Cachegrind under Xen

I have 开发者_JAVA百科an application written in C++ that someone else has written in a way that's supposed to maximally take advantage of cpu caches. This application runs on a guest Ubuntu OS that is using paravirtualization. I ran cachegrind and received very low cache miss rates.

Since my OS is virtualized, can I be sure that these values are in fact correct in showing that the cpu cache is being well used for my application?

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Cachegrind is a simulator. A real CPU may actually perform differently (e.g. your real CPU may have a different cache hierarchy to cachegrind, different sizes of cache, a different replacement policy and so forth). You would need to watch the real CPUs performance counters to know for sure how well your program was really performing on real hardware with respect to cache.