8 ms·

I generally find Safari’s performance better than other browsers. Also, every mainstream JS runtime is multithreaded. There are limitations on what can be share

I generally find Safari’s performance better than other browsers. Also, every mainstream JS runtime is multithreaded. There are limitations on what can be shared between threads, but you can optimize a lot despite those limitations (including using WASM on the web, and native extensions/FFI on Node/Deno).

halpert 5y ago
On iOS, the perf of Safari is definitely better than every other browser, because every other browser is mandated to use WkWebView by Apple. They aren’t allowed to implement their own engine. Of course Apple isn’t subject to the same restriction.
- amelius 5y ago
  Soon, other browsers can simply run themselves inside WASM which then runs inside a WkWebView :)
- jacobolus 5y ago
  On a Mac, Safari Javascript generally outperforms Chrome and Firefox (other browsing tasks are also generally better performing), but there are some workloads where Safari turns out slower, especially when the developer has put a lot of work into Chrome-specific optimization. Safari also generally uses a lot less memory and CPU for the same websites. Chrome in particular burns through my battery very quickly, and is basically completely incapable of keeping up with my browser use style (it just crashes when I try to open a few hundred tabs). Presumably nobody with authority at Google is a heavy laptop web-user or prioritizes client-side resource use: Google’s websites are also among the biggest browser resource hogs, even when sitting idle in a background tab. Safari often takes a couple years longer than other browsers to implement cutting-edge features. This seems to me like a perfectly reasonable design decision; some web developers love complaining about it though, and some sites that were only developed against the most recent versions of Chrome don’t work correctly in Safari.
Uehreka 5y ago
In my experience, if the thing I’m working on runs in Safari, it’s buttery smooth. And if it doesn’t run, it completely shits the bed. Stuff like “we don’t support that way of doing shadows in SVG, so rather than simply not implement that property, we’ve turned your entire SVG element black”.
johncolanduoni 5y ago
Every mainstream JS runtime has some sort of background garbage collection and parsing/compilation, but for any execution that has to interact with JavaScript heap or stack state you’re still in single threaded territory. SharedArrayBuffer can help if you’re willing to give up on JavaScript objects entirely, and for WebAssembly this is less of a burden, but that’s not going to help you perform rendering on most web apps concurrently. JSCore goes a little bit further and can run javascript in the same runtime instance on multiple threads with some significant limitations, but this isn’t exposed to developers on Safari.
- eyelidlessness 5y ago
  It really depends on your use case and on how you design for threads. Quite a lot of data types can be sent by postMessage, and a decent amount of them are transferable. If your use case doesn’t require passing around functions (and if you can’t find a way to work around that), many workloads which would benefit from multithreading in another language will likely similarly benefit from JS threads (Web Workers, Node’s Worker Threads, etc). The biggest determining factor at that point is whether the overhead of instantiating them, and of message passing, is worth it. (And the latter is often a lot less than people realize; in my experience it’s almost universally faster than crossing a WASM/FFI-type of boundary.)
  - johncolanduoni 5y ago
    On what engine have you seen postmessage be faster than a WASM/JS boundary? It’s at least an order of magnitude slower on Chrome/V8, even when a call needs to pass significant strings into WASM (microseconds vs hundreds of ns). It’s also worth noting that postmessage is itself an FFI boundary that requires a JS to C++ transition on every engine I’m aware of.
    - eyelidlessness 5y ago
      I’ve seen in on Node 16 (also V8) trying both purpose-built and custom bindings to libraries built in Rust, C, C++ and Go. All of the purpose built libraries acknowledge there’s an overhead to cross the native/WASM boundary. In my experience, measuring extensively, postMessage with native runtime objects outperforms any other ser/de solution that works with JS values.

halpert 5y ago

On iOS, the perf of Safari is definitely better than every other browser, because every other browser is mandated to use WkWebView by Apple. They aren’t allowed to implement their own engine. Of course Apple isn’t subject to the same restriction.

amelius 5y ago
Soon, other browsers can simply run themselves inside WASM which then runs inside a WkWebView :)
jacobolus 5y ago
On a Mac, Safari Javascript generally outperforms Chrome and Firefox (other browsing tasks are also generally better performing), but there are some workloads where Safari turns out slower, especially when the developer has put a lot of work into Chrome-specific optimization. Safari also generally uses a lot less memory and CPU for the same websites. Chrome in particular burns through my battery very quickly, and is basically completely incapable of keeping up with my browser use style (it just crashes when I try to open a few hundred tabs). Presumably nobody with authority at Google is a heavy laptop web-user or prioritizes client-side resource use: Google’s websites are also among the biggest browser resource hogs, even when sitting idle in a background tab. Safari often takes a couple years longer than other browsers to implement cutting-edge features. This seems to me like a perfectly reasonable design decision; some web developers love complaining about it though, and some sites that were only developed against the most recent versions of Chrome don’t work correctly in Safari.

Uehreka 5y ago

In my experience, if the thing I’m working on runs in Safari, it’s buttery smooth. And if it doesn’t run, it completely shits the bed. Stuff like “we don’t support that way of doing shadows in SVG, so rather than simply not implement that property, we’ve turned your entire SVG element black”.

johncolanduoni 5y ago

Every mainstream JS runtime has some sort of background garbage collection and parsing/compilation, but for any execution that has to interact with JavaScript heap or stack state you’re still in single threaded territory. SharedArrayBuffer can help if you’re willing to give up on JavaScript objects entirely, and for WebAssembly this is less of a burden, but that’s not going to help you perform rendering on most web apps concurrently. JSCore goes a little bit further and can run javascript in the same runtime instance on multiple threads with some significant limitations, but this isn’t exposed to developers on Safari.

eyelidlessness 5y ago
It really depends on your use case and on how you design for threads. Quite a lot of data types can be sent by postMessage, and a decent amount of them are transferable. If your use case doesn’t require passing around functions (and if you can’t find a way to work around that), many workloads which would benefit from multithreading in another language will likely similarly benefit from JS threads (Web Workers, Node’s Worker Threads, etc). The biggest determining factor at that point is whether the overhead of instantiating them, and of message passing, is worth it. (And the latter is often a lot less than people realize; in my experience it’s almost universally faster than crossing a WASM/FFI-type of boundary.)
- johncolanduoni 5y ago
  On what engine have you seen postmessage be faster than a WASM/JS boundary? It’s at least an order of magnitude slower on Chrome/V8, even when a call needs to pass significant strings into WASM (microseconds vs hundreds of ns). It’s also worth noting that postmessage is itself an FFI boundary that requires a JS to C++ transition on every engine I’m aware of.
  - eyelidlessness 5y ago
    I’ve seen in on Node 16 (also V8) trying both purpose-built and custom bindings to libraries built in Rust, C, C++ and Go. All of the purpose built libraries acknowledge there’s an overhead to cross the native/WASM boundary. In my experience, measuring extensively, postMessage with native runtime objects outperforms any other ser/de solution that works with JS values.