Hi Babu, On 3/12/2024 10:07 AM, Moger, Babu wrote: > On 3/12/24 10:13, Reinette Chatre wrote: >> On 3/11/2024 8:40 AM, Moger, Babu wrote: >>> On 2/27/24 17:50, Reinette Chatre wrote: >>>> On 2/27/2024 10:12 AM, Moger, Babu wrote: >>>>> On 2/26/24 15:20, Reinette Chatre wrote: >>>>>> On 2/26/2024 9:59 AM, Moger, Babu wrote: >>>>>>> On 2/23/24 16:21, Reinette Chatre wrote: >>>> >>>>>>>> Apart from the "default behavior" there are two options to consider ... >>>>>>>> (a) the "original" behavior(? I do not know what to call it) - this would be >>>>>>>> where user space wants(?) to have the current non-ABMC behavior on an ABMC >>>>>>>> system, where the previous "num_rmids" monitor groups can be created but >>>>>>>> the counters are reset unpredictably ... should this still be supported >>>>>>>> on ABMC systems though? >>>>>>> >>>>>>> I would say yes. For some reason user(hardware or software issues) is not >>>>>>> able to use ABMC mode, they have an option to go back to legacy mode. >>>>>> >>>>>> I see. Should this perhaps be protected behind the resctrl "debug" mount option? >>>>> >>>>> The debug option gives wrong impression. It is better to keep the option >>>>> open to enable the feature in normal mode. >>>> >>>> You mentioned that it would only be needed when there are hardware or >>>> software issues ... so debug does sound appropriate. Could you please give >>>> an example of how debug option gives wrong impression? Why would you want >>>> users to keep using "legacy" mode on an ABMC system? >>> >>> We may not be able to use "-o debug" option to enable "legacy_mbm". >>> With debug option it will always go to legcay mbm even if ABMC is supported. >>> >>> For example when ABMC is supported, I cannot mount the resctrl with debug >>> option to test ABMC. >>> >>> I need to have a way to mount resctrl with ABMC and debug option. I can >>> add "-o legacy_mbm" to enable lecacy_mbm. >> >> I do not think it is necessary to add a unique debug option for this. > > It makes the code simple. > >> What if instead the "-o debug" mount option exposes the "original/legacy" > > Can you please elaborate on this? > > Did you mean following command to enable legacy mode? > > $echo "original/legacy" /sys/fs/resctrl/info/L3_MON/mbm_assign_control > > It feels like a overkill and confusing. I used the "original/legacy" text to make it clear which behavior I was referring to. It was not a proposal for a label used by user space to select the behavior. Isn't /sys/fs/resctrl/info/L3_MON/mbm_assign_control the file that will assign the counters to domains? That should not be the file used to select the behavior. You had /sys/fs/resctrl/info/L3_MON/mbm_assign with which user space selects behavior, no? Reinette
