Despite very accurate branch predictors, branch misses remain an important source of performance limiters, especially for irregular applications. To ensure in-order commit, branch miss recovery is done in-order: all instructions after the oldest branch miss are flushed, even if they eventually reconverge with the correct path. We propose a technique to limit flushing to real wrong-path instructions only, allowing the resolution of newer branch misses while an older one is not yet resolved. Our technique involves minimal additions to a conventional out-of-order processor, by reusing existing checkpoint mechanisms and relying on programmer/compiler inserted hints to detect data and control independence. We evaluate the technique on graph benchmarks, resulting in up to 2× increase in performance.

中文翻译：

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中断有序分支未命中恢复

尽管分支预测器非常准确，但分支未命中仍然是性能限制器的重要来源，尤其是对于不规则的应用程序。为了确保按顺序提交，分支未命中恢复是按顺序完成的：最旧的分支未命中之后的所有指令都会被刷新，即使它们最终会重新收敛到正确的路径。我们提出了一种技术来限制刷新到真正的错误路径指令，允许解决较新的分支未命中而旧的尚未解决。我们的技术通过重用现有的检查点机制并依靠程序员/编译器插入的提示来检测数据和控制独立性，从而对传统的乱序处理器进行最少的添加。我们在图基准测试中评估了该技术，从而使性能提高了 2 倍。