The cloneTokenOnlyMap call in StorageProxy.getBatchlogEndpoints causes enormous amounts of CPU to be consumed on clusters with many vnodes. I created a patch to cache this data as a workaround and deployed it to a production cluster with 15,000 tokens. CPU consumption drop to 1/5th. This highlights the overall issues with cloneOnlyTokenMap() calls on vnodes clusters. I'm including the maybe-not-the-best-quality workaround patch to use as a reference, but cloneOnlyTokenMap is a systemic issue and every place it's called should probably be investigated.