FunBike31thank you for your explanation and 1 more thing
Indeed, the doc is almost non-existent for groups, it seems that this is related to CPU clusters and task numbers.
With upmigrate, a task using for example 80% of a 1.8 CPU for a given time will switch to CPU 2.42, if it still uses 80% it will switch to 2.84 or go down to 1.8 if it uses -60%.
For Groups, it would be the same but only if 2, 3 or 4 tasks would be eligible, example if 3 tasks use 80% of the 1.8 cores they would pass on the 2.42 cores
The values given are only examples and other parameters such as temperature and time are taken into account
2.84GHz Single-Core Kryo 680
2.42GHz Triple-Core Kryo 680
1.8GHz Quad-Core Kryo 680
It is risky to risk this setting without a perfect knowledge of the kernel, the game software concerned and the analysis and monitoring tools, not to mention that the possible gain (on a kernel with good default values) is negligible. compared to simpler operations such as the deletion of numerous logs, which in addition do not generate an increasing temperature, which is already difficult to control.
Good luck in your research