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by rdtsc 148 days ago
You could first measure the perf impact of the fence instruction and then subtract that out? But yeah I guess it may not matter much for quick and dirty calibration loop.

I found somewhere (https://aloiskraus.wordpress.com/2018/06/16/why-skylakex-cpu...) that the pause instruction had this wild cycle difference between different CPU and it caused some grief, I had no idea. I stopped doing low level coding a while back.