Comment by grishka
4 hours ago
Running code by itself isn't that bad, it's the fact that browser developers have decided for some reason that this code needs to be as performant as possible, so, JIT.
I don't get it! The way JS is typically used, it doesn't even benefit from JIT all that much. Making ajax requests, doing stuff with strings, and moving DOM elements around doesn't need every CPU clock cycle to be used as optimally as possible. It's exceedingly rare for websites to actually be doing something that needs raw performance. And SPAs will be slow no matter what.
I disagree about JIT performance not mattering. I enabled "Lockdown Mode" on iOS which disables the JIT for the mentioned security reasons, and it causes a very noticeable lagginess on many sites. Of course, the primary cause is the unnecessary JS monstrosities wasting CPU cycles. But practically speaking I can say that disabling the JIT results in a very subpar experience of many JS heavy pages.
That's largely because a lot of developers have made the devil's bargain of replacing standard web stuff with badly re-implemented JS versions of same. People did it because they could, but never considered if they should.
See most of the ecosystem around React, for reference. It's idiotic that things like URL management are done in Javascript. Or form controls. I guarantee that if we stopped doing this kind of stuff, JIT wouldn't matter.
To some extent this is just saying "developers will depend upon the performance given to them", and that's true, but it's also true that as soon as things like V8 and Node appeared, JS became ubiquitous. Pandora's container, if you will.
It will also increase power consumption because your CPU has to do more work to run the same code.
you are talking about the effect, not the cause.
Sites are slow because with all that excess performance they do more tracking, instead of keeping the website as-is.
Because that's the only thing business managers can come up with in that situation. It's a misaligned goal of users vs businesses.
In my opinion the "user agent" behavior of browsers is long gone, because they're not acting on behalf of their users anymore. They're acting on behalf of businesses.
Agree. Chrome should just disable JIT by default and boom many website owner will start to optimize their website.
jira and confluence come to mind...
I suspect the people who agree to buy Jira & Confluence are not particularly heavy users of them. At least, that's the only explanation I can fathom for their continued sales.
Is it their app’s features that are slow, or the analytics bolted on top?
1 reply →
> SPAs will be slow no matter what.
Uh…no?
You’re presumably talking about specific terrible prebuilt frameworks - not someone building a nice vanilla SPA.
At this point SPA pretty much implies React. But even if you optimize everything the best you could and avoid any third-party runtime dependencies, it's still going to be significantly more work to make API requests and do client-side rendering vs just rendering HTML server-side.