Latency-based instruction reservation station clustering in a scheduler circuit in a processor

Abstract

Latency-based instruction reservation clustering in a scheduler circuit in a processor is disclosed. The scheduler circuit includes a plurality of latency-based reservation circuits each having an assigned producer instruction cycle latency. Producer instructions with the same cycle latency can be clustered in the same latency-based reservation circuit. Thus, the number of reservation entries is distributed among the plurality of latency-based reservation circuits to avoid or reduce an increase in the number of scheduling path connections and complexity in each reservation circuit to avoid or reduce an increase in scheduling latency. The scheduling path connections are reduced for a given number of reservation entries over a non-clustered pick circuit, because signals (e.g., wake-up signals, pick-up signals) used for scheduling instructions in each latency-based reservation circuit do not have to have the same clock cycle latency so as to not impact performance.