Hi Reinette,
On 2/5/2025 6:19 PM, Reinette Chatre wrote:
> Hi Babu,
>
> On 1/22/25 12:20 PM, Babu Moger wrote:
>> Provide the interface to display the number of monitoring counters
>> available for assignment in each domain when mbm_cntr_assign is enabled.
>
> "when mbm_cntr_assign is enabled" -> "when mbm_cntr_assign mode is enabled"?
Sure.
>
>>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>
>
>> ---
>> Documentation/arch/x86/resctrl.rst | 8 +++++
>> arch/x86/kernel/cpu/resctrl/monitor.c | 1 +
>> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 46 ++++++++++++++++++++++++++
>> 3 files changed, 55 insertions(+)
>>
>> diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
>> index 31ff764deeeb..99cae75559b0 100644
>> --- a/Documentation/arch/x86/resctrl.rst
>> +++ b/Documentation/arch/x86/resctrl.rst
>> @@ -299,6 +299,14 @@ with the following files:
>> memory bandwidth tracking to a single memory bandwidth event per
>> monitoring group.
>>
>> +"available_mbm_cntrs":
>> + The number of monitoring counters available for assignment in each
>> + domain when mbm_cntr_assign mode is enabled on the system.
>> + ::
>> +
>
> Documentation jumps in with some hardcoded values that may cause confusion.
> It looks to be missing something like (and looking back this also applies
> to "num_mbm_cntrs"):
> "For example, on a system with 30 available monitoring/(hardware?) counters in
> each of its L3 domains:"
Sure.
>
>
>> + # cat /sys/fs/resctrl/info/L3_MON/available_mbm_cntrs
>> + 0=30;1=30
>> +
>
>
>> "max_threshold_occupancy":
>> Read/write file provides the largest value (in
>> bytes) at which a previously used LLC_occupancy
>> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
>> index 6fe9e610e9a0..f2bf5b13465d 100644
>> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
>> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
>> @@ -1234,6 +1234,7 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
>> cpuid_count(0x80000020, 5, &eax, &ebx, &ecx, &edx);
>> r->mon.num_mbm_cntrs = (ebx & GENMASK(15, 0)) + 1;
>> resctrl_file_fflags_init("num_mbm_cntrs", RFTYPE_MON_INFO);
>> + resctrl_file_fflags_init("available_mbm_cntrs", RFTYPE_MON_INFO);
>> }
>> }
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 75a3b56996ca..2b86124c336b 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -888,6 +888,46 @@ static int resctrl_num_mbm_cntrs_show(struct kernfs_open_file *of,
>> return 0;
>> }
>>
>> +static int resctrl_available_mbm_cntrs_show(struct kernfs_open_file *of,
>> + struct seq_file *s, void *v)
>> +{
>> + struct rdt_resource *r = of->kn->parent->priv;
>> + struct rdt_mon_domain *dom;
>> + bool sep = false;
>> + u32 cntrs, i;
>> + int ret = 0;
>> +
>> + cpus_read_lock();
>> + mutex_lock(&rdtgroup_mutex);
>> +
>
> Missing rdt_last_cmd_clear()?
Yes.
>
>> + if (!resctrl_arch_mbm_cntr_assign_enabled(r)) {
>> + rdt_last_cmd_puts("mbm_cntr_assign mode is not enabled\n");
>> + ret = -EINVAL;
>> + goto unlock_cntrs_show;
>> + }
>> +
>> + list_for_each_entry(dom, &r->mon_domains, hdr.list) {
>> + if (sep)
>> + seq_puts(s, ";");
>
> The one character prints can be simplified with a seq_putc().
Sure.
seq_putc(s, ';');
>
>> +
>> + cntrs = 0;
>> + for (i = 0; i < r->mon.num_mbm_cntrs; i++) {
>> + if (!dom->cntr_cfg[i].rdtgrp)
>> + cntrs++;
>> + }
>> +
>> + seq_printf(s, "%d=%d", dom->hdr.id, cntrs);
>
> I expect cntrs to need %u?
Sure.
>
>> + sep = true;
>> + }
>> + seq_puts(s, "\n");
>> +
>> +unlock_cntrs_show:
>> + mutex_unlock(&rdtgroup_mutex);
>> + cpus_read_unlock();
>> +
>> + return ret;
>> +}
>> +
>> #ifdef CONFIG_PROC_CPU_RESCTRL
>>
>> /*
>> @@ -1916,6 +1956,12 @@ static struct rftype res_common_files[] = {
>> .kf_ops = &rdtgroup_kf_single_ops,
>> .seq_show = resctrl_num_mbm_cntrs_show,
>> },
>> + {
>> + .name = "available_mbm_cntrs",
>> + .mode = 0444,
>> + .kf_ops = &rdtgroup_kf_single_ops,
>> + .seq_show = resctrl_available_mbm_cntrs_show,
>> + },
>> {
>> .name = "cpus",
>> .mode = 0644,
>
> Reinette
>
Thanks
Babu