Re: [starpu-devel] Creating tasks that are dependent on resources

[Samuel Thibault <samuel.thibault@inria.fr>]

Hello,

Doru Adrian Thom Popovici, le mar. 28 nov. 2023 10:07:46 -0800, a ecrit:
> I am trying to understand if it is possible to launch tasks that require
> different amounts of threads.
> 
> For example, I have three tasks:
> 
> A requires 4 threads
> B requires 2 thread
> C requires 6 threads
> 
> I have a budget of 8 threads, so A and B can go first, however C needs to 
> wait
> because it needs 6 threads but only two are available.
> 
> I could also run C and B first, and then A has two waits.
> 
> I have been reading the StarPU manual, however I am not clear if this 
> feature
> is available.

With combined workers it is possible with the pheft scheduler. To
specify the amount of threads that a task should use, you can use the
can_execute callback and its workerid parameter and the
starpu_combined_worker_get_description function to get the size and
return 1 only if it's the one you want.

Note however that pheft is a released-first scheduler, without
backfilling (mostly a proof of concept). Help welcome on implementing
better parallel-task schedulers :)

Samuel