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 calibra

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-cpus-are-sometimes-50-slower-how-intel-has-broken-existing-code/ 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.