Hi Babu, On 5/8/2024 4:29 PM, Moger, Babu wrote: > On 5/8/24 15:41, Reinette Chatre wrote: >> On 5/8/2024 1:07 PM, Moger, Babu wrote: >>> On 5/7/24 15:26, Reinette Chatre wrote: >>>> On 5/6/2024 10:18 AM, Moger, Babu wrote: >>>>> On 5/3/24 18:24, Reinette Chatre wrote: >>>>>> On 3/28/2024 6:06 PM, Babu Moger wrote: >>>>>> >>>>>>> a. Check if ABMC support is available >>>>>>> #mount -t resctrl resctrl /sys/fs/resctrl/ >>>>>>> >>>>>>> #cat /sys/fs/resctrl/info/L3_MON/mbm_assign >>>>>>> [abmc] >>>>>>> legacy_mbm >>>>>>> >>>>>>> Linux kernel detected ABMC feature and it is enabled. >>>>>> >>>>>> Please note that this adds the "abmc" feature to the resctrl >>>>>> *filesystem* that supports more architectures than just AMD. Calling the >>>>>> resctrl filesystem feature "abmc" means that (a) AMD needs to be ok with >>>>>> other architectures calling their features that are >>>>>> similar-but-maybe-not-identical-to-AMD-ABMC "abmc", or (b) this needs >>>>>> a new generic name. >>>>> >>>>> It should not a problem if other architecture calling abmc for similar >>>>> feature. But generic name is always better if there is a suggestion. >>>> >>>> "should not a problem" does not instill confidence that AMD is >>>> actually ok with this. >>> >>> The feature "ABMC" has been used in the public document already to refer >>> this feature. >>> https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/programmer-references/24594.pdf >> >> It is clear to me that Assignable Bandwidth Monitoring Counters (ABMC) is the >> name of the AMD feature. The question is whether users can use the >> same name to interact with "similar but maybe not identical" features from other >> architectures, which is what this series enables. >> >>> If there comes a conflict then we can change it to amd_abmc. Didn't see >>> any conflict at this pint. >> >> How do you envision this? The resctrl filesystem interface is intended to be >> architecture neutral so it is not obvious to me how "amd_abmc" is expected >> to look? Why would it be necessary to have different architecture specific names >> for a similar feature from different architectures that users interact with in >> the same way? Sounds to me as though this just needs a new non-AMD marketing name. > > I think I misunderstood it. > It is not a concern to have a same name("abmc") for similar feature across > the architectures. Thank you for confirming. This joins BMEC and SMBA in this regard. > ABMC is also kind of generic. I am open to other generic suggestions. I > think we should have "assign" and "monitor" words in them. One thing we can consider is to move to a simple "enable"/"disable" interface for events. Users do not really need to know that hardware needs to "assign a counter" to an event for it to measure. Yes, user space can infer some of this by the number of events that can be "enabled" at a time, but the concept of "assign a hardware counter" is abstract and does not directly map to (as I understand) the soft-RMID approach for other AMD hardware. Peter reminded us a while back [1] that "assign" has a variety of meanings, even among AMD, so we should aim to avoid any confusion. Reinette [1] https://lore.kernel.org/lkml/CALPaoCjg-W3w8OKLHP_g6Evoo03fbgaOQZrGTLX6vdSLp70=SA@xxxxxxxxxxxxxx/
