"mbm_assign_mode":
The supported counter assignment modes. The enclosed brackets indicate which mode
- is enabled.
+ is enabled. The MBM events associated with counters may reset when "mbm_assign_mode"
+ is changed.
::
# cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
of counters available is described in the "num_mbm_cntrs" file. Changing the
mode may cause all counters on the resource to reset.
+ Moving to mbm_event counter assignment mode requires users to assign the counters
+ to the events. Otherwise, the MBM event counters will return 'Unassigned' when read.
+
+ The mode is beneficial for AMD platforms that support more CTRL_MON
+ and MON groups than available hardware counters. By default, this
+ feature is enabled on AMD platforms with the ABMC (Assignable Bandwidth
+ Monitoring Counters) capability, ensuring counters remain assigned even
+ when the corresponding RMID is not actively used by any processor.
+
"default":
In default mode, resctrl assumes there is a hardware counter for each
result in misleading values or display "Unavailable" if no counter is assigned
to the event.
+ * To enable "mbm_event" counter assignment mode:
+ ::
+
+ # echo "mbm_event" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
+
+ * To enable "default" monitoring mode:
+ ::
+
+ # echo "default" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
+
"num_mbm_cntrs":
The maximum number of counters (total of available and assigned counters) in
each domain when the system supports mbm_event mode.
int resctrl_mbm_assign_mode_show(struct kernfs_open_file *of, struct seq_file *s, void *v);
+ssize_t resctrl_mbm_assign_mode_write(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off);
+
+void resctrl_bmec_files_show(struct rdt_resource *r, struct kernfs_node *l3_mon_kn,
+ bool show);
+
int resctrl_num_mbm_cntrs_show(struct kernfs_open_file *of, struct seq_file *s, void *v);
int resctrl_available_mbm_cntrs_show(struct kernfs_open_file *of, struct seq_file *s,
return ret ?: nbytes;
}
+/*
+ * mbm_cntr_free_all() - Clear all the counter ID configuration details in the
+ * domain @d. Called when mbm_assign_mode is changed.
+ */
+static void mbm_cntr_free_all(struct rdt_resource *r, struct rdt_mon_domain *d)
+{
+ memset(d->cntr_cfg, 0, sizeof(*d->cntr_cfg) * r->mon.num_mbm_cntrs);
+}
+
+/*
+ * resctrl_reset_rmid_all() - Reset all non-architecture states for all the
+ * supported RMIDs.
+ */
+static void resctrl_reset_rmid_all(struct rdt_resource *r, struct rdt_mon_domain *d)
+{
+ u32 idx_limit = resctrl_arch_system_num_rmid_idx();
+ enum resctrl_event_id evt;
+ int idx;
+
+ for_each_mbm_event_id(evt) {
+ if (!resctrl_is_mon_event_enabled(evt))
+ continue;
+ idx = MBM_STATE_IDX(evt);
+ memset(d->mbm_states[idx], 0, sizeof(*d->mbm_states[0]) * idx_limit);
+ }
+}
+
/*
* rdtgroup_assign_cntr() - Assign/unassign the counter ID for the event, RMID
* pair in the domain.
return 0;
}
+ssize_t resctrl_mbm_assign_mode_write(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off)
+{
+ struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
+ struct rdt_mon_domain *d;
+ int ret = 0;
+ bool enable;
+
+ /* Valid input requires a trailing newline */
+ if (nbytes == 0 || buf[nbytes - 1] != '\n')
+ return -EINVAL;
+
+ buf[nbytes - 1] = '\0';
+
+ cpus_read_lock();
+ mutex_lock(&rdtgroup_mutex);
+
+ rdt_last_cmd_clear();
+
+ if (!strcmp(buf, "default")) {
+ enable = 0;
+ } else if (!strcmp(buf, "mbm_event")) {
+ if (r->mon.mbm_cntr_assignable) {
+ enable = 1;
+ } else {
+ ret = -EINVAL;
+ rdt_last_cmd_puts("mbm_event mode is not supported\n");
+ goto out_unlock;
+ }
+ } else {
+ ret = -EINVAL;
+ rdt_last_cmd_puts("Unsupported assign mode\n");
+ goto out_unlock;
+ }
+
+ if (enable != resctrl_arch_mbm_cntr_assign_enabled(r)) {
+ ret = resctrl_arch_mbm_cntr_assign_set(r, enable);
+ if (ret)
+ goto out_unlock;
+
+ /* Update the visibility of BMEC related files */
+ resctrl_bmec_files_show(r, NULL, !enable);
+
+ /*
+ * Initialize the default memory transaction values for
+ * total and local events.
+ */
+ if (resctrl_is_mon_event_enabled(QOS_L3_MBM_TOTAL_EVENT_ID))
+ mon_event_all[QOS_L3_MBM_TOTAL_EVENT_ID].evt_cfg = r->mon.mbm_cfg_mask;
+ if (resctrl_is_mon_event_enabled(QOS_L3_MBM_LOCAL_EVENT_ID))
+ mon_event_all[QOS_L3_MBM_LOCAL_EVENT_ID].evt_cfg = r->mon.mbm_cfg_mask &
+ (READS_TO_LOCAL_MEM |
+ READS_TO_LOCAL_S_MEM |
+ NON_TEMP_WRITE_TO_LOCAL_MEM);
+ /* Enable auto assignment when switching to "mbm_event" mode */
+ if (enable)
+ r->mon.mbm_assign_on_mkdir = true;
+ /*
+ * Reset all the non-achitectural RMID state and assignable counters.
+ */
+ list_for_each_entry(d, &r->mon_domains, hdr.list) {
+ mbm_cntr_free_all(r, d);
+ resctrl_reset_rmid_all(r, d);
+ }
+ }
+
+out_unlock:
+ mutex_unlock(&rdtgroup_mutex);
+ cpus_read_unlock();
+
+ return ret ?: nbytes;
+}
+
int resctrl_num_mbm_cntrs_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
* Don't treat kernfs_find_and_get failure as an error, since this function may
* be called regardless of whether BMEC is supported or the event is enabled.
*/
-static void resctrl_bmec_files_show(struct rdt_resource *r, struct kernfs_node *l3_mon_kn,
- bool show)
+void resctrl_bmec_files_show(struct rdt_resource *r, struct kernfs_node *l3_mon_kn,
+ bool show)
{
struct kernfs_node *kn_config, *mon_kn = NULL;
char name[32];
},
{
.name = "mbm_assign_mode",
- .mode = 0444,
+ .mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = resctrl_mbm_assign_mode_show,
+ .write = resctrl_mbm_assign_mode_write,
.fflags = RFTYPE_MON_INFO | RFTYPE_RES_CACHE,
},
{
projects / thirdparty / kernel / stable.git / commitdiff
