What Is RDMA?_
Remote Direct Memory Access (RDMA) enables one computer to access another computer's memory directly over the network without involving either computer's CPU or operating system. RDMA is essential for GPU cluster performance because it minimizes latency for the frequent, small data transfers that distributed AI training requires.
Technical Details
RDMA bypasses the traditional network stack (application → kernel → TCP/IP → NIC) by allowing applications to read and write directly to remote memory through the network adapter. This reduces latency from microseconds to sub-microsecond levels and eliminates CPU overhead for data movement. In GPU clusters, GPUDirect RDMA extends this to allow network adapters to access GPU memory directly, enabling GPU-to-GPU transfers across the network without staging through CPU memory. RDMA is supported natively on InfiniBand and on Ethernet via RoCE (RDMA over Converged Ethernet) v2. Network cable quality matters for RDMA because any physical-layer errors cause retransmissions that negate the latency benefits.
How Leviathan Systems Works with RDMA
Leviathan Systems ensures the physical network infrastructure supports RDMA performance by maintaining strict cable quality standards, proper connector termination, and comprehensive testing that validates error-free operation.