Date:   Mon, 20 Mar 2023 16:59:21 -0400
From:   Stephane Eranian <eranian@...gle.com>
To:     Babu Moger <babu.moger@....com>
Cc:     corbet@....net, reinette.chatre@...el.com, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, fenghua.yu@...el.com,
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        peterz@...radead.org, jpoimboe@...nel.org, pbonzini@...hat.com,
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Subject: Re: [PATCH v3 5/7] x86/resctrl: Display the RMID and COSID for
 resctrl groups

On Thu, Mar 2, 2023 at 3:25 PM Babu Moger <babu.moger@....com> wrote:
>
> When a user creates a control or monitor group, the CLOSID or RMID
> are not visible to the user. These are architecturally defined entities.
> There is no harm in displaying these in resctrl groups. Sometimes it
> can help to debug the issues.
>
> Add CLOSID and RMID to the control/monitor groups display in resctrl
> interface.
>
> $cat /sys/fs/resctrl/clos1/closid
> 1
> $cat /sys/fs/resctrl/mon_groups/mon1/rmid
> 3
>
Is the intent here to be x86 specific?
How would that work on ARM?
Shouldn't we be using more generic names such as monitoring_id,   control_id?


> Signed-off-by: Babu Moger <babu.moger@....com>
> ---
>  Documentation/x86/resctrl.rst          |   17 ++++++++++++
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |   44 ++++++++++++++++++++++++++++++++
>  2 files changed, 61 insertions(+)
>
> diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
> index 25203f20002d..67eae74fe40c 100644
> --- a/Documentation/x86/resctrl.rst
> +++ b/Documentation/x86/resctrl.rst
> @@ -321,6 +321,15 @@ All groups contain the following files:
>         Just like "cpus", only using ranges of CPUs instead of bitmasks.
>
>
> +"rmid":
> +       Available only with debug option.Reading this file shows the
> +       Resource Monitoring ID (RMID) for monitoring the resource
> +       utilization. Monitoring is performed by tagging each core (or
> +       thread) or process via a RMID. Kernel assigns a new RMID when
> +       a group is created depending on the available RMIDs. Multiple
> +       cores (or threads) or processes can share a same RMID in a resctrl
> +       domain.
> +
>  When control is enabled all CTRL_MON groups will also contain:
>
>  "schemata":
> @@ -342,6 +351,14 @@ When control is enabled all CTRL_MON groups will also contain:
>         file. On successful pseudo-locked region creation the mode will
>         automatically change to "pseudo-locked".
>
> +"closid":
> +       Available only with debug option. Reading this file shows the
> +       Class of Service (CLOS) id which acts as a resource control tag
> +       on which the resources can be throttled. Kernel assigns a new
> +       CLOSID a control group is created depending on the available
> +       CLOSIDs. Multiple cores(or threads) or processes can share a
> +       same CLOSID in a resctrl domain.
> +
>  When monitoring is enabled all MON groups will also contain:
>
>  "mon_data":
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 1eb538965bd3..389d64b42704 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -760,6 +760,38 @@ static int rdtgroup_tasks_show(struct kernfs_open_file *of,
>         return ret;
>  }
>
> +static int rdtgroup_closid_show(struct kernfs_open_file *of,
> +                               struct seq_file *s, void *v)
> +{
> +       struct rdtgroup *rdtgrp;
> +       int ret = 0;
> +
> +       rdtgrp = rdtgroup_kn_lock_live(of->kn);
> +       if (rdtgrp)
> +               seq_printf(s, "%u\n", rdtgrp->closid);
> +       else
> +               ret = -ENOENT;
> +       rdtgroup_kn_unlock(of->kn);
> +
> +       return ret;
> +}
> +
> +static int rdtgroup_rmid_show(struct kernfs_open_file *of,
> +                             struct seq_file *s, void *v)
> +{
> +       struct rdtgroup *rdtgrp;
> +       int ret = 0;
> +
> +       rdtgrp = rdtgroup_kn_lock_live(of->kn);
> +       if (rdtgrp)
> +               seq_printf(s, "%u\n", rdtgrp->mon.rmid);
> +       else
> +               ret = -ENOENT;
> +       rdtgroup_kn_unlock(of->kn);
> +
> +       return ret;
> +}
> +
>  #ifdef CONFIG_PROC_CPU_RESCTRL
>
>  /*
> @@ -1821,6 +1853,12 @@ static struct rftype res_common_files[] = {
>                 .seq_show       = rdtgroup_tasks_show,
>                 .fflags         = RFTYPE_BASE,
>         },
> +       {
> +               .name           = "rmid",
> +               .mode           = 0444,
> +               .kf_ops         = &rdtgroup_kf_single_ops,
> +               .seq_show       = rdtgroup_rmid_show,
> +       },
>         {
>                 .name           = "schemata",
>                 .mode           = 0644,
> @@ -1844,6 +1882,12 @@ static struct rftype res_common_files[] = {
>                 .seq_show       = rdtgroup_size_show,
>                 .fflags         = RFTYPE_BASE_CTRL,
>         },
> +       {
> +               .name           = "closid",
> +               .mode           = 0444,
> +               .kf_ops         = &rdtgroup_kf_single_ops,
> +               .seq_show       = rdtgroup_closid_show,
> +       },
>
>  };
>
>
>

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