Hi Reinette, On 7/8/25 10:21, Reinette Chatre wrote: > Hi Babu, > > On 7/8/25 6:27 AM, Moger, Babu wrote: >> On 7/7/2025 5:35 PM, Moger, Babu wrote: >>> On 7/3/25 11:21, Reinette Chatre wrote: >>>> On 7/2/25 12:04 PM, Moger, Babu wrote: >>>>> On 7/2/25 12:21, Reinette Chatre wrote: >>>>>> On 7/2/25 9:42 AM, Moger, Babu wrote: >>>>>>> On 6/25/25 18:39, Reinette Chatre wrote: >>>>>>>> On 6/13/25 2:05 PM, Babu Moger wrote: >>> Changed the changelog. How does this look? >>> >>> "The default monitoring mode and with BMEC (Bandwidth Monitoring Event >>> Configuration) support, events are configured using the files >>> mbm_total_bytes_config or mbm_local_bytes_config in >>> /sys/fs/resctrl/info/L3_MON/. >>> >>> When the mbm_event counter assignment mode is enabled, event configuration >>> is handled via the event_filter files under >>> /sys/fs/resctrl/info/L3_MON/event_configs/. This mode allows users to read >>> and write memory transaction events using human-readable strings, making >>> the interface easier to use and more intuitive. Going forward, this >>> mechanism can support assigning multiple counters to RMID, event pairs and >>> may be extended to allow flexible, user-defined event names. >>> >>> Given these changes, hide the BMEC-related files when the mbm_event >>> counter assignment mode is enabled. Also, update the mon_features display >>> accordingly." >>> >> >> Here is another update. >> >> fs/resctrl: Hide the BMEC related files when mbm_event mode is enabled >> >> The default monitoring mode and with BMEC (Bandwidth Monitoring Event >> Configuration) support, events are configured using the files >> mbm_total_bytes_config or mbm_local_bytes_config in >> /sys/fs/resctrl/info/L3_MON/. >> >> When the mbm_event counter assignment mode is enabled, event configuration is handled via the event_filter files under >> /sys/fs/resctrl/info/L3_MON/event_configs/. This mode enables users to >> configure memory transaction events using human-readable strings, providing a more intuitive and user-friendly interface. In the future, this mechanism could be extended to support assigning multiple counters to RMID-event pairs, as well as customizable, user-defined event names. Also, the presence of BMEC-related configuration files may cause confusion when the mbm_event counter assignment mode is enabled. >> >> To address this, these files are now hidden when the mode is active. >> Additionally, the mon_features display has been updated to reflect this >> change. > > I do not find a concrete motivation in this changelog. The terms "may cause > confusion" and "providing a more intuitive and user-friendly interface." are > vague and not something that I think provides a good motivation for disabling > an entire interface. > > I aim to write a draft below that I hope will help make this changelog more > convincing. Please do improve it: > > > fs/resctrl: Disable BMEC event configuration when mbm_event mode is enabled > > The BMEC (Bandwidth Monitoring Event Configuration) feature enables per-domain > event configuration. With BMEC the MBM events are configured using > the mbm_total_bytes_config or mbm_local_bytes_config files in > /sys/fs/resctrl/info/L3_MON/ and the per-domain event configuration > affects all monitor resource groups. > > The mbm_event counter assignment mode enables counters to be assigned to > RMID (i.e a monitor resource group), event pairs, with potentially unique > event configurations associated with every counter. > > There may be systems that support both BMEC and mbm_event counter assignment > mode, but resctrl supporting both concurrently will present a conflicting > interface to the user with both per-domain and per RMID, event configurations > active at the same time. > > mbm_event counter assignment provides most flexibility to user space and > aligns with Arm's counter support. On systems that support both, disable BMEC > event configuration when mbm_event mode is enabled by hiding the > the mbm_total_bytes_config or mbm_local_bytes_config files when mbm_event mode > is enabled. Ensure mon_features always displays accurate information about > monitor features. > Looks good. -- Thanks Babu Moger
