“Here’s all the ways we tell people not to use parallelism.”

I’m sorry, that’s not fair. It’s only a fraction of the ways we tell people not to use parallelism.

Multi-threading is difficult, which is why I said it’s a fucking obstacle. It’s the wrong model. The fact you’d try to “slap it on” is WHAT I AM TALKING ABOUT. You CANNOT just apply more cores to existing linear code. You MUST actively train people to write parallel-friendly code, even if it won’t necessarily run in parallel.

Javascript is a terrible language I work with regularly, and most of the things that should be parallel aren’t - and yet - it has abundant features that should be parallel. It has absorbed elements of functional programming that are excellent practice, even if for some goddamn reason they’re actually executed in-order.

Fetches are single-threaded, in Javascript. I don’t even know how they did that. Grabbing a webpage and then responding to an event using an inline function is somehow more rigidly linear than pre-emptive multitasking in Windows 95. But you should still write the damn things as though they’re going to happen in parallel. You have no control over the order they happen in. That and some caching get you halfway around most locks.

Javascript, loathesome relic, also has vector processing. The kind insisted upon by that pedant in the other subthread, who thinks the 512-bit vector units in a modern Intel chip don’t qualify, but the DSP on a Super Nintendo does. Array.forEach and Array.map really fucking ought to be parallelisable. Google could use its digital imperialism to force millions of devs to adopt better standards, just by following the spec and not processing keys in a rigid order. Bad code treating it like a simplified for-loop would break. Good code… wouldn’t.

We want people to write that kind of code.

Not necessarily code that will run in parallel. Just code that could.

Workload-centric thinking is the only thing that’s going to stop “let’s add a little parallelism, as a treat” from producing months of needless agony. Anything else has to be dissected, warped beyond recognition, and stitched back together, with each step taking more effort than starting over from scratch, and the end result still being slow and unreadable and fragile.