RE: [PATCH v8 08/25] x86/resctrl: Introduce interface to display number of monitoring counters

[Luck, Tony]

> > Why have this complexity in mbm_assign_control syntax?
>
> Lets take an example:
> $ cat /sys/fs/resctrl/info/L3_MON/num_mbm_cntrs
> Total 32
> Available 30
>
> # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
> //0=tl;1=tl;
>
> Here default group has taken two counters.
>
> # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
> //0=_;1=tl;
>
> Here default group has two counters.
> Domain 0 does not have counters applied. So, you wont be able to read the
> MBM values for domain 0.
> Domain 1 has both the counters applied.

Is there some benefit from doing this? You are still using the same
number of counters. You now can't read them from domain 0.

You said the counters are system-wide. Does that mean that in 
this case:

# cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
//0=tl;1=tl;

there aren't separate counts from each of domain 0 and domain 1.
I.e. if I read both I'd see the same value (sum of traffic on both domains):

$ grep . /sys/fs/resctrl/mon_data/*/*total*
/sys/fs/resctrl /mon_data/mon_L3_00/mbm_total_bytes:260039467008
/sys/fs/resctrl /mon_data/mon_L3_01/mbm_total_bytes:260039467008

-Tony