I am seeing funny results

I am seeing funny results

Steven Thomsen (Intel)'s picture

When attempting to run a network benchmark from within a VM, I am seeing throughput of approximately 14 GBytes/sec which go through a physical NIC rated at 1 GBit/sec. This seems to be a funny result. Also, my system clock is constantly incorrect and falling behind real time.

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Steven Thomsen (Intel)'s picture

This is because of "time drift". Essentially, the VMM sends clock ticks to the VM. If the VM does not respond quick enough, the tick is lost, which means the system time falls behind. Everything else keeps runniing, so all of your performance numbers are invalid. Using NTP can greatly help with this problem.

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