Orinoco: Ordered Issue and Unordered Commit with Non-Collapsible Queues

Modern out-of-order processors call for more aggressive scheduling techniques such as priority scheduling and out-of-order commit to make use of increasing core resources. Since these approaches prioritize the issue or commit of certain instructions, they face the conundrum of providing the capacity efficiency of scheduling structures while preserving the ideal ordering of instructions. Traditional collapsible queues are too expensive for today's processors, while state-of-the-art queue designs compromise with the pseudo-ordering of instructions, leading to performance degradation as well as other limitations.