It is a single object that holds a pointer to every stream implementation and toggleable type so it can be universally passed around. Currently has a cudaStream and a hipStream but this is easily extendable to any other stream implementation. Best regards, Jacob Faibussowitsch (Jacob Fai - booss - oh - vitch) Cell: +1 (312) 694-3391

On Jan 9, 2021, at 18:19, Mark Adams <[email protected]> wrote:

 Is this stream object going to have Cuda, Kokkos, etc., implementations?

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On Sat, Jan 9, 2021 at 4:09 PM Jacob Faibussowitsch <[email protected]> wrote: I’m currently working on an implementation of a general PetscStream object. Currently it only supports Vector ops and has a proof of concept KSPCG, but should be extensible to other objects when finished. Junchao is also indirectly working on pipeline support in his NVSHMEM MR. Take a look at either MR, it would be very useful to get your input, as tailoring either of these approaches for pipelined algorithms is key.

Best regards,

Jacob Faibussowitsch (Jacob Fai - booss - oh - vitch) Cell: (312) 694-3391

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On Jan 9, 2021, at 15:01, Mark Adams <[email protected]> wrote:

I would like to put a non-overlapping ASM solve on the GPU. It's not clear that we have a model for this.

PCApply_ASM currently pipelines the scater with the subdomain solves. I think we would want to change this and do a 1) scatter begin loop, 2) scatter end and non-blocking solve loop, 3) solve-wait and scatter begging loop and 4) scatter end loop.

I'm not sure how to go about doing this. * Should we make a new PCApply_ASM_PARALLEL or dump this pipelining algorithm and rewrite PCApply_ASM? * Add a solver-wait method to KSP?

Thoughts?

Mark