Is :ConnectParallel() more performant?

[alexinite (alex)]

@EthicalRobot

The Basics of Parallelism

In order for your script to run in parallel with another script two things must be true:

• The scripts must be parented under different Actor instances
• The thread within a script must be desynchronized either via task.desynchronize() or Signal::ConnectParallel

@EthicalRobot

RBXScriptSignal:ConnectParallel

Instead of using task.desynchronize in signals, you can alternatively use a new ConnectParallel method. This method will run your code in parallel when that signal is triggered, which is more efficient than using Connect + task.desynchronize .

A common pattern for parallel execution that we expect to see is:

RunService.Heartbeat:ConnectParallel(function ()
    ... -- some parallel code that computes a state update
    task.synchronize()
    ... -- some serial code that changes the state of instances
end)

For the time being you will need to put all of the code that changes Instance properties in the serial portion of the update, while future releases will allow you to move more code from the serial to the parallel portion.

Parallel Lua Beta

It allows execution of multiple tasks in parallel, thus performing them at the same time. There are multiple issues with this. First of all, different threads will finish at different times depending on the workload. This can cause inconsistencies and you’ll have to yield the rest of the code until the working threads finish to avoid missing information. Next up, multiple threads can access and write the same information. Most other languages introduce mutex, while Luau has task.synchronize. W…

Gathered from Parallel Lua Beta - Updates / Announcements

From my knowledge, making it run in parallel will sync related (or exact) signals together.
Let’s say you were listening to Heartbeat in multiple scripts for example, instead of running them individually it will realize that there’s multiple and run Heartbeat once and execute everything using Heartbeat at once, instead of happening multiple times.

Now if I get this right, the Actor has to be different but the Signal which is being read has to be the same. If you’re reading the ChildAdded of Part1 and Part2 and parallel them, it will not execute at the same time (for obvious, performant reasons). However, if you were listening to ChildAdded in two different scripts it’s good practice to use ConnectParallel to lower RBXScriptSignal events firing too much.

In practicality, if it’s a signal for an event that is only connected once, just use Signal::Connect.