Re: [RFC PATCH v3 11/17] x86/resctrl: Introduce mbm_total_cfg and mbm_local_cfg

Moger, Babu
2024-05-08T15:57:39Z

Hi Reinette,

On 5/3/24 18:33, Reinette Chatre wrote:
> Hi Babu,
>
> On 3/28/2024 6:06 PM, Babu Moger wrote:
>> If the BMEC (Bandwidth Monitoring Event Configuration) feature is
>> supported, the bandwidth events can be configured to track specific events.
>> The event configuration is domain specific. ABMC (Assignable Bandwidth
>> Monitoring Counters) feature needs event configuration information to
>> assign RMID to the hardware counter. Currently, this information is not
>> available.
>
> hmmm ... "Currently, this information is not available." does not sound
> accurate. Perhaps it can be made more specific with something like:
> "Event configurations are not stored in resctrl but instead always
> read from or written to hardware directly when prompted by user space."
> (feel free to improve)

ok. Sure

>
>>
>> Save the event configuration information in the rdt_hw_domain, so it can
>> be used while for RMID assignment.
>
> "be used while for RMID assignment" -> "be used for RMID assignment"?

Sure.

>
>>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>>
>> ---
>> v3: Minor changes related to rebase in mbm_config_write_domain.
>>
>> v2: No changes.
>> ---
>> arch/x86/kernel/cpu/resctrl/core.c | 2 ++
>> arch/x86/kernel/cpu/resctrl/internal.h | 3 +++
>> arch/x86/kernel/cpu/resctrl/monitor.c | 11 +++++++++++
>> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 16 +++++++++++++++-
>> 4 files changed, 31 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
>> index 50e9ec5e547b..ed4f6d49d737 100644
>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>> @@ -555,6 +555,8 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
>> return;
>> }
>>
>> + arch_domain_mbm_evt_config(hw_dom);
>> +
>> list_add_tail_rcu(&d->list, add_pos);
>>
>> err = resctrl_online_domain(r, d);
>> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
>> index 41b06d46ea74..88453c86474b 100644
>> --- a/arch/x86/kernel/cpu/resctrl/internal.h
>> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
>> @@ -385,6 +385,8 @@ struct rdt_hw_domain {
>> u32 *ctrl_val;
>> struct arch_mbm_state *arch_mbm_total;
>> struct arch_mbm_state *arch_mbm_local;
>> + u32 mbm_total_cfg;
>> + u32 mbm_local_cfg;
>
> (please fix tabs/spaces)

Ack.
>
>> };
>>
>> static inline struct rdt_hw_domain *resctrl_to_arch_dom(struct rdt_domain *r)
>> @@ -648,6 +650,7 @@ void __check_limbo(struct rdt_domain *d, bool force_free);
>> void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
>> void __init resctrl_file_fflags_init(const char *config,
>> unsigned long fflags);
>> +void arch_domain_mbm_evt_config(struct rdt_hw_domain *hw_dom);
>> void rdt_staged_configs_clear(void);
>> bool closid_allocated(unsigned int closid);
>> int resctrl_find_cleanest_closid(void);
>> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
>> index 56dc49021540..8677dbf6de43 100644
>> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
>> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
>> @@ -1090,3 +1090,14 @@ void __init intel_rdt_mbm_apply_quirk(void)
>> mbm_cf_rmidthreshold = mbm_cf_table[cf_index].rmidthreshold;
>> mbm_cf = mbm_cf_table[cf_index].cf;
>> }
>> +
>> +void arch_domain_mbm_evt_config(struct rdt_hw_domain *hw_dom)
>> +{
>> + if (mbm_total_event.configurable)
>> + hw_dom->mbm_total_cfg = MAX_EVT_CONFIG_BITS;
>> +
>> + if (mbm_local_event.configurable)
>> + hw_dom->mbm_local_cfg = READS_TO_LOCAL_MEM |
>> + NON_TEMP_WRITE_TO_LOCAL_MEM |
>> + READS_TO_LOCAL_S_MEM;
>> +}
>
> Shouldn't the defaults be discovered from hardware?

Yes. That is correct. We can read from the hardware.

--
Thanks
Babu Moger