OP-DSL / OP2-Common

OP2: open-source framework for the execution of unstructured grid applications on clusters of GPUs or multi-core CPUs
https://op-dsl.github.io
Other
98 stars 46 forks source link

GPUDirect without SOA #239

Closed TobyFlynn closed 1 year ago

TobyFlynn commented 1 year ago

I'm coming across an issue when using OP2's -gpudirect flag without code generating for SOA on GPUs and I've been able to recreate the issue using the airfoil sample app (the exact one I was using is the HDF5 double precision airfoil). When running with SOA code generation, everything works fine and the test passes for airfoil but if SOA is not used the test on the residual fails. There are no segfaults or runtime errors, the app is just producing an incorrect solution as far as I can tell. I've had an initial look at the halo exchange code that supports gpudirect and I couldn't see the issue immediately but I will have a more thorough look this week.

reguly commented 1 year ago

Thanks for looking into this - I have also seen issues with -gpudirect on MG-CFD, even with SoA, but had no time yet to investigate..

On 2023. Apr 19., at 0:16, Toby Flynn @.***> wrote:

I'm coming across an issue when using OP2's -gpudirect flag without code generating for SOA on GPUs and I've been able to recreate the issue using the airfoil sample app (the exact one I was using is the HDF5 double precision airfoil). When running with SOA code generation, everything works fine and the test passes for airfoil but if SOA is not used the test on the residual fails. There are no segfaults or runtime errors, the app is just producing an incorrect solution as far as I can tell. I've had an initial look at the halo exchange code that supports gpudirect and I couldn't see the issue immediately but I will have a more thorough look this week.

— Reply to this email directly, view it on GitHub https://github.com/OP-DSL/OP2-Common/issues/239, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAJWVVKXTQBPTO74DYL4QITXB4HCRANCNFSM6AAAAAAXDHQ45U. You are receiving this because you are subscribed to this thread.