There are many ways to measure performance. Some common metrics include: Metrics that are more abstract have the advantage that they are typically simple to reason about and applicable across a variety of implementations. For example, host instructions may be counted relatively easily for each of a variety of target instructions, and the counts are relatively isolated from the structure of the caches and microarchitecture. Conversly, concrete metrics tend to more accurately reflect all related costs. For example the effects of caches and microarchitectures are included.l

It is worth noting that few reports give enough information about the measurement methodology in order to make a valid comparison. For example, if dilation is ``typically'' 20x, what is ``typical'', and what is the performance for ``non-typical'' workloads?

From instruction-set simulation and tracing