Exploiting dead value information
Exploiting dead value information
复制标题
利用死值信息
DOI：
10.1109/micro.1997.645804
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
C. Fischer
中科院分区：
文献类型：
--
作者：
Milo M. K. Martin;A. Roth;C. Fischer
我们描述了死值信息(DVI)，并介绍了利用它的三个新的优化。DVI断言某些寄存器值是死的，这意味着它们在被覆盖之前不会被读取。处理器可以使用DVI来跟踪失效寄存器，并在过程调用和上下文切换时动态地从执行流中消除不必要的保存和恢复指令。结果表明，对于过程调用，动态保存和恢复实例可以减少46%；对于上下文切换，动态保存和恢复实例可以减少51%。此外，过程调用的保存/还原消除可以将整体性能提高高达5%。DVI还允许处理器高效地管理物理寄存器，从而降低物理寄存器堆的大小要求。当系统时钟频率与寄存器堆周期时间成正比时，这种优化可以提高性能。只需几条新指令和最少的额外硬件结构即可支持所有这些优化。
We describe dead value information (DVI) and introduce three new optimizations which exploit it. DVI provides assertions that certain register values are dead, meaning they will not be read before being overwritten. The processor can use DVI to track dead registers and dynamically eliminate unnecessary save and restore instructions from the execution stream at procedure calls and context switches. Our results indicate that dynamic saves and restore instances can be reduced by 46% for procedure calls and by 51% for context switches. In addition, save/restore elimination for procedure calls can improve overall performance by up to 5%. DVI also allows the processor to manage physical registers efficiently, reducing the size requirements of the physical register file. When the system clock rate as proportional to the register file cycle time, this optimization can improve performance. All of these optimizations can be supported with only a few new instructions and minimal additional hardware structures.