mlua_scheduler

A Roblox-like scheduler for mlua

Features

• Correctness and performance are king. mlua_scheduler is orders of magnitude faster than Lune 0.8's scheduler as of time of writing.
• Simple with simple primitives for getting results out.
• Properly working coroutine.yield and coroutine.resume functions that produce equivalent (mostly) results in Roblox's own Luau + Task Scheduling code
• Both mlua non-send and send features supported (thanks to rust async wizardry).
• Custom async function handling that works with Lua's coroutine design paradigm without breaking on edge-cases.
• Simple callback API for controlling the scheduler (SchedulerFeedback trait)

Deviations from Roblox's scheduler

• Thread arguments are not preloaded to the stack due to mlua limitations. This is normally not a problem but may cause side-effects. For example, see tests/jacktest2.luau.

local task = task or require("@lune/task")
local thread = task.delay(1, function(foo)
    print(foo)
    print(coroutine.yield())
    print("c")
    print(coroutine.yield())
    print("e")
end, "b")

task.spawn(thread, "a")

task.delay(2, function()
    coroutine.resume(thread, "d")
end)

Inner Workings

• Waiting tasks are stored in a priority queue (binary heap) hence allowing the scheduler to only process ready tasks.
• Deferred tasks and async tasks are stored in a standard VecDeque.
• When processing, the scheduler runs in the following order: async -> waiting -> deferred.
• For proper async support, you should use the schedulers provided async module (see below). Thanks to recent scheduler reworks, the schedulers async system is as fast or faster than mlua's create_async_function. The best way to avoid using these types of functions is to entirely disable mlua async altogether in your features for mlua [omit async from features = ['mlua']].

Fast Mode

At the expense of fully breaking mlua's async support (create_async_function and co.)