Hi Reinette, On 9/19/22 11:42, Reinette Chatre wrote: > Hi Babu, > > On 9/19/2022 8:46 AM, Moger, Babu wrote: >> Hi Reinette, >> >> On 9/16/22 10:58, Reinette Chatre wrote: >>> Hi Babu, >>> >>> On 9/7/2022 11:01 AM, Babu Moger wrote: >>>> Add two new sysfs files to read/write the event configuration if >>>> the feature Bandwidth Monitoring Event Configuration (BMEC) is >>>> supported. The file mbm_local_config is for the configuration >>>> of the event mbm_local_bytes and the file mbm_total_config is >>>> for the configuration of mbm_total_bytes. >>>> >>>> $ls /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local* >>>> /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes >>>> /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_config >>>> >>>> $ls /sys/fs/resctrl/mon_data/mon_L3_00/mbm_total* >>>> /sys/fs/resctrl/mon_data/mon_L3_00/mbm_total_bytes >>>> /sys/fs/resctrl/mon_data/mon_L3_00/mbm_total_config >>>> >>> This patch makes the mbm*config files per monitor group. Looking >>> ahead at later patches how the configuration is set it is not clear >>> to me that this is the right place for these configuration files. >>> >>> Looking ahead to patch 10 there is neither rmid nor closid within >>> the (MSR_IA32_EVT_CFG_BASE + index) register - it only takes >>> the bits indicating what access types needs to be counted. Also >>> in patch 10 I understand that the scope of this register is per L3 cache >>> domain. >> Yes. Scope of MSR_IA32_EVT_CFG_BASE per L3 domain. >>> Considering this, why is the sysfs file associated with each >>> monitor group? >> Please see the response below. >>> For example, consider the following scenario: >>> # cd /sys/fs/resctrl >>> # mkdir g2 >>> # mkdir mon_groups/m1 >>> # mkdir mon_groups/m2 >>> # find . | grep mbm_local_config >>> ./mon_data/mon_L3_00/mbm_local_config >>> ./mon_data/mon_L3_01/mbm_local_config >>> ./g2/mon_data/mon_L3_00/mbm_local_config >>> ./g2/mon_data/mon_L3_01/mbm_local_config >>> ./mon_groups/m2/mon_data/mon_L3_00/mbm_local_config >>> ./mon_groups/m2/mon_data/mon_L3_01/mbm_local_config >>> ./mon_groups/m1/mon_data/mon_L3_00/mbm_local_config >>> ./mon_groups/m1/mon_data/mon_L3_01/mbm_local_config >>> >>> >>> From what I understand, the following sysfs files are >>> associated with cache domain #0 and thus writing to any of these >>> files would change the same configuration: >>> ./mon_data/mon_L3_00/mbm_local_config >>> ./g2/mon_data/mon_L3_00/mbm_local_config >>> ./mon_groups/m2/mon_data/mon_L3_00/mbm_local_config >>> ./mon_groups/m1/mon_data/mon_L3_00/mbm_local_config >>> >>> Could you please correct me where I am wrong? >> For example, we have CPUs 0-7 in domain 0. We have two counters which are >> configurable. >> >> Lets consider same example as your mentioned about. >> >> g2 is a control group. >> >> m1 and m2 are monitor group. >> >> We can have control group g2 with CPUs 0-7 to limit the L3 bandwidth (or >> memory bandwidth with required schemata setting). >> >> We can have mon group m1 with cpus 0-3 to monitor mbm_local_bytes. >> >> We can have mon group m2 with cpus 4-7 to monitor mbm_total_bytes. >> >> Each group is independently, monitoring two separate thing. Without having > Right, because monitoring, the actual counting of the events, is per monitor > group. When a monitor group is created a new RMID is created and when the > counter is read it is per-RMID. > > The event configuration is independent from the RMID using the counter. > >> sysfs file (mbm_local_config and mbm_total_config) in each monitor group, >> we wont be able to configure the above configuration. > I do not understand this reasoning. From what I understand the > event configuration is independent from the monitoring group. Thus, changing > an event configuration for one monitoring group would impact all > monitoring groups using that event counter. This implementation associates > an event configuration with each monitoring group and by doing so it > implies that it is unique to the monitoring group, but that is not > how it works. The event configuration is designed per L3 domain. The mon_data is also per domain (like mon_L3_00.. mon_L3_01 etc). So, added the event configuration file inside each domain. We have all the information inside the domain. Thought, that is right place. I am open for suggestions. Thanks Babu
