Re: [OMPI users] Not getting zero-copy with custom datatype

2024-04-23 Thread George Bosilca via users
zero copy does not work with non-contiguous datatypes (it would require both processes to know the memory layout used by the peer). As long as the memory layout described by the type can be seen as contiguous (even if described otherwise), it should work just fine. George. On Tue, Apr 23, 2024

[OMPI users] Not getting zero-copy with custom datatype

2024-04-23 Thread Pascal Boeschoten via users
Hello, I'm using a custom datatype created through MPI_Type_create_struct() to send data with a dynamic structure to another process on the same node over shared memory, and noticed it's much slower than expected. I ran a profile, and it looks like it's not using CMA zero-copy, falling back to