Posts tagged System-Tuning
Understanding RCCL Bandwidth and xGMI Performance on AMD Instinct™ MI300X
- 02 March 2025
Efficient inter-GPU communication is the backbone of high-performance AI and HPC workloads, where technologies like RCCL and xGMI play pivotal roles. However, some limitations in achieving theoretical peak bandwidth have raised questions about performance bottlenecks. In this blog we explain the limitations to achieve the theoretical maximum bandwidth in multi-GPU clusters, and teach you how to perform a set of diagnostics and performance-tuning strategies that will help you optimize RCCL and xGMI bandwidth on AMD MI300X systems. We will first introduce you to xGMI and its performance constraints, to RCCL and its bandwidth limitations, and then cover several practical benchmarks and best practices for maximizing RCCL efficiency.
Getting to Know Your GPU: A Deep Dive into AMD SMI
- 17 September 2024
For system administrators and power users working with AMD hardware, performance optimization and efficient monitoring of resources is paramount. The AMD System Management Interface command-line tool, amd-smi, addresses these needs.
Affinity part 2 - System topology and controlling affinity
- 16 April 2024
In Part 1 of the Affinity blog series, we looked at the importance of setting affinity for High Performance Computing (HPC) workloads. In this blog post, our goals are the following:
Affinity part 1 - Affinity, placement, and order
- 16 April 2024
Modern hardware architectures are increasingly complex with multiple sockets, many cores in each Central Processing Unit (CPU), Graphical Processing Units (GPUs), memory controllers, Network Interface Cards (NICs), etc. Peripherals such as GPUs or memory controllers will often be local to a CPU socket. Such designs present interesting challenges in optimizing memory access times, data transfer times, etc. Depending on how the system is built, hardware components are connected, and the workload being run, it may be advantageous to use the resources of the system in a specific way. In this article, we will discuss the role of affinity, placement, and order in improving performance for High Performance Computing (HPC) workloads. A short case study is also presented to familiarize you with performance considerations on a node in the Frontier supercomputer. In a follow-up article, we also aim to equip you with the tools you need to understand your system’s hardware topology and set up affinity for your application accordingly.