Hi Babu,
On 7/8/25 3:17 PM, Babu Moger wrote:
> Enable the mbm_l3_assignments resctrl file to be used to modify counter
> assignments of CTRL_MON and MON groups when the "mbm_event" counter
> assignment mode is enabled.
>
> The assignment modifications are done in the following format:
> <Event>:<Domain id>=<Assignment state>
>
> Event: A valid MBM event in the
> /sys/fs/resctrl/info/L3_MON/event_configs directory.
>
> Domain ID: A valid domain ID. When writing, '*' applies the changes
> to all domains.
>
> Assignment states:
>
> _ : Unassign the counter.
"the counter" -> "a counter" (user cannot control which counter is assigned)
>
> e : Assign the counter exclusively.
"the counter" -> "a counter"
>
> Examples:
>
> $ cd /sys/fs/resctrl
> $ cat /sys/fs/resctrl/mbm_L3_assignments
> mbm_total_bytes:0=e;1=e
> mbm_local_bytes:0=e;1=e
>
> To unassign the counter associated with the mbm_total_bytes event on
> domain 0:
>
> $ echo "mbm_total_bytes:0=_" > mbm_L3_assignments
> $ cat /sys/fs/resctrl/mbm_L3_assignments
> mbm_total_bytes:0=_;1=e
> mbm_local_bytes:0=e;1=e
>
> To unassign the counter associated with the mbm_total_bytes event on
> all the domains:
>
> $ echo "mbm_total_bytes:*=_" > mbm_L3_assignments
> $ cat /sys/fs/resctrl/mbm_L3_assignments
> mbm_total_bytes:0=_;1=_
> mbm_local_bytes:0=e;1=e
>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
...
> ---
> Documentation/filesystems/resctrl.rst | 146 +++++++++++++++++++++++++-
> fs/resctrl/internal.h | 2 +
> fs/resctrl/monitor.c | 18 ++++
> fs/resctrl/rdtgroup.c | 123 +++++++++++++++++++++-
> 4 files changed, 287 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
> index 4dd1d605d6ad..2b2acb55d8b1 100644
> --- a/Documentation/filesystems/resctrl.rst
> +++ b/Documentation/filesystems/resctrl.rst
> @@ -527,7 +527,8 @@ When the "mba_MBps" mount option is used all CTRL_MON groups will also contain:
> Event: A valid MBM event in the
> /sys/fs/resctrl/info/L3_MON/event_configs directory.
>
> - Domain ID: A valid domain ID.
> + Domain ID: A valid domain ID. When writing, '*' applies the changes
> + to all the domains.
>
> Assignment states:
>
> @@ -544,6 +545,34 @@ When the "mba_MBps" mount option is used all CTRL_MON groups will also contain:
> mbm_total_bytes:0=e;1=e
> mbm_local_bytes:0=e;1=e
>
> + Assignments can be modified by writing to the interface.
> +
> + Example:
> + To unassign the counter associated with the mbm_total_bytes event on domain 0:
> + ::
> +
> + # echo "mbm_total_bytes:0=_" > /sys/fs/resctrl/mbm_L3_assignments
> + # cat /sys/fs/resctrl/mbm_L3_assignments
> + mbm_total_bytes:0=_;1=e
> + mbm_local_bytes:0=e;1=e
> +
> + To unassign the counter associated with the mbm_total_bytes event on all the domains:
> + ::
> +
> + # echo "mbm_total_bytes:*=_" > /sys/fs/resctrl/mbm_L3_assignments
> + # cat /sys/fs/resctrl/mbm_L3_assignments
> + mbm_total_bytes:0=_;1=_
> + mbm_local_bytes:0=e;1=e
> +
> + To assign the counter associated with the mbm_total_bytes event on all domains in
"the counter" -> "a counter" (motivation: user space cannot control which counter is assigned)
> + exclusive mode:
> + ::
> +
> + # echo "mbm_total_bytes:*=e" > /sys/fs/resctrl/mbm_L3_assignments
> + # cat /sys/fs/resctrl/mbm_L3_assignments
> + mbm_total_bytes:0=e;1=e
> + mbm_local_bytes:0=e;1=e
> +
> Resource allocation rules
> -------------------------
>
> @@ -1579,6 +1608,121 @@ View the llc occupancy snapshot::
> # cat /sys/fs/resctrl/p1/mon_data/mon_L3_00/llc_occupancy
> 11234000
>
> +
> +Examples on working with mbm_assign_mode
> +========================================
> +
> +a. Check if MBM counter assignment mode is supported.
> +::
> +
> + #mount -t resctrl resctrl /sys/fs/resctrl/
"#mount" -> "# mount" (please build htmldocs to confirm everything
looks consistent)
> +
> + # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
> + [mbm_event]
> + default
> +
> +The "mbm_event" mode is detected and enabled.
> +
> +b. Check how many assignable counters are supported.
> +::
> +
> + # cat /sys/fs/resctrl/info/L3_MON/num_mbm_cntrs
> + 0=32;1=32
> +
> +c. Check how many assignable counters are available for assignment in each domain.
> +::
> +
> + # cat /sys/fs/resctrl/info/L3_MON/available_mbm_cntrs
> + 0=30;1=30
> +
> +d. To list the default group's assign states:
Please note that these steps are inconsistent. Some end with "." and some end with ":"
> +::
> +
> + # cat /sys/fs/resctrl/mbm_L3_assignments
> + mbm_total_bytes:0=e;1=e
> + mbm_local_bytes:0=e;1=e
> +
> +e. To unassign the counter associated with the mbm_total_bytes event on domain 0:
> +::
> +
> + # echo "mbm_total_bytes:0=_" > /sys/fs/resctrl/mbm_L3_assignments
> + # cat /sys/fs/resctrl/mbm_L3_assignments
> + mbm_total_bytes:0=_;1=e
> + mbm_local_bytes:0=e;1=e
> +
> +f. To unassign the counter associated with the mbm_total_bytes event on all domains:
> +::
> +
> + # echo "mbm_total_bytes:*=_" > /sys/fs/resctrl/mbm_L3_assignments
> + # cat /sys/fs/resctrl/mbm_L3_assignment
> + mbm_total_bytes:0=_;1=_
> + mbm_local_bytes:0=e;1=e
> +
> +g. To assign a counter associated with the mbm_total_bytes event on all domains in
ah ... here "a counter" is used.
> +exclusive mode:
> +::
> +
> + # echo "mbm_total_bytes:*=e" > /sys/fs/resctrl/mbm_L3_assignments
> + # cat /sys/fs/resctrl/mbm_L3_assignments
> + mbm_total_bytes:0=e;1=e
> + mbm_local_bytes:0=e;1=e
> +
> +h. Read the events mbm_total_bytes and mbm_local_bytes of the default group. There is
> +no change in reading the events with the assignment. If the event is unassigned when
> +reading, then the read will come back as "Unassigned".
Since returning "Unassigned" can be complicated, the associated description should
probably just be done once in the doc. I expect this will be in the "mon_data" section.
> +::
> +
> + # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_total_bytes
> + 779247936
> + # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes
> + 765207488
> +
> +i. Check the default event configurations.
Drop "default" (there are only these event configurations)
> +::
> +
> + # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_total_bytes/event_filter
> + local_reads,remote_reads,local_non_temporal_writes,remote_non_temporal_writes,
> + local_reads_slow_memory,remote_reads_slow_memory,dirty_victim_writes_all
> +
> + # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_local_bytes/event_filter
> + local_reads,local_non_temporal_writes,local_reads_slow_memory
> +
> +j. Change the event configuration for mbm_local_bytes.
> +::
> +
> + # echo "local_reads, local_non_temporal_writes, local_reads_slow_memory, remote_reads" >
> + /sys/fs/resctrl/info/L3_MON/counter_configs/mbm_local_bytes/event_filter
"counter_configs" -> "event_configs" (this was also an issue in previous series, please
use grep to ensure all are fixed)
> +
> + # cat /sys/fs/resctrl/info/L3_MON/counter_configs/mbm_local_bytes/event_filter
"counter_configs" -> "event_configs"
> + local_reads,local_non_temporal_writes,local_reads_slow_memory,remote_reads
> +
> +This will update all (across all domains of all monitor groups) counter assignments
> +associated with the mbm_local_bytes event.
> +
> +k. Now read the local event again. The first read may come back with "Unavailable"
> +status. The subsequent read of mbm_local_bytes will display the current value.
> +::
> +
> + # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes
> + Unavailable
> + # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes
> + 314101
> +
> +l. Users have the option to go back to 'default' mbm_assign_mode if required. This can be
> +done using the following command. Note that switching the mbm_assign_mode may reset all
> +the MBM counters (and thus all MBM events) of all the resctrl groups.
> +::
> +
> + # echo "default" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
> + # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
> + mbm_event
> + [default]
> +
> +m. Unmount the resctrl
"Unmount the resctrl" -> "Unmount resctrl" or "Unmount the resctrl filesystem"?
> +::
> +
> + #umount /sys/fs/resctrl/
"#umount" -> "# umount"
> +
> Intel RDT Errata
> ================
>
> diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
> index b42890fd937a..9881674909f2 100644
> --- a/fs/resctrl/internal.h
> +++ b/fs/resctrl/internal.h
> @@ -403,6 +403,8 @@ bool closid_allocated(unsigned int closid);
>
> int resctrl_find_cleanest_closid(void);
>
> +struct mon_evt *mbm_get_mon_event_by_name(struct rdt_resource *r, char *name);
> +
> int rdtgroup_assign_cntr_event(struct rdt_mon_domain *d, struct rdtgroup *rdtgrp,
> struct mon_evt *mevt);
> void rdtgroup_unassign_cntr_event(struct rdt_mon_domain *d, struct rdtgroup *rdtgrp,
> diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
> index e30a867c00bb..61419849b257 100644
> --- a/fs/resctrl/monitor.c
> +++ b/fs/resctrl/monitor.c
> @@ -1220,3 +1220,21 @@ void resctrl_update_cntr_allrdtgrp(struct mon_evt *mevt)
> rdtgroup_update_cntr_event(r, crgrp, mevt->evtid);
> }
> }
> +
> +/*
> + * mbm_get_mon_event_by_name() - Return the mon_evt entry for the matching
> + * event name.
> + */
> +struct mon_evt *mbm_get_mon_event_by_name(struct rdt_resource *r, char *name)
> +{
> + struct mon_evt *mevt;
> +
> + for_each_mon_event(mevt) {
> + if (mevt->rid == r->rid && mevt->enabled &&
> + resctrl_is_mbm_event(mevt->evtid) &&
> + !strcmp(mevt->name, name))
> + return mevt;
> + }
> +
> + return NULL;
> +}
> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
> index dc108c5db298..b26baca389bb 100644
> --- a/fs/resctrl/rdtgroup.c
> +++ b/fs/resctrl/rdtgroup.c
> @@ -2071,6 +2071,126 @@ static int mbm_L3_assignments_show(struct kernfs_open_file *of, struct seq_file
> return ret;
> }
>
> +static int rdtgroup_modify_assign_state(char *assign, struct rdt_mon_domain *d,
Please move to monitor.c
> + struct rdtgroup *rdtgrp, struct mon_evt *mevt)
> +{
> + int ret = 0;
> +
> + if (!assign || strlen(assign) != 1)
> + return -EINVAL;
> +
> + switch (*assign) {
> + case 'e':
> + ret = rdtgroup_assign_cntr_event(d, rdtgrp, mevt);
This patch enables the user to assign counters to multiple events in a
single write. Looking at this flow:
rdtgroup_assign_cntr_event()->rdtgroup_alloc_config_cntr() may thus
be called on the same domain but for different events in a single write from
user space.
I thus think that the error message in rdtgroup_alloc_config_cntr()
should not just contain the domain ID, but also the event *name*
(not the ID since user space cannot be expect to understand if).
considering this it seems that @mevt can be passed through
to rdtgroup_alloc_config_cntr() instead of just the event ID to support
this?
> + break;
> + case '_':
> + rdtgroup_unassign_cntr_event(d, rdtgrp, mevt);
> + break;
> + default:
> + ret = -EINVAL;
Please add a "break".
> + }
> +
> + return ret;
> +}
> +
> +static int resctrl_process_assign(struct rdt_resource *r, struct rdtgroup *rdtgrp,
Please move to monitor.c and rename to be more specific. For example,
resctrl_parse_mbm_assignment()? Open to ideas.
> + char *event, char *tok)
> +{
> + struct rdt_mon_domain *d;
> + unsigned long dom_id = 0;
> + char *dom_str, *id_str;
> + struct mon_evt *mevt;
> + int ret;
> +
> + mevt = mbm_get_mon_event_by_name(r, event);
> + if (!mevt) {
> + rdt_last_cmd_printf("Invalid event %s\n", event);
> + return -ENOENT;
> + }
> +
> +next:
> + if (!tok || tok[0] == '\0')
> + return 0;
> +
> + /* Start processing the strings for each domain */
> + dom_str = strim(strsep(&tok, ";"));
> +
> + id_str = strsep(&dom_str, "=");
> +
> + /* Check for domain id '*' which means all domains */
> + if (id_str && *id_str == '*') {
> + ret = rdtgroup_modify_assign_state(dom_str, NULL, rdtgrp, mevt);
> + if (ret)
> + rdt_last_cmd_printf("Assign operation '%s:*=%s' failed\n",
> + event, dom_str);
> + return ret;
> + } else if (!id_str || kstrtoul(id_str, 10, &dom_id)) {
> + rdt_last_cmd_puts("Missing domain id\n");
> + return -EINVAL;
> + }
> +
> + /* Verify if the dom_id is valid */
> + list_for_each_entry(d, &r->mon_domains, hdr.list) {
> + if (d->hdr.id == dom_id) {
> + ret = rdtgroup_modify_assign_state(dom_str, d, rdtgrp, mevt);
> + if (ret) {
> + rdt_last_cmd_printf("Assign operation '%s:%ld=%s' failed\n",
> + event, dom_id, dom_str);
> + return ret;
> + }
> + goto next;
> + }
> + }
> +
> + rdt_last_cmd_printf("Invalid domain id %ld\n", dom_id);
> + return -EINVAL;
> +}
> +
Reinette
