Hi Ilpo, On 9/11/2023 4:19 AM, Ilpo Järvinen wrote: > 5% difference upper bound for success is a bit on the low side for the "a bit on the low side" is very vague. > MBA and MBM tests. Some platforms produce outliers that are slightly > above that, typically 6-7%. > > Relaxing the MBA/MBM success bound to 8% removes most of the failures > due those frequent outliers. This description needs more context on what issue is being solved here. What does the % difference represent? How was new percentage determined? Did you investigate why there are differences between platforms? From what I understand these tests measure memory bandwidth using perf and resctrl and then compare the difference. Are there interesting things about the platforms on which the difference is higher than 5%? Could those be systems with multiple sockets (and thus multiple PMUs that need to be setup, reset, and read)? Can the reading of the counters be improved instead of relaxing the success criteria? A quick comparison between get_mem_bw_imc() and get_mem_bw_resctrl() makes me think that a difference is not surprising ... note how the PMU counters are started and reset (potentially on multiple sockets) at every iteration while the resctrl counters keep rolling and new values are just subtracted from previous. Reinette
