Posts by Jayacharan Kolla
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.