Hi Reinette, On 3/12/24 12:15, Reinette Chatre wrote: > 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 ok. > select the behavior. You had /sys/fs/resctrl/info/L3_MON/mbm_assign > with which user space selects behavior, no? Yes. I think we can use this file(/sys/fs/resctrl/info/L3_MON/mbm_assign). Thanks Babu Moger
