Posts by Noel Chalmers
GPU-aware MPI with ROCm
- 08 June 2023
MPI is the de facto standard for inter-process communication in High-Performance Computing. MPI processes compute on their local data while extensively communicating with each other. This enables MPI programs to be executed on systems with a distributed memory space e.g. clusters. There are different types of communications supported in MPI including point-to-point and collective communications. Point-to-point communication is the basic communication mechanism in which both the sending process and the receiving process take part in the communication. The sender has a buffer that holds the message and an envelope containing information that will be used by the receiver side (e.g., message tag, the sender rank number, etc.). The receiver uses the information in the envelope to select the specified message and stores it in its receiver buffer. In collective communication, messages can be exchanged among a group of processes rather than just two of them. Collective communication provides opportunities for processes to perform one-to-many and many-to-many communications in a convenient, portable and optimized way. Some examples of collective communications include broadcast, allgather, alltoall, and allreduce.
AMD matrix cores
- 14 November 2022
Matrix multiplication is a fundamental aspect of linear algebra and it is an ubiquitous computation within High Performance Computing (HPC) Applications. Since the introduction of AMD’s CDNA Architecture, Generalized Matrix Multiplication (GEMM) computations are now hardware-accelerated through Matrix Core Processing Units. Matrix Core accelerated GEMM kernels lie at the heart of BLAS libraries like rocBLAS but they can also be programmed directly by developers. Applications that are throughput bound by GEMM computation can achieve additional speedups by utilizing Matrix Cores.