Feature Request: Select thread/threadpool subset for @spawn

[IanButterworth]

Say you have a gui interface with multiple long-running, yielding background loops, and for example here JULIA_NUM_THREADS=3, and you wanted to maintain a responsive gui.

@spawn gui()
@spawn looper1()
@spawn looper2()
@spawn looper3()

In this example, it would be nice to be able to allow a dedicated thread for gui().

Something like this perhaps:

@spawn 1 gui()
@spawn 2 looper1()
@spawn 3 looper2()
@spawn 3 looper3()

or

@spawn 1 gui()
@spawn 2:nthreads() looper1()
@spawn 2:nthreads() looper2()
@spawn 2:nthreads() looper3()

An alternative would be to tell spawn not to use a specific thread, but I'm not sure what a good API would be for that

[JeffBezanson]

Looks like the same issue as #34267

[tro3]

@JeffBezanson is correct. Same issue. I was not planning on adding to ThreadPools (because the case is not structured-concurrent), but @vtjnash’s pin suggestion will do the trick for this. I’ll add just to cover the case, even though no real Pool is involved.

[JeffBezanson]

Closing as duplicate