On Wed, Apr 16, 2025 at 12:09:52PM -0500, Moger, Babu wrote: > Hi Reinette, > > On 4/15/25 11:53, Reinette Chatre wrote: > > Hi Babu, > > > > On 4/15/25 7:20 AM, Moger, Babu wrote: > >> Hi Reinette, > >> > >> On 4/11/25 16:04, Reinette Chatre wrote: > >>> Hi Babu, > >>> > >>> On 4/3/25 5:18 PM, Babu Moger wrote: > >>>> The mbm_cntr_assign mode offers "num_mbm_cntrs" number of counters that > >>>> can be assigned to an RMID, event pair and monitor the bandwidth as long > >>>> as it is assigned. > >>> > >>> Above makes it sound as though multiple counters can be assigned to > >>> an RMID, event pair. > >>> > >> > >> Yes. Multiple counter-ids can be assigned to RMID, event pair. > > > > oh, are you referring to the assignments of different counters across multiple > > domains? > > May be I am confusing you here. This is what I meant. > > Here is one example. > > In a same group, > Configure cntr_id 0, to count reads only (This maps to total event). > Configure cntr_id 1, to count write only (This maps to local event). > Configure cntr_id 2, to count dirty victims. > so on.. > so on.. > Configure cntr_id 31, to count remote read only. > > We have 32 counter ids in a domain. Basically, we can configure all the > counters in a domain to just one group if you want to. > > We cannot do that right now because our data structures cannot do that. > We can only configure 2 events(local and total) right now. Not just data structures, but also user visible files in mon_data/mon_L3*/* You'd need to create a new file for each counter. My patch for making it easier to add more counters: https://lore.kernel.org/all/20250407234032.241215-3-tony.luck@xxxxxxxxx/ may help ... though you have to pick the number of simultaneous counters at compile time to size the arrays in the domain structures: struct mbm_state *mbm_states[QOS_NUM_MBM_EVENTS]; and if you are dynamically adding/removing events using the configuration files, need to alloc/free the memory that those arrays of pointers reference ... as well as adding/removing files from the appropriate mon_data/mon_L3* directory. > My understanding it is same with MPAM also. > > > > >> > >>>> > >>>> Add the functionality to allocate and assign the counters to RMID, event > >>>> pair in the domain. > >>> > >>> "assign *a* counter to an RMID, event pair"? > >> > >> Sure. > >> > >>> > >>>> > >>>> If all the counters are in use, the kernel will log the error message > >>>> "Unable to allocate counter in domain" in /sys/fs/resctrl/info/ > >>>> last_cmd_status when a new assignment is requested. Exit on the first > >>>> failure when assigning counters across all the domains. > >>>> > >>>> Signed-off-by: Babu Moger <babu.moger@xxxxxxx> > >>>> --- > >>> > >>> ... > >>> > >>>> --- > >>>> arch/x86/kernel/cpu/resctrl/internal.h | 2 + > >>>> arch/x86/kernel/cpu/resctrl/monitor.c | 124 +++++++++++++++++++++++++ > >>>> 2 files changed, 126 insertions(+) > >>>> > >>>> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h > >>>> index 0b73ec451d2c..1a8ac511241a 100644 > >>>> --- a/arch/x86/kernel/cpu/resctrl/internal.h > >>>> +++ b/arch/x86/kernel/cpu/resctrl/internal.h > >>>> @@ -574,6 +574,8 @@ bool closid_allocated(unsigned int closid); > >>>> int resctrl_find_cleanest_closid(void); > >>>> void arch_mbm_evt_config_init(struct rdt_hw_mon_domain *hw_dom); > >>>> unsigned int mon_event_config_index_get(u32 evtid); > >>>> +int resctrl_assign_cntr_event(struct rdt_resource *r, struct rdt_mon_domain *d, > >>>> + struct rdtgroup *rdtgrp, enum resctrl_event_id evtid, u32 evt_cfg); > >>> > >>> This is internal to resctrl fs. Why is it needed to provide both the event id > >>> and the event configuration? Event configuration can be determined from event ID? > >> > >> Yes. It can be done. Then I have to export the functions like > >> mbm_get_assign_config() into monitor.c. To avoid that I passed it from > >> here which I felt much more cleaner. > > > >>From what I can tell, for example by looking at patch #22, callers of > > resctrl_assign_cntr_event() now need to call mbm_get_assign_config() > > every time before calling resctrl_assign_cntr_event(). Calling > > mbm_get_assign_config() from within resctrl_assign_cntr_event() seems > > simpler to me and that may result in mbm_get_assign_config() moving to > > monitor.c as an extra benefit. > > Sure. > > > > > ... > > > >>>> +static int mbm_cntr_get(struct rdt_resource *r, struct rdt_mon_domain *d, > >>>> + struct rdtgroup *rdtgrp, enum resctrl_event_id evtid) > >>>> +{ > >>>> + int cntr_id; > >>>> + > >>>> + for (cntr_id = 0; cntr_id < r->mon.num_mbm_cntrs; cntr_id++) { > >>>> + if (d->cntr_cfg[cntr_id].rdtgrp == rdtgrp && > >>>> + d->cntr_cfg[cntr_id].evtid == evtid) > >>>> + return cntr_id; > >>>> + } > >>>> + > >>>> + return -ENOENT; > >>>> +} > >>>> + > >>>> +static int mbm_cntr_alloc(struct rdt_resource *r, struct rdt_mon_domain *d, > >>>> + struct rdtgroup *rdtgrp, enum resctrl_event_id evtid) > >>>> +{ > >>>> + int cntr_id; > >>>> + > >>>> + for (cntr_id = 0; cntr_id < r->mon.num_mbm_cntrs; cntr_id++) { > >>>> + if (!d->cntr_cfg[cntr_id].rdtgrp) { > >>>> + d->cntr_cfg[cntr_id].rdtgrp = rdtgrp; > >>>> + d->cntr_cfg[cntr_id].evtid = evtid; > >>>> + return cntr_id; > >>>> + } > >>>> + } > >>>> + > >>>> + return -ENOSPC; > >>>> +} > >>>> + > >>>> +static void mbm_cntr_free(struct rdt_mon_domain *d, int cntr_id) > >>>> +{ > >>>> + memset(&d->cntr_cfg[cntr_id], 0, sizeof(struct mbm_cntr_cfg)); > >>>> +} > >>>> + > >>>> +/* > >>>> + * Allocate a fresh counter and configure the event if not assigned already. > >>>> + */ > >>>> +static int resctrl_alloc_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d, > >>>> + struct rdtgroup *rdtgrp, enum resctrl_event_id evtid, > >>>> + u32 evt_cfg) > >>> > >>> Same here, why are both evtid and evt_cfg provided as arguments? > >> > >> Yes. It can be done. Then I have to export the functions like > >> mbm_get_assign_config() into monitor.c. To avoid that I passed it from > >> here which I felt much more cleaner. > > > > Maybe even resctrl_assign_cntr_event() does not need to call mbm_get_assign_config() > > but only resctrl_alloc_config_cntr() needs to call mbm_get_assign_config(). Doing so > > may avoid more burden on callers while reducing parameters needed throughout. > > > > ok. Sure. Will do. > > -- > Thanks > Babu Moger -Tony
