform apps being developed where all or parts of it are written in and compiled to wasm, then packaged up with a runtime and delivered as a "native" application for desktop, mobile, or whatever?

[1]: https://nwjs.io

[2]: https://electron.atom.io

Re: What makes WebAssembly fast?

#25

Post by 6nf »

lacampbell wrote: post #20

I really hope web assembly takes off and becomes a thing wide implemented in all the major browsers. The web is such a fantastic application platform (despite its frequent misuse...), and removing the javascript performance tax will be huge.

It looks very promising, most major players have experimental support for web assembly already.

Re: What makes WebAssembly fast?

#26

Post by nessus42 »

zeveb wrote: post #23
batmansmk wrote: post #6

Earlier quoted context omitted.

Java and Javascript are related like Car and Carpet are similar. There was no historical connection between Java and JavaScript beyond renting the brand "Java" from Sun to make the language more credible.

Well, it's possible that if it hadn't been for Java JavaScript might have had a decent, parens-based syntax. I still wonder what might have been if Eich had been allowed to write the Scheme system he had been hired to do. While I'm not a fan of Scheme by any means, it is approximately 281,757,423,024,353 better than JavaScript. And Scheme's a great little language for implementing other languages. Imagine, we could h…

I'm a HUGE fan of Scheme. And of Lisp, in general. But having seen in the "real world" how so many people are so adverse to Lisp's beautiful syntax, I'm pretty confident that JavaScript would never have caught on if it looked like Lisp rather than like C.

Re: What makes WebAssembly fast?

#28

Post by pmontra »

> At least for now, WebAssembly does not support garbage collection at all. Memory is managed manually (as it is in languages like C and C++). While this can make programming more difficult for the developer, it does also make performance more consistent.

Ouch, back to the 80s, early 90s. I think I'll stick with JavaScript at least until WebAssembly gets garbage collection. I might be wrong but I don't see many people writing SPAs in C++ for the extra speed (let's say, the JS layer acting like an X Server for the DOM, driven by a C++/WebAssembly application). Games, yes.

Furthermore JS has view source. WebAssembly has a text format [1] but it's really assembly. Hopefully there will be source maps [2].

[1] http://webassembly.org/docs/text-format/

[2] http://webassembly.org/docs/tooling/

Re: What makes WebAssembly fast?

#29

Post by zeveb »

nessus42 wrote: post #26
zeveb wrote: post #23

Earlier quoted context omitted.

Well, it's possible that if it hadn't been for Java JavaScript might have had a decent, parens-based syntax. I still wonder what might have been if Eich had been allowed to write the Scheme system he had been hired to do. While I'm not a fan of Scheme by any means, it is approximately 281,757,423,024,353 better than JavaScript. And Scheme's a great little language for implementing other languages. Imagine, we could h…

I'm a HUGE fan of Scheme. And of Lisp, in general. But having seen in the "real world" how so many people are so adverse to Lisp's beautiful syntax, I'm pretty confident that JavaScript would never have caught on if it looked like Lisp rather than like C.

They wouldn't have had a choice, though, just as folks don't have a choice with JavaScript.

I imagine that folks would have cottoned on to the advantage pretty quickly. And those that didn't … I guess they could have always become telephone cleaners or something:-)

Re: What makes WebAssembly fast?

#30

Post by Someone »

acqq wrote: post #16
chrisseaton wrote: post #8

Earlier quoted context omitted.

> Obviously, asm.js neither has JIT reoptimisation overhead Why does it never need to re-optimise the JITed code? I know WebAssembly and asm.js are more static than JS, but even very static languages like C benefit from speculative optimisations which may need to be reversed. For example asm.js and WebAssembly have branches don't they? Does the JIT always compile both branches even if one has never been taken in prac…

> For example asm.js and WebAssembly have branches don't they? Does the JIT always compile both branches even if one has never been taken in practice? WebAssembly is treated just like other "real binaries" produced for the "real" OS. Whatever survived the static optimizations while producing the binaries is converted, at the end, to the pure machine code, you don't "trace" it in run-time by the user. > even very stat…

I think that is left open to the implementation. _If_ an implementer thinks there is a benefit in doing so, he's free to do so.

In fact, that's similar to how a CPU runs "real binaries". Modern CPUs use _some_ runtime information to make code run faster. Examples include branch predictors and the recognition of stride lengths to move data into the cache before the instructions being executed need it.

That's only small bits, but it _is_ runtime information. I do not rule out that WebAssembly developers, similarly, will find hat there are ways to use runtime information that speed up WebAssembly code.

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