linux-kernel - Re: [RFC v2 PATCH 6/7] x86/resctrl: Display the RMID and COSID for resctrl groups

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Message-ID: <0b42ee96-32cf-b929-6033-7898821b54cb@intel.com>
Date:   Thu, 16 Feb 2023 17:46:33 -0800
From:   Fenghua Yu <fenghua.yu@...el.com>
To:     Babu Moger <babu.moger@....com>, <reinette.chatre@...el.com>
CC:     <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
        <dave.hansen@...ux.intel.com>, <x86@...nel.org>, <hpa@...or.com>,
        <corbet@....net>, <linux-kernel@...r.kernel.org>,
        <linux-doc@...r.kernel.org>, <eranian@...gle.com>,
        <peternewman@...gle.com>
Subject: Re: [RFC v2 PATCH 6/7] x86/resctrl: Display the RMID and COSID for
 resctrl groups

Hi, Babu,

On 2/2/23 13:47, Babu Moger 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
> 
> 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 2c013c5d45fd..de332c242523 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

Capitals Resource Monitoring ID (RMID).

> +        utilization. Monitoring is performed by tagging each core(or
> +        thread) or process via a Resource Monitoring ID (RMID). Kernel

s/Resource Monitoring ID (RMID)/RMID/

> +        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 9b7813aa6baf..c35d91b04de6 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
>   
>   /*
> @@ -1844,6 +1876,18 @@ 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,
> +	},
> +	{
> +		.name		= "rmid",
> +		.mode		= 0444,
> +		.kf_ops		= &rdtgroup_kf_single_ops,
> +		.seq_show	= rdtgroup_rmid_show,
> +	},
>   
>   };
>   
> 
> 
Thanks.

-Fenghua