Coarse-grained instruction commit mechanisms enabled the effective size of the instruction window to be as large as possible by committing a group of instructions atomically. Within a group, the reorder buffer (ROB) and physical register file (PRF) entries are conservatively managed, and thus the instruction window can handle more in-flight instructions beyond the hardware limit. However, previous approaches have suffered from high storage requirements for managing group information and unbalanced lifetime of instruction window resources, i.e., the ROB and PRF. In this paper, we propose an OverCome microarchitecture based on a history-based approach to address these problems. First, OverCome retains the conservative allocation of the ROB regardless of the group size limit, thereby providing high scalability. Second, it handles the information of numerous groups with a low storage cost. These two techniques achieve a significant reduction in the pressure on the ROB; thus, a new bottleneck arises: the pressure on the PRF. To address this issue, we propose a novel register renaming technique to reduce the lifetime of physical registers to a large extent, by tightly coupling the early release and lazy allocation schemes. Thus, the proposed design strikes a balance between the ROB and PRF requirements. Detailed evaluation of the proposed techniques on a state-of-the-art superscalar processor shows that our proposals augment the effective size of the instruction window by more than $4\times$4×, with a net overhead of less than 3 percent of the core area.

中文翻译：

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克服：带有切换寄存器重命名的粗粒度指令提交

粗粒度指令提交机制通过原子地提交一组指令使指令窗口的有效大小尽可能大。在一个组内，重新排序缓冲区 (ROB) 和物理寄存器文件 (PRF) 条目受到保守管理，因此指令窗口可以处理更多超出硬件限制的运行中指令。然而，以前的方法存在管理组信息的高存储要求和指令窗口资源（即 ROB 和 PRF）的不平衡生命周期。在本文中，我们提出了一种基于基于历史的方法的 OverCome 微体系结构来解决这些问题。首先，OverCome 保留了 ROB 的保守分配而不受组大小限制，从而提供了高可扩展性。第二，它以较低的存储成本处理众多群组的信息。这两种技术实现了对 ROB 压力的显着降低；因此，出现了一个新的瓶颈：PRF 的压力。为了解决这个问题，我们提出了一种新颖的寄存器重命名技术，通过将早期发布和延迟分配方案紧密耦合，在很大程度上减少物理寄存器的生命周期。因此，提议的设计在 ROB 和 PRF 要求之间取得了平衡。在最先进的超标量处理器上对所提议技术的详细评估表明，我们的提议将指令窗口的有效大小增加了超过 为了解决这个问题，我们提出了一种新颖的寄存器重命名技术，通过将早期发布和延迟分配方案紧密耦合，在很大程度上减少物理寄存器的生命周期。因此，提议的设计在 ROB 和 PRF 要求之间取得了平衡。在最先进的超标量处理器上对所提议技术的详细评估表明，我们的提议将指令窗口的有效大小增加了超过 为了解决这个问题，我们提出了一种新颖的寄存器重命名技术，通过将早期发布和延迟分配方案紧密耦合，在很大程度上减少物理寄存器的生命周期。因此，提议的设计在 ROB 和 PRF 要求之间取得了平衡。在最先进的超标量处理器上对所提议技术的详细评估表明，我们的提议将指令窗口的有效大小增加了超过$4\times$4×，净开销不到核心区域的 3%。