The number displayed is defined as the maximum difference of each thread over multiple runs, :
Imbalance is an indicator of the health of the result. Specifically, runs with a Imbalance number of should always be repeated.
High imbalance numbers can also be indicators for imbalanced workloads, where one core is doing significantly more work than another.
The imbalance number can be improved by reducing the difference in workload between different cores. If the current workload is very small, increasing the workload might also help.