[RFC PATCH 0/3] x86/resctrl: Miscellaneous resctrl features

[RFC PATCH 0/3] x86/resctrl: Miscellaneous resctrl features

[Babu Moger]

These series adds support for 3 minor features. 
1. Support assigning multiple tasks to control/mon groups
2. Detect and move task's threads automatically to the groups
3. Add RMID and CLOSID in resctrl inteface.

These feature requests are coming from our test team. They have
been asking me to add these features to QoS for a while. Please
review and comment if these changes make sense. Thanks

---

Babu Moger (3):
      x86/resctrl: Add multiple tasks to the resctrl group at once
      x86/resctrl: Move the task's threads to the group automatically
      x86/resctrl: Display the RMID and COSID for resctrl groups


 Documentation/x86/resctrl.rst          | 28 ++++++--
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 90 +++++++++++++++++++++++---
 2 files changed, 104 insertions(+), 14 deletions(-)

--

[RFC PATCH 1/3] x86/resctrl: Add multiple tasks to the resctrl group at once

[Babu Moger]

Right now, the resctrl task assignment for the MONITOR or CONTROL group
needs to be one at a time. For example:
  $mount -t resctrl resctrl /sys/fs/resctrl/
  $mkdir /sys/fs/resctrl/clos1
  $echo 123 > /sys/fs/resctrl/clos1/tasks
  $echo 456 > /sys/fs/resctrl/clos1/tasks
  $echo 789 > /sys/fs/resctrl/clos1/tasks

This is not user-friendly when dealing with hundreds of tasks.

Improve the user experience by supporting the multiple task assignment
in one command with tasks separated by commas. For example:
  $echo 123,456,789 > /sys/fs/resctrl/clos1/tasks

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 Documentation/x86/resctrl.rst          |   13 ++++++------
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |   35 ++++++++++++++++++++++++++------
 2 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
index 71a531061e4e..f26e16412bcb 100644
--- a/Documentation/x86/resctrl.rst
+++ b/Documentation/x86/resctrl.rst
@@ -208,12 +208,13 @@ All groups contain the following files:
 "tasks":
 	Reading this file shows the list of all tasks that belong to
 	this group. Writing a task id to the file will add a task to the
-	group. If the group is a CTRL_MON group the task is removed from
-	whichever previous CTRL_MON group owned the task and also from
-	any MON group that owned the task. If the group is a MON group,
-	then the task must already belong to the CTRL_MON parent of this
-	group. The task is removed from any previous MON group.
-
+	group. Multiple tasks can be assigned at once with each task
+	separated by commas. If the group is a CTRL_MON group the task
+	is removed from whichever previous CTRL_MON group owned the task
+	and also from any MON group that owned the task. If the group is
+	a MON group, then the task must already belong to the CTRL_MON
+	parent of this group. The task is removed from any previous MON
+	group.
 
 "cpus":
 	Reading this file shows a bitmask of the logical CPUs owned by
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index e5a48f05e787..344607853f4c 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -686,28 +686,49 @@ static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
 				    char *buf, size_t nbytes, loff_t off)
 {
 	struct rdtgroup *rdtgrp;
+	char *pid_str;
 	int ret = 0;
 	pid_t pid;
 
-	if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
+	/* Valid input requires a trailing newline */
+	if (nbytes == 0 || buf[nbytes - 1] != '\n')
 		return -EINVAL;
+
+	buf[nbytes - 1] = '\0';
+
+	cpus_read_lock();
 	rdtgrp = rdtgroup_kn_lock_live(of->kn);
 	if (!rdtgrp) {
-		rdtgroup_kn_unlock(of->kn);
-		return -ENOENT;
+		ret = -ENOENT;
+		goto exit;
+	}
+
+next:
+	if (!buf || buf[0] == '\0')
+		goto exit;
+
+	pid_str = strim(strsep(&buf, ","));
+
+	if (kstrtoint(pid_str, 0, &pid) || pid < 0) {
+		ret = -EINVAL;
+		goto exit;
 	}
+
 	rdt_last_cmd_clear();
 
 	if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED ||
-	    rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
-		ret = -EINVAL;
+			rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
 		rdt_last_cmd_puts("Pseudo-locking in progress\n");
-		goto unlock;
+		ret = -EINVAL;
+		goto exit;
 	}
 
 	ret = rdtgroup_move_task(pid, rdtgrp, of);
 
-unlock:
+	goto next;
+
+exit:
+	cpus_read_unlock();
 	rdtgroup_kn_unlock(of->kn);
 
 	return ret ?: nbytes;

[RFC PATCH 2/3] x86/resctrl: Move the task's threads to the group automatically

[Babu Moger]

Some micro benchmarks run multiple threads when started. Monitoring
(or controlling) the benchmark using the task id is bit tricky. Users
need to track all the threads and assign them individually to monitor
or control. For example:
  $stream_lowOverhead -codeAlg 13 -nRep 100000 -cores 0 1 2 3 -memMB 32
  -alignKB 8192 -aPadB 0 -bPadB 0 -cPadB 0 -testMask 1

  $pidof stream_lowOverhead
  6793

This benchmark actually runs multiple threads underneath on the cores
listed above. It can be seen with the command:
  $ps -T -p 6793
   PID   SPID TTY          TIME CMD
  6793   6793 pts/2    00:00:00 stream_lowOverh
  6793   6802 pts/2    00:01:25 stream_lowOverh
  6793   6803 pts/2    00:01:25 stream_lowOverh
  6793   6804 pts/2    00:01:25 stream_lowOverh
  6793   6805 pts/2    00:01:25 stream_lowOverh

Users need to assign these threads individually to the resctrl group for
monitoring or controlling.

  $echo 6793 > /sys/fs/restrl/clos1/tasks
  $echo 6802 > /sys/fs/restrl/clos1/tasks
  $echo 6803 > /sys/fs/restrl/clos1/tasks
  $echo 6804 > /sys/fs/restrl/clos1/tasks
  $echo 6805 > /sys/fs/restrl/clos1/tasks

That is not easy when dealing with numerous threads.

Detect the task's threads automatically and assign them to the resctrl
group when parent task is assigned. For example:
  $echo 6793 > /sys/fs/restrl/clos1/tasks

All the threads will be assigned to the group automatically.
  $cat /sys/fs/restrl/clos1/tasks
  6793
  6793
  6802
  6803
  6804
  6805

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 344607853f4c..0d71ed22cfa9 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -685,6 +685,7 @@ static int rdtgroup_move_task(pid_t pid, struct rdtgroup *rdtgrp,
 static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
 				    char *buf, size_t nbytes, loff_t off)
 {
+	struct task_struct *task, *thread;
 	struct rdtgroup *rdtgrp;
 	char *pid_str;
 	int ret = 0;
@@ -723,7 +724,13 @@ static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
 		goto exit;
 	}
 
-	ret = rdtgroup_move_task(pid, rdtgrp, of);
+	task = find_task_by_vpid(pid);
+	thread = task;
+	do {
+		ret = rdtgroup_move_task(thread->pid, rdtgrp, of);
+		if (ret)
+			goto exit;
+	} while_each_thread(task, thread);
 
 	goto next;
 

[RFC PATCH 3/3] x86/resctrl: Display the RMID and COSID for resctrl groups

[Babu Moger]

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@amd.com>
---
 Documentation/x86/resctrl.rst          |   15 ++++++++++
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |   46 ++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
index f26e16412bcb..8520514bc8b5 100644
--- a/Documentation/x86/resctrl.rst
+++ b/Documentation/x86/resctrl.rst
@@ -231,6 +231,14 @@ All groups contain the following files:
 	Just like "cpus", only using ranges of CPUs instead of bitmasks.
 
 
+"rmid":
+	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 Resource Monitoring
+	ID (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":
@@ -252,6 +260,13 @@ 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":
+	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 0d71ed22cfa9..98b4798e5cae 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -769,6 +769,38 @@ 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
 
 /*
@@ -1593,6 +1625,20 @@ static struct rftype res_common_files[] = {
 		.seq_show	= rdtgroup_size_show,
 		.fflags		= RF_CTRL_BASE,
 	},
+	{
+		.name		= "closid",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= rdtgroup_closid_show,
+		.fflags		= RF_CTRL_BASE,
+	},
+	{
+		.name		= "rmid",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= rdtgroup_rmid_show,
+		.fflags		= RFTYPE_BASE,
+	},
 
 };
 

RE: [RFC PATCH 1/3] x86/resctrl: Add multiple tasks to the resctrl group at once

[Yu, Fenghua]

Hi, Babu,

> Right now, the resctrl task assignment for the MONITOR or CONTROL group
> needs to be one at a time. For example:
>   $mount -t resctrl resctrl /sys/fs/resctrl/
>   $mkdir /sys/fs/resctrl/clos1
>   $echo 123 > /sys/fs/resctrl/clos1/tasks
>   $echo 456 > /sys/fs/resctrl/clos1/tasks
>   $echo 789 > /sys/fs/resctrl/clos1/tasks
> 
> This is not user-friendly when dealing with hundreds of tasks.
> 
> Improve the user experience by supporting the multiple task assignment in one
> command with tasks separated by commas. For example:
>   $echo 123,456,789 > /sys/fs/resctrl/clos1/tasks
> 
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---
>  Documentation/x86/resctrl.rst          |   13 ++++++------
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |   35 ++++++++++++++++++++++++++--
> ----
>  2 files changed, 35 insertions(+), 13 deletions(-)
> 
> diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
> index 71a531061e4e..f26e16412bcb 100644
> --- a/Documentation/x86/resctrl.rst
> +++ b/Documentation/x86/resctrl.rst
> @@ -208,12 +208,13 @@ All groups contain the following files:
>  "tasks":
>  	Reading this file shows the list of all tasks that belong to
>  	this group. Writing a task id to the file will add a task to the
> -	group. If the group is a CTRL_MON group the task is removed from
> -	whichever previous CTRL_MON group owned the task and also from
> -	any MON group that owned the task. If the group is a MON group,
> -	then the task must already belong to the CTRL_MON parent of this
> -	group. The task is removed from any previous MON group.
> -
> +	group. Multiple tasks can be assigned at once with each task
> +	separated by commas. If the group is a CTRL_MON group the task
> +	is removed from whichever previous CTRL_MON group owned the task
> +	and also from any MON group that owned the task. If the group is
> +	a MON group, then the task must already belong to the CTRL_MON
> +	parent of this group. The task is removed from any previous MON
> +	group.

Multiple tasks movement may fail in the middle. How to handle the failure
in the middle? Abort on all previous success movements?

Seems simple way is to exit from the failed task movement. That means
all previous successful movements will not be reversed and all tasks won't
be moved since the failure.

Then this info needs to be explained in the doc.
> 
>  "cpus":
>  	Reading this file shows a bitmask of the logical CPUs owned by diff --git
> a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index e5a48f05e787..344607853f4c 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -686,28 +686,49 @@ static ssize_t rdtgroup_tasks_write(struct
> kernfs_open_file *of,
>  				    char *buf, size_t nbytes, loff_t off)  {
>  	struct rdtgroup *rdtgrp;
> +	char *pid_str;
>  	int ret = 0;
>  	pid_t pid;
> 
> -	if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
> +	/* Valid input requires a trailing newline */
> +	if (nbytes == 0 || buf[nbytes - 1] != '\n')
>  		return -EINVAL;
> +
> +	buf[nbytes - 1] = '\0';
> +
> +	cpus_read_lock();
>  	rdtgrp = rdtgroup_kn_lock_live(of->kn);
>  	if (!rdtgrp) {
> -		rdtgroup_kn_unlock(of->kn);
> -		return -ENOENT;
> +		ret = -ENOENT;
> +		goto exit;
> +	}
> +
> +next:
> +	if (!buf || buf[0] == '\0')
> +		goto exit;
> +
> +	pid_str = strim(strsep(&buf, ","));
> +
> +	if (kstrtoint(pid_str, 0, &pid) || pid < 0) {
> +		ret = -EINVAL;

rdt_last_cmd_puts() to record the error.

> +		goto exit;
>  	}
> +
>  	rdt_last_cmd_clear();
> 
>  	if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED ||
> -	    rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
> -		ret = -EINVAL;
> +			rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
>  		rdt_last_cmd_puts("Pseudo-locking in progress\n");
> -		goto unlock;
> +		ret = -EINVAL;
> +		goto exit;
>  	}
> 
>  	ret = rdtgroup_move_task(pid, rdtgrp, of);

Do you want to exit if there is error in rdtgroup_move_task()?
Otherwise, the failure won't be captured if later take movement succeeds.

> 
> -unlock:
> +	goto next;
> +
> +exit:
> +	cpus_read_unlock();
>  	rdtgroup_kn_unlock(of->kn);
> 
>  	return ret ?: nbytes;
> 

Thanks.

-Fenghua

RE: [RFC PATCH 2/3] x86/resctrl: Move the task's threads to the group automatically

[Yu, Fenghua]

Hi, Babu,

> Some micro benchmarks run multiple threads when started. Monitoring (or
> controlling) the benchmark using the task id is bit tricky. Users need to track all
> the threads and assign them individually to monitor or control. For example:
>   $stream_lowOverhead -codeAlg 13 -nRep 100000 -cores 0 1 2 3 -memMB 32
>   -alignKB 8192 -aPadB 0 -bPadB 0 -cPadB 0 -testMask 1
> 
>   $pidof stream_lowOverhead
>   6793
> 
> This benchmark actually runs multiple threads underneath on the cores listed
> above. It can be seen with the command:
>   $ps -T -p 6793
>    PID   SPID TTY          TIME CMD
>   6793   6793 pts/2    00:00:00 stream_lowOverh
>   6793   6802 pts/2    00:01:25 stream_lowOverh
>   6793   6803 pts/2    00:01:25 stream_lowOverh
>   6793   6804 pts/2    00:01:25 stream_lowOverh
>   6793   6805 pts/2    00:01:25 stream_lowOverh
> 
> Users need to assign these threads individually to the resctrl group for
> monitoring or controlling.
> 
>   $echo 6793 > /sys/fs/restrl/clos1/tasks
>   $echo 6802 > /sys/fs/restrl/clos1/tasks
>   $echo 6803 > /sys/fs/restrl/clos1/tasks
>   $echo 6804 > /sys/fs/restrl/clos1/tasks
>   $echo 6805 > /sys/fs/restrl/clos1/tasks
> 
> That is not easy when dealing with numerous threads.
> 
> Detect the task's threads automatically and assign them to the resctrl group
> when parent task is assigned. For example:

But user may choose not to move threads along with the parent.
You will need to have an option to opt in.

>   $echo 6793 > /sys/fs/restrl/clos1/tasks
> 
> All the threads will be assigned to the group automatically.
>   $cat /sys/fs/restrl/clos1/tasks
>   6793
>   6793
>   6802
>   6803
>   6804
>   6805
> 
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |    9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 344607853f4c..0d71ed22cfa9 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -685,6 +685,7 @@ static int rdtgroup_move_task(pid_t pid, struct rdtgroup
> *rdtgrp,  static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
>  				    char *buf, size_t nbytes, loff_t off)  {
> +	struct task_struct *task, *thread;
>  	struct rdtgroup *rdtgrp;
>  	char *pid_str;
>  	int ret = 0;
> @@ -723,7 +724,13 @@ static ssize_t rdtgroup_tasks_write(struct
> kernfs_open_file *of,
>  		goto exit;
>  	}
> 
> -	ret = rdtgroup_move_task(pid, rdtgrp, of);
> +	task = find_task_by_vpid(pid);
> +	thread = task;
> +	do {
> +		ret = rdtgroup_move_task(thread->pid, rdtgrp, of);
> +		if (ret)
> +			goto exit;

If failure happens in the middle of threads, will you reverse the previous
moved threads (or even the task) or will you report this failure and move
to the next thread? Seems to me you need to either move all threads or
no thread moved at all.

> +	} while_each_thread(task, thread);
> 
>  	goto next;
> 
> 
Thanks.

-Fenghua

RE: [RFC PATCH 3/3] x86/resctrl: Display the RMID and COSID for resctrl groups

[Yu, Fenghua]

Hi, Babu,

> 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.
Although "no harm" to show them, it's not useful for generic user either and may
cause confusion sometimes. CLOSID and RMID are supposed to be invisible to
generic users.

Maybe introduce a new resctrl mount option called "debug" and show the files
and maybe other future debug info only in debug mode?

> 
> 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@amd.com>
> ---
>  Documentation/x86/resctrl.rst          |   15 ++++++++++
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |   46
> ++++++++++++++++++++++++++++++++
>  2 files changed, 61 insertions(+)
> 
> diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
> index f26e16412bcb..8520514bc8b5 100644
> --- a/Documentation/x86/resctrl.rst
> +++ b/Documentation/x86/resctrl.rst
> @@ -231,6 +231,14 @@ All groups contain the following files:
>  	Just like "cpus", only using ranges of CPUs instead of bitmasks.
> 
> 
> +"rmid":
> +	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 Resource Monitoring
> +	ID (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":
> @@ -252,6 +260,13 @@ 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":
> +	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 0d71ed22cfa9..98b4798e5cae 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -769,6 +769,38 @@ 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
> 
>  /*
> @@ -1593,6 +1625,20 @@ static struct rftype res_common_files[] = {
>  		.seq_show	= rdtgroup_size_show,
>  		.fflags		= RF_CTRL_BASE,
>  	},
> +	{
> +		.name		= "closid",
> +		.mode		= 0444,
> +		.kf_ops		= &rdtgroup_kf_single_ops,
> +		.seq_show	= rdtgroup_closid_show,
> +		.fflags		= RF_CTRL_BASE,
> +	},
> +	{
> +		.name		= "rmid",
> +		.mode		= 0444,
> +		.kf_ops		= &rdtgroup_kf_single_ops,
> +		.seq_show	= rdtgroup_rmid_show,
> +		.fflags		= RFTYPE_BASE,
> +	},
> 
>  };
> 
> 
Thanks.

-Fenghua

Re: [RFC PATCH 3/3] x86/resctrl: Display the RMID and COSID for resctrl groups

[Stephane Eranian]

On Tue, Jan 3, 2023 at 10:06 PM Yu, Fenghua <fenghua.yu@intel.com> wrote:
>
> Hi, Babu,
>
> > 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.
> Although "no harm" to show them, it's not useful for generic user either and may
> cause confusion sometimes. CLOSID and RMID are supposed to be invisible to
> generic users.
>
> Maybe introduce a new resctrl mount option called "debug" and show the files
> and maybe other future debug info only in debug mode?
>
On other non-x86 architectures, these have no meaning or no direct mapping.
Take ARM MPAM, it is called PARTID and it does not map to either RMID
or CLOSID, it is combined.
Why would you call this closid/rmid at the user level?
You could instead use a more generic name such as mon_hw_id,
ctrl_hw_id. And on ARM they would be the same.
Just my suggestion.


>
> >
> > 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@amd.com>
> > ---
> >  Documentation/x86/resctrl.rst          |   15 ++++++++++
> >  arch/x86/kernel/cpu/resctrl/rdtgroup.c |   46
> > ++++++++++++++++++++++++++++++++
> >  2 files changed, 61 insertions(+)
> >
> > diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
> > index f26e16412bcb..8520514bc8b5 100644
> > --- a/Documentation/x86/resctrl.rst
> > +++ b/Documentation/x86/resctrl.rst
> > @@ -231,6 +231,14 @@ All groups contain the following files:
> >       Just like "cpus", only using ranges of CPUs instead of bitmasks.
> >
> >
> > +"rmid":
> > +     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 Resource Monitoring
> > +     ID (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":
> > @@ -252,6 +260,13 @@ 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":
> > +     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 0d71ed22cfa9..98b4798e5cae 100644
> > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > @@ -769,6 +769,38 @@ 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
> >
> >  /*
> > @@ -1593,6 +1625,20 @@ static struct rftype res_common_files[] = {
> >               .seq_show       = rdtgroup_size_show,
> >               .fflags         = RF_CTRL_BASE,
> >       },
> > +     {
> > +             .name           = "closid",
> > +             .mode           = 0444,
> > +             .kf_ops         = &rdtgroup_kf_single_ops,
> > +             .seq_show       = rdtgroup_closid_show,
> > +             .fflags         = RF_CTRL_BASE,
> > +     },
> > +     {
> > +             .name           = "rmid",
> > +             .mode           = 0444,
> > +             .kf_ops         = &rdtgroup_kf_single_ops,
> > +             .seq_show       = rdtgroup_rmid_show,
> > +             .fflags         = RFTYPE_BASE,
> > +     },
> >
> >  };
> >
> >
> Thanks.
>
> -Fenghua

Re: [RFC PATCH 2/3] x86/resctrl: Move the task's threads to the group automatically

[Reinette Chatre]

Hi Babu,

On 1/3/2023 2:06 PM, Babu Moger wrote:
> Some micro benchmarks run multiple threads when started. Monitoring
> (or controlling) the benchmark using the task id is bit tricky. Users
> need to track all the threads and assign them individually to monitor
> or control. For example:
>   $stream_lowOverhead -codeAlg 13 -nRep 100000 -cores 0 1 2 3 -memMB 32
>   -alignKB 8192 -aPadB 0 -bPadB 0 -cPadB 0 -testMask 1
> 
>   $pidof stream_lowOverhead
>   6793
>
> This benchmark actually runs multiple threads underneath on the cores
> listed above. It can be seen with the command:
>   $ps -T -p 6793
>    PID   SPID TTY          TIME CMD
>   6793   6793 pts/2    00:00:00 stream_lowOverh
>   6793   6802 pts/2    00:01:25 stream_lowOverh
>   6793   6803 pts/2    00:01:25 stream_lowOverh
>   6793   6804 pts/2    00:01:25 stream_lowOverh
>   6793   6805 pts/2    00:01:25 stream_lowOverh
> 
> Users need to assign these threads individually to the resctrl group for
> monitoring or controlling.
> 
>   $echo 6793 > /sys/fs/restrl/clos1/tasks
>   $echo 6802 > /sys/fs/restrl/clos1/tasks
>   $echo 6803 > /sys/fs/restrl/clos1/tasks
>   $echo 6804 > /sys/fs/restrl/clos1/tasks
>   $echo 6805 > /sys/fs/restrl/clos1/tasks
> 
> That is not easy when dealing with numerous threads.

How about:

# echo $$ > /sys/fs/resctrl/clos1/tasks
# stream_lowOverhead -codeAlg 13 -nRep 100000 -cores 0 1 2 3 -memMB 32\
   -alignKB 8192 -aPadB 0 -bPadB 0 -cPadB 0 -testMask 1


Reinette

Re: [RFC PATCH 1/3] x86/resctrl: Add multiple tasks to the resctrl group at once

[Moger, Babu]

Hi Fenghua,

On 1/3/23 23:46, Yu, Fenghua wrote:
> Hi, Babu,
>
>> Right now, the resctrl task assignment for the MONITOR or CONTROL group
>> needs to be one at a time. For example:
>>   $mount -t resctrl resctrl /sys/fs/resctrl/
>>   $mkdir /sys/fs/resctrl/clos1
>>   $echo 123 > /sys/fs/resctrl/clos1/tasks
>>   $echo 456 > /sys/fs/resctrl/clos1/tasks
>>   $echo 789 > /sys/fs/resctrl/clos1/tasks
>>
>> This is not user-friendly when dealing with hundreds of tasks.
>>
>> Improve the user experience by supporting the multiple task assignment in one
>> command with tasks separated by commas. For example:
>>   $echo 123,456,789 > /sys/fs/resctrl/clos1/tasks
>>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>>  Documentation/x86/resctrl.rst          |   13 ++++++------
>>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |   35 ++++++++++++++++++++++++++--
>> ----
>>  2 files changed, 35 insertions(+), 13 deletions(-)
>>
>> diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
>> index 71a531061e4e..f26e16412bcb 100644
>> --- a/Documentation/x86/resctrl.rst
>> +++ b/Documentation/x86/resctrl.rst
>> @@ -208,12 +208,13 @@ All groups contain the following files:
>>  "tasks":
>>  	Reading this file shows the list of all tasks that belong to
>>  	this group. Writing a task id to the file will add a task to the
>> -	group. If the group is a CTRL_MON group the task is removed from
>> -	whichever previous CTRL_MON group owned the task and also from
>> -	any MON group that owned the task. If the group is a MON group,
>> -	then the task must already belong to the CTRL_MON parent of this
>> -	group. The task is removed from any previous MON group.
>> -
>> +	group. Multiple tasks can be assigned at once with each task
>> +	separated by commas. If the group is a CTRL_MON group the task
>> +	is removed from whichever previous CTRL_MON group owned the task
>> +	and also from any MON group that owned the task. If the group is
>> +	a MON group, then the task must already belong to the CTRL_MON
>> +	parent of this group. The task is removed from any previous MON
>> +	group.
> Multiple tasks movement may fail in the middle. How to handle the failure
> in the middle? Abort on all previous success movements?
>
> Seems simple way is to exit from the failed task movement. That means
> all previous successful movements will not be reversed and all tasks won't
> be moved since the failure.

Yes. That is what even I am thinking. Exit on a failed movement and record
the error. Don't need to reverse the successful movements.

>
> Then this info needs to be explained in the doc.
Sure.
>>  "cpus":
>>  	Reading this file shows a bitmask of the logical CPUs owned by diff --git
>> a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index e5a48f05e787..344607853f4c 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -686,28 +686,49 @@ static ssize_t rdtgroup_tasks_write(struct
>> kernfs_open_file *of,
>>  				    char *buf, size_t nbytes, loff_t off)  {
>>  	struct rdtgroup *rdtgrp;
>> +	char *pid_str;
>>  	int ret = 0;
>>  	pid_t pid;
>>
>> -	if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
>> +	/* Valid input requires a trailing newline */
>> +	if (nbytes == 0 || buf[nbytes - 1] != '\n')
>>  		return -EINVAL;
>> +
>> +	buf[nbytes - 1] = '\0';
>> +
>> +	cpus_read_lock();
>>  	rdtgrp = rdtgroup_kn_lock_live(of->kn);
>>  	if (!rdtgrp) {
>> -		rdtgroup_kn_unlock(of->kn);
>> -		return -ENOENT;
>> +		ret = -ENOENT;
>> +		goto exit;
>> +	}
>> +
>> +next:
>> +	if (!buf || buf[0] == '\0')
>> +		goto exit;
>> +
>> +	pid_str = strim(strsep(&buf, ","));
>> +
>> +	if (kstrtoint(pid_str, 0, &pid) || pid < 0) {
>> +		ret = -EINVAL;
> rdt_last_cmd_puts() to record the error.
Sure.
>
>> +		goto exit;
>>  	}
>> +
>>  	rdt_last_cmd_clear();
>>
>>  	if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED ||
>> -	    rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
>> -		ret = -EINVAL;
>> +			rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
>>  		rdt_last_cmd_puts("Pseudo-locking in progress\n");
>> -		goto unlock;
>> +		ret = -EINVAL;
>> +		goto exit;
>>  	}
>>
>>  	ret = rdtgroup_move_task(pid, rdtgrp, of);
> Do you want to exit if there is error in rdtgroup_move_task()?
> Otherwise, the failure won't be captured if later take movement succeeds.

Yes, that makes more sense. Exit on a failed movement and record the error.

Thanks

Babu

>
>> -unlock:
>> +	goto next;
>> +
>> +exit:
>> +	cpus_read_unlock();
>>  	rdtgroup_kn_unlock(of->kn);
>>
>>  	return ret ?: nbytes;
>>
> Thanks.
>
> -Fenghua

-- 
Thanks
Babu Moger

Re: [RFC PATCH 2/3] x86/resctrl: Move the task's threads to the group automatically

[Moger, Babu]

Hi Fenghua,

On 1/3/23 23:55, Yu, Fenghua wrote:
> Hi, Babu,
>
>> Some micro benchmarks run multiple threads when started. Monitoring (or
>> controlling) the benchmark using the task id is bit tricky. Users need to track all
>> the threads and assign them individually to monitor or control. For example:
>>   $stream_lowOverhead -codeAlg 13 -nRep 100000 -cores 0 1 2 3 -memMB 32
>>   -alignKB 8192 -aPadB 0 -bPadB 0 -cPadB 0 -testMask 1
>>
>>   $pidof stream_lowOverhead
>>   6793
>>
>> This benchmark actually runs multiple threads underneath on the cores listed
>> above. It can be seen with the command:
>>   $ps -T -p 6793
>>    PID   SPID TTY          TIME CMD
>>   6793   6793 pts/2    00:00:00 stream_lowOverh
>>   6793   6802 pts/2    00:01:25 stream_lowOverh
>>   6793   6803 pts/2    00:01:25 stream_lowOverh
>>   6793   6804 pts/2    00:01:25 stream_lowOverh
>>   6793   6805 pts/2    00:01:25 stream_lowOverh
>>
>> Users need to assign these threads individually to the resctrl group for
>> monitoring or controlling.
>>
>>   $echo 6793 > /sys/fs/restrl/clos1/tasks
>>   $echo 6802 > /sys/fs/restrl/clos1/tasks
>>   $echo 6803 > /sys/fs/restrl/clos1/tasks
>>   $echo 6804 > /sys/fs/restrl/clos1/tasks
>>   $echo 6805 > /sys/fs/restrl/clos1/tasks
>>
>> That is not easy when dealing with numerous threads.
>>
>> Detect the task's threads automatically and assign them to the resctrl group
>> when parent task is assigned. For example:
> But user may choose not to move threads along with the parent.
> You will need to have an option to opt in.
Yes. I agree.
>
>>   $echo 6793 > /sys/fs/restrl/clos1/tasks
>>
>> All the threads will be assigned to the group automatically.
>>   $cat /sys/fs/restrl/clos1/tasks
>>   6793
>>   6793
>>   6802
>>   6803
>>   6804
>>   6805
>>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |    9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 344607853f4c..0d71ed22cfa9 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -685,6 +685,7 @@ static int rdtgroup_move_task(pid_t pid, struct rdtgroup
>> *rdtgrp,  static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
>>  				    char *buf, size_t nbytes, loff_t off)  {
>> +	struct task_struct *task, *thread;
>>  	struct rdtgroup *rdtgrp;
>>  	char *pid_str;
>>  	int ret = 0;
>> @@ -723,7 +724,13 @@ static ssize_t rdtgroup_tasks_write(struct
>> kernfs_open_file *of,
>>  		goto exit;
>>  	}
>>
>> -	ret = rdtgroup_move_task(pid, rdtgrp, of);
>> +	task = find_task_by_vpid(pid);
>> +	thread = task;
>> +	do {
>> +		ret = rdtgroup_move_task(thread->pid, rdtgrp, of);
>> +		if (ret)
>> +			goto exit;
> If failure happens in the middle of threads, will you reverse the previous
> moved threads (or even the task) or will you report this failure and move
> to the next thread? Seems to me you need to either move all threads or
> no thread moved at all.

Yes. We should handle the failures properly.  Reversing all previous
movements requires quite a bit of book keeping.

As a work-around Reinette's comment "echo $$ >
/sys/fs/resctrl/clos1/tasks" seems to move all the threads.

I will have to think about this more closely.

Thanks

Babu


>
>> +	} while_each_thread(task, thread);
>>
>>  	goto next;
>>
>>
> Thanks.
>
> -Fenghua

-- 
Thanks
Babu Moger

Re: [RFC PATCH 3/3] x86/resctrl: Display the RMID and COSID for resctrl groups

[Moger, Babu]

Hi Fenghua,

On 1/4/23 00:06, Yu, Fenghua wrote:
> Hi, Babu,
>
>> 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.
> Although "no harm" to show them, it's not useful for generic user either and may
> cause confusion sometimes. CLOSID and RMID are supposed to be invisible to
> generic users.
>
> Maybe introduce a new resctrl mount option called "debug" and show the files
> and maybe other future debug info only in debug mode?

Actually, test team feels very strongly about this. Whenever there is some
issue, first question is what is the rmid or closid are you running on? We
normally don't have an answer for that.

In my opinion, adding debug mode just for these two fields seems way overkill.

Thanks

Babu


>
>> 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@amd.com>
>> ---
>>  Documentation/x86/resctrl.rst          |   15 ++++++++++
>>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |   46
>> ++++++++++++++++++++++++++++++++
>>  2 files changed, 61 insertions(+)
>>
>> diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
>> index f26e16412bcb..8520514bc8b5 100644
>> --- a/Documentation/x86/resctrl.rst
>> +++ b/Documentation/x86/resctrl.rst
>> @@ -231,6 +231,14 @@ All groups contain the following files:
>>  	Just like "cpus", only using ranges of CPUs instead of bitmasks.
>>
>>
>> +"rmid":
>> +	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 Resource Monitoring
>> +	ID (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":
>> @@ -252,6 +260,13 @@ 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":
>> +	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 0d71ed22cfa9..98b4798e5cae 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -769,6 +769,38 @@ 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
>>
>>  /*
>> @@ -1593,6 +1625,20 @@ static struct rftype res_common_files[] = {
>>  		.seq_show	= rdtgroup_size_show,
>>  		.fflags		= RF_CTRL_BASE,
>>  	},
>> +	{
>> +		.name		= "closid",
>> +		.mode		= 0444,
>> +		.kf_ops		= &rdtgroup_kf_single_ops,
>> +		.seq_show	= rdtgroup_closid_show,
>> +		.fflags		= RF_CTRL_BASE,
>> +	},
>> +	{
>> +		.name		= "rmid",
>> +		.mode		= 0444,
>> +		.kf_ops		= &rdtgroup_kf_single_ops,
>> +		.seq_show	= rdtgroup_rmid_show,
>> +		.fflags		= RFTYPE_BASE,
>> +	},
>>
>>  };
>>
>>
> Thanks.
>
> -Fenghua

-- 
Thanks
Babu Moger

Re: [RFC PATCH 3/3] x86/resctrl: Display the RMID and COSID for resctrl groups

[Moger, Babu]

Hi Stephane,

On 1/4/23 00:45, Stephane Eranian wrote:
> On Tue, Jan 3, 2023 at 10:06 PM Yu, Fenghua <fenghua.yu@intel.com> wrote:
>> Hi, Babu,
>>
>>> 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.
>> Although "no harm" to show them, it's not useful for generic user either and may
>> cause confusion sometimes. CLOSID and RMID are supposed to be invisible to
>> generic users.
>>
>> Maybe introduce a new resctrl mount option called "debug" and show the files
>> and maybe other future debug info only in debug mode?
>>
> On other non-x86 architectures, these have no meaning or no direct mapping.
> Take ARM MPAM, it is called PARTID and it does not map to either RMID
> or CLOSID, it is combined.
> Why would you call this closid/rmid at the user level?
> You could instead use a more generic name such as mon_hw_id,
> ctrl_hw_id. And on ARM they would be the same.
> Just my suggestion.

Sure. We can change the names to mon_hw_id and ctrl_hw_id.

Thanks

Babu


>
>
>>> 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@amd.com>
>>> ---
>>>  Documentation/x86/resctrl.rst          |   15 ++++++++++
>>>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |   46
>>> ++++++++++++++++++++++++++++++++
>>>  2 files changed, 61 insertions(+)
>>>
>>> diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
>>> index f26e16412bcb..8520514bc8b5 100644
>>> --- a/Documentation/x86/resctrl.rst
>>> +++ b/Documentation/x86/resctrl.rst
>>> @@ -231,6 +231,14 @@ All groups contain the following files:
>>>       Just like "cpus", only using ranges of CPUs instead of bitmasks.
>>>
>>>
>>> +"rmid":
>>> +     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 Resource Monitoring
>>> +     ID (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":
>>> @@ -252,6 +260,13 @@ 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":
>>> +     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 0d71ed22cfa9..98b4798e5cae 100644
>>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>>> @@ -769,6 +769,38 @@ 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
>>>
>>>  /*
>>> @@ -1593,6 +1625,20 @@ static struct rftype res_common_files[] = {
>>>               .seq_show       = rdtgroup_size_show,
>>>               .fflags         = RF_CTRL_BASE,
>>>       },
>>> +     {
>>> +             .name           = "closid",
>>> +             .mode           = 0444,
>>> +             .kf_ops         = &rdtgroup_kf_single_ops,
>>> +             .seq_show       = rdtgroup_closid_show,
>>> +             .fflags         = RF_CTRL_BASE,
>>> +     },
>>> +     {
>>> +             .name           = "rmid",
>>> +             .mode           = 0444,
>>> +             .kf_ops         = &rdtgroup_kf_single_ops,
>>> +             .seq_show       = rdtgroup_rmid_show,
>>> +             .fflags         = RFTYPE_BASE,
>>> +     },
>>>
>>>  };
>>>
>>>
>> Thanks.
>>
>> -Fenghua

-- 
Thanks
Babu Moger

Re: [RFC PATCH 2/3] x86/resctrl: Move the task's threads to the group automatically

[Moger, Babu]

Hi Reinette,

On 1/4/23 10:43, Reinette Chatre wrote:
> Hi Babu,
>
> On 1/3/2023 2:06 PM, Babu Moger wrote:
>> Some micro benchmarks run multiple threads when started. Monitoring
>> (or controlling) the benchmark using the task id is bit tricky. Users
>> need to track all the threads and assign them individually to monitor
>> or control. For example:
>>   $stream_lowOverhead -codeAlg 13 -nRep 100000 -cores 0 1 2 3 -memMB 32
>>   -alignKB 8192 -aPadB 0 -bPadB 0 -cPadB 0 -testMask 1
>>
>>   $pidof stream_lowOverhead
>>   6793
>>
>> This benchmark actually runs multiple threads underneath on the cores
>> listed above. It can be seen with the command:
>>   $ps -T -p 6793
>>    PID   SPID TTY          TIME CMD
>>   6793   6793 pts/2    00:00:00 stream_lowOverh
>>   6793   6802 pts/2    00:01:25 stream_lowOverh
>>   6793   6803 pts/2    00:01:25 stream_lowOverh
>>   6793   6804 pts/2    00:01:25 stream_lowOverh
>>   6793   6805 pts/2    00:01:25 stream_lowOverh
>>
>> Users need to assign these threads individually to the resctrl group for
>> monitoring or controlling.
>>
>>   $echo 6793 > /sys/fs/restrl/clos1/tasks
>>   $echo 6802 > /sys/fs/restrl/clos1/tasks
>>   $echo 6803 > /sys/fs/restrl/clos1/tasks
>>   $echo 6804 > /sys/fs/restrl/clos1/tasks
>>   $echo 6805 > /sys/fs/restrl/clos1/tasks
>>
>> That is not easy when dealing with numerous threads.
> How about:
>
> # echo $$ > /sys/fs/resctrl/clos1/tasks
> # stream_lowOverhead -codeAlg 13 -nRep 100000 -cores 0 1 2 3 -memMB 32\
>    -alignKB 8192 -aPadB 0 -bPadB 0 -cPadB 0 -testMask 1

Yes, That works. We can use that as a work-around for now.

I will drop this patch for now. I will have to figure out how to handle
failures in the middle of task/thread movement.

Will have to revisit this in the future. Will re-submit patch 1 and 3.

Thanks

Babu


>
> Reinette

-- 
Thanks
Babu Moger

RE: [RFC PATCH 3/3] x86/resctrl: Display the RMID and COSID for resctrl groups

[Yu, Fenghua]

Hi, Babu,

> >> 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.
> > Although "no harm" to show them, it's not useful for generic user
> > either and may cause confusion sometimes. CLOSID and RMID are supposed
> > to be invisible to generic users.
> >
> > Maybe introduce a new resctrl mount option called "debug" and show the
> > files and maybe other future debug info only in debug mode?
> 
> Actually, test team feels very strongly about this. Whenever there is some issue,
> first question is what is the rmid or closid are you running on? We normally don't
> have an answer for that.
> 
> In my opinion, adding debug mode just for these two fields seems way overkill.

Yes, they are useful for "test team" (quoted from your statement) and developers.
Not for end users.

A debug mode is useful not just for these two files. I'm working on another resctrl
project where much more complex hardware info needs to be dumped for debug purpose
only. It's obvious not to show it in generic use. It's more obvious to just show the info file in
debug mode in my case.

I think these CLOSID and RMID files and future debug files belong to a new debug mode.
It would be better to introduce the debug mode now rather than later so that it can be extended
easily in the future.

Maybe we can enable debug mode in a separate debug mode patch:
1. Add RFTYPE_DEBUG as a new file type. Files with this flag are for debug purpose and only be visible in\
    debug mode.
2. Add RFTYPE_INVISIBLE as a new file type. Files with this flag will be invisible/not be added in resctrl fs.
3. Add mount parameter "debug" so that ctx->debug=true if mount -o debug is given.
4. If ctx->debug is true, in rdt_enable_ctx(), go through RFTYPE_DEBUG files in res_common_files[] and mark
    fflags with RFTYPE_INVISIBLE.
5. In rdtgroup_add_file(), if (rft->fflags & RFTYPE_INVISIBLE) return. So the debug files will be visible only
    in debug mode.

With the debug mode patch in place, it's simple to extend to any debug files:
In your case, update this patch by just adding RFTYPE_DEBUG in fflags. Then the debug mode will work
for this patch automatically.
In my case or any future debug files, we just simply add RFTYPE_DEBUG in fflags and the debug mode will
work automatically.

Does it make sense?

Thanks.

-Fenghua

Re: [RFC PATCH 3/3] x86/resctrl: Display the RMID and COSID for resctrl groups

[Moger, Babu]

Hi Fenghua,

On 1/4/23 17:54, Yu, Fenghua wrote:
> Hi, Babu,
>
>>>> 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.
>>> Although "no harm" to show them, it's not useful for generic user
>>> either and may cause confusion sometimes. CLOSID and RMID are supposed
>>> to be invisible to generic users.
>>>
>>> Maybe introduce a new resctrl mount option called "debug" and show the
>>> files and maybe other future debug info only in debug mode?
>> Actually, test team feels very strongly about this. Whenever there is some issue,
>> first question is what is the rmid or closid are you running on? We normally don't
>> have an answer for that.
>>
>> In my opinion, adding debug mode just for these two fields seems way overkill.
> Yes, they are useful for "test team" (quoted from your statement) and developers.
> Not for end users.
>
> A debug mode is useful not just for these two files. I'm working on another resctrl
> project where much more complex hardware info needs to be dumped for debug purpose
> only. It's obvious not to show it in generic use. It's more obvious to just show the info file in
> debug mode in my case.
>
> I think these CLOSID and RMID files and future debug files belong to a new debug mode.
> It would be better to introduce the debug mode now rather than later so that it can be extended
> easily in the future.
>
> Maybe we can enable debug mode in a separate debug mode patch:
> 1. Add RFTYPE_DEBUG as a new file type. Files with this flag are for debug purpose and only be visible in\
>     debug mode.
> 2. Add RFTYPE_INVISIBLE as a new file type. Files with this flag will be invisible/not be added in resctrl fs.
> 3. Add mount parameter "debug" so that ctx->debug=true if mount -o debug is given.
> 4. If ctx->debug is true, in rdt_enable_ctx(), go through RFTYPE_DEBUG files in res_common_files[] and mark
>     fflags with RFTYPE_INVISIBLE.
> 5. In rdtgroup_add_file(), if (rft->fflags & RFTYPE_INVISIBLE) return. So the debug files will be visible only
>     in debug mode.
>
> With the debug mode patch in place, it's simple to extend to any debug files:
> In your case, update this patch by just adding RFTYPE_DEBUG in fflags. Then the debug mode will work
> for this patch automatically.
> In my case or any future debug files, we just simply add RFTYPE_DEBUG in fflags and the debug mode will
> work automatically.
>
> Does it make sense?

Yes. Sure. The debug mode needs to be resctrl mount option. I will take a
look at this further to see what can be done.

Thanks

Babu