Hi Reinette, On 7/17/25 22:53, Reinette Chatre wrote: > Hi Babu, > > On 7/8/25 3:17 PM, Babu Moger wrote: >> When the "mbm_event" counter assignment mode is enabled, a hardware counter >> must be assigned to read the event. >> >> Report 'Unassigned' in case the user attempts to read the event without >> assigning a hardware counter. >> >> Signed-off-by: Babu Moger <babu.moger@xxxxxxx> >> --- > > > >> --- >> Documentation/filesystems/resctrl.rst | 8 ++++++++ >> fs/resctrl/ctrlmondata.c | 6 ++++++ >> 2 files changed, 14 insertions(+) >> >> diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst >> index 446736dbd97f..4f5eb5bbd4b5 100644 >> --- a/Documentation/filesystems/resctrl.rst >> +++ b/Documentation/filesystems/resctrl.rst >> @@ -434,6 +434,14 @@ When monitoring is enabled all MON groups will also contain: >> for the L3 cache they occupy). These are named "mon_sub_L3_YY" >> where "YY" is the node number. >> >> + The "mbm_event" counter assignment mode offers "num_mbm_cntrs" number of >> + counters and allows users to assign counters to mon_hw_id, event pairs >> + enabling bandwidth monitoring for as long as the counter remains assigned. >> + The hardware will continue tracking the assigned counter until the user >> + manually unassigns it, ensuring that event data is not reset during this >> + period. An MBM event returns 'Unassigned' when the event does not have >> + a hardware counter assigned. > > Most of this duplicates the "mbm_event" description added in patch #10. It should just > be sufficient to mention that this applies to "mbm_event" counter assignment mode > and then user can look up the main description in the doc. > > The last sentence is related to this section and need an update to reflect behavior > when a CTRL_MON event is read and it or some of the MON groups do not have > counters assigned. The paragraph that precedes this does describe how the sum > works so this can tie into that. Just added following text. When the 'mbm_event' counter assignment mode is enabled, reading an MBM event returns 'Unassigned' if no hardware counter is assigned to it. For CTRL_MON groups, 'Unassigned' is returned if none of the events in the CTRL_MON group or its associated MON groups have assigned counters. > >> + >> "mon_hw_id": >> Available only with debug option. The identifier used by hardware >> for the monitor group. On x86 this is the RMID. >> diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c >> index ce766b2cdfc1..45351673e4ee 100644 >> --- a/fs/resctrl/ctrlmondata.c >> +++ b/fs/resctrl/ctrlmondata.c >> @@ -661,10 +661,16 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) >> >> checkresult: >> >> + /* >> + * -ENOENT is a special case, set only when "mbm_event" counter assignment >> + * mode is enabled and no counter has been assigned. >> + */ >> if (rr.err == -EIO) >> seq_puts(m, "Error\n"); >> else if (rr.err == -EINVAL) >> seq_puts(m, "Unavailable\n"); >> + else if (rr.err == -ENOENT) >> + seq_puts(m, "Unassigned\n"); >> else >> seq_printf(m, "%llu\n", rr.val); >> > > As mentioned in previous patch, please squash with previous patch. > Sure. -- Thanks Babu Moger
