Hi, On Wed, Jan 22, 2025 at 02:20:25PM -0600, Babu Moger wrote: > Assign/unassign counters on resctrl group creation/deletion. Two counters > are required per group, one for MBM total event and one for MBM local > event. > > There are a limited number of counters available for assignment. If these > counters are exhausted, the kernel will display the error message: "Out of > MBM assignable counters". However, it is not necessary to fail the > creation of a group due to assignment failures. Users have the flexibility > to modify the assignments at a later time. If we are doing this, should turning mbm_cntr_assign mode on also trigger auto-assingment for all extant monitoring groups? Either way though, this auto-assignment feels like a potential nuisance for userspace. If the userspace use-case requires too many monitoring groups for the available counters, then the kernel will auto-assign counters to a random subset of groups which may or may not be the ones that userspace wanted to monitor; then userspace must manually look for the assigned counters and unassign some of them before they can be assigned where userspace actually wanted them. This is not impossible for userspace to cope with, but it feels awkward. Is there a way to inhibit auto-assignment? Or could automatic assignments be considered somehow "weak", so that new explicit assignments can steal automatically assigned counters without the need to unassign them explicitly? [...] Cheers ---Dave
