Finer control over the DefaultTaskPoolOptions

[ElliotB256]

What problem does this solve or what need does it fill?

I would like finer control over the thread pool and I'm not sure how to modify the DefaultTaskPoolOptions to achieve this.
Following the examples, it seems I can use some methods to create a DefaultTaskPoolOptions, e.g.:

DefaultTaskPoolOptions::with_num_threads(4)

but this doesn't provide enough flexibility to e.g. disable the io pool or change the ratio of async_compute to compute threads.

I can create a DefaultTaskPoolOptions struct, but assigning values to some of the fields is not possible.
The task_pool_options mod in the core lib is not marked as pub, which prevents defining e.g. a TaskPoolThreadAssignmentPolicy.
Ideally, I would do something like:

    let mut pool = DefaultTaskPoolOptions::default();
    pool.io = bevy::core::task_pool_options::TaskPoolThreadAssignmentPolicy { min_threads: 0, max_threads: 2, percent: 0.2};

What solution would you like?

Define the task_pool_options mod as pub to allow construction of a DefaultTaskPoolOptions with all fields defined.

What alternative(s) have you considered?

Alternatively, there could be more methods for the DefaultTaskPoolOptions which modifies the compute, async_compute and io pools. Perhaps a DefaultTaskPoolBuilder could provide a way to configure a DefaultTaskPoolOptions?

[TanTanDev]

I agree!
I'm currently only utilizing an AsyncComputeTaskPool, and I would greatly benefit if I could increase the threads it's using.
Since my computer only allows for 4 threads, I only ever get to utilize 1 thread since AsyncComputeTaskPool is assigned 25% threads.

Opening up customization would greatly benefit my project I believe.

[bjorn3]

All fields are already public. DefaultTaskPoolOptions is also exported so you can do something like pool.io.min_threads = 0;. I do agree that TaskPoolThreadAssignmentPolicy should be exported too.

[TanTanDev]

II see, so this is what we currently have to do to modify the DefaultTaskPoolOptions

    let mut task_pool_settings = DefaultTaskPoolOptions::default();
    task_pool_settings.async_compute.percent = 1.0f32;
    task_pool_settings.compute.percent = 0.0f32; // i currently only use async_compute
    task_pool_settings.io.percent = 0.0f32; // always use 1
    .... app setup code
    .insert_resource(task_pool_settings)

I don't think that is the most 'elegant' way to write it, if the TaskPoolThreadAssignmentPolicy was pub in the namespace
We would then be able to write it this way:

        .insert_resource(DefaultTaskPoolOptions{
            async_compute: TaskPoolThreadAssignmentPolicy{
                min_threads: 1,
                max_threads: 4,
                percent: 0.25,
            },
            ..Default::default()
        })

I guess we can get around it by doing the first method, but I feel like the second way is more what I would expect.