Making CUDA Checkpointing 15x Faster on a B300: A Worklog

Henry Zhu and Vimarsh Sathia profiled NVIDIA's cuda-checkpoint on a B300 node checkpointing GLM-5.3 on vLLM across two GPUs. Baseline throughput was about 6 GB/s checkpoint and 3 GB/s restore, far below PCIe's 64 GB/s. Causes were a single CPU copy thread, page-faulting allocation, per-call CLI startup, and cross-socket NUMA reads. Pinning memory to the local node, huge pages, preallocation, and 8 workers with 16 staging slots cut a cycle from tens of seconds to 11.3 s. The headline 15x figure is unsourced and measured on one workload.