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Daniel Lemire·05 November 2026·1 min read

A performance trap: when store forwarding fails

A store does not go straight into the cache. Waiting for that write would stall the processor.

tech

A store does not go straight into the cache. Waiting for that write would stall the processor. It sits in a store buffer, and a later load can take its bytes from that buffer. That is store forwarding. Forwarding works when the load is the same size as the store, or smaller and completely inside Continue reading A performance trap: when store forwarding fails

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