I was trying to use fio in a Python script to get some benchmarks, and I compared fio measurements with psutil.disk_io_counters(). On Windows 10, there is a very large discrepancy, but on macOS it’s much closer. After some investigation, I think the problem is the measured runtime. Does anybody know why Windows thinks a command takes longer than fio says it did?
For example on Windows Powershell:
(Measure-Command {fio --name larry --rw write --size 1G --directory D\:\temp | Write-Host}).TotalMilliseconds
Here, fio output shows run=4849-4849msec, while Measure-Command shows 6779ms (40% extra).
On macOS a similar command:
time fio --name larry --rw write --size 4G --directory /var/tmp/
Here, fio output shows run=6200-6200msec, while time shows 6583ms (real). Only 6% extra.
