Google Releases TPU Sync: Open-Source KV Cache Transfer for TPUs

Google Cloud has released TPU Sync, an Apache-2.0 C++ library with Python wheels for PyTorch and JAX that moves KV caches and model weights across TPU HBM, pinned host DRAM, shared storage and the data center network using layout-preserving asynchronous DMA. Google reports over 90% lower KV transfer latency on 235B to 480B parameter MoE models, with Qwen3 235B median KV transfer latency dropping from several seconds to about 230 ms in internal tests on TPU v7x. The README says it is not yet recommended for general use, and the RL weight-broadcast and storage tiering features are experimental.