> > > it will nonetheless require a lot of convincing that at best they get > moderate speed-ups, not the 580+x claimed in some of those early GPU > papers... > > Karli, we are talking about two different things. You are talking about performance, and I applaud you for that, but I am talking about giving customers what they want. They want to investigate GPUs. I will say that I do not anticipate seeing any performance improvement.
> > The fusion folks that I work with, and I assume other DOE offices, are >> just looking at their codes, subroutine by subroutine, and having postdocs >> look at GPUising them. We just need intelligent answers to their questions. >> Even if we as sentient and passionate human being have opinions on the >> approach that is implied by their questions, it is part of my job to just >> give them a professional answer. >> > > In the past ~18 months I've worked with applications that wanted to use > GPUs in just that manner. Needless to say that you end up with touching > almost everything to actually beat an existing (efficient) CPU-based > application by less than a factor of 2. This involves MPI-parallel > applications; it's much easier to get higher speedups if you don't need to > communicate across ranks. > > > I have enough now (thanks Jed and Lorena, et al!) to answer the AMGx >> question sufficiently, and if you could give me a quick assessment of where >> we are with hypre's GPU solver that would be great. >> > > does "work in progress" suffice? ;-) > I will advertise it "as is" (this is a term of art in US law). Thanks again, > > Best regards, > Karli > > > > > > >> On Thu, Jul 13, 2017 at 11:16 PM, Karl Rupp <[email protected] >> <mailto:[email protected]>> wrote: >> >> Hi Mark, >> >> I hear Hypre has support for GPUs in a May release. Any word on >> the status of using it in PETSc? >> >> >> as far as I know, it is currently not supported in PETSc. I'll have >> a look at it and see what needs to be done to enable it. >> >> >> And we discussed interfacing to AMGx, which is complicated >> (precluded?) by not releasing source. Anything on the potential >> of interfacing to AMGx? I think it would be great to make this >> available. It is on a lot of checkboxes. I would love to be able >> to say, yea you can use it. >> >> >> Lorena Barba's group actually interfaced PETSc to AMGx at some point >> (presented at GTC 2016 if I'm not mistaken). I'll reach out to them, >> maybe they have something to contribute. >> >> Best regards, >> Karli >> >> >>
