Virtual Machines

Chapter Four Dynamic Binary Optimization

After compatibility, performance is often the most important consideration in virtual machine implementations. This chapter picks up where the previous chapter left off and focuses on improving performance of the emulation process. When compared with interpretation, merely performing simple binary translation yields a large (order of magnitude) performance gain. However, applying optimizations on translated code provides additional improvements over basic translation.

In many VMs, simple optimizations are performed just to smooth some of the “rough edges” left over from an initial binary translation. For example, a simple instruction-at-a-time translation of the first two IA-32 instructions in Figure ...