基于region的动态重用技术

1.引言指令之间的依赖使超标量计算机的处理器每个时钟周期只能执行平均1.7到2.1条指令。同时指令的运行带有很大的重复性。指令重复是指一条静态指令多次动态执行得到的结果是一样的。通常的情况下,对一条计算指令,如果它的输入是相同的,那么其结果也是相同的。但是,也存在输入不同、但结果相同的情况;例如两个数做布尔运算,在很多种情况下,结果都是一样的。在本文中我们说一条指令被重复当且仅

Dynamic Reuse Based on Region

Empirical observations suggest that many instructions and groups of instructions having the same inputs, and producing the same outputs. Such instructions do not have to be executed repeatedly -their result can be obtained from records where they have been saved previously. This paper proposes an approach that uses compiler technique to exploit reuse for instruction group. In this approach, the compiler first identifies code regions whose computation can be reused during dynamic execution. For each region, a library routing is invoked before the instruction in the region is executed. The function of the library routes is to record several instances of the region execution,including input register values and output register values. When it is found that a region has an instance that can be reused,then all the instructions in the region can be skipped and hence improve the performance.