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

[Moger, Babu]

Hi Tony,

On 10/10/24 12:08, Luck, Tony wrote:
> Babu,
> 
>> We have the information already in r->mon.mbm_cntr_free_map.
>>
>> How about adding an extra text while printing num_mbm_cntrs?
>>
>> $ cat /sys/fs/resctrl/info/L3_MON/num_mbm_cntrs
>>   Total 32, Available 16
> 
> Either that or:
> Total 32
> Available 16
> 

Sure. Fine with me.

> which looks fractionally simpler to parse. But I don't have strong feelings.
> 
>> There are all global counters, we don't differentiate between sockets just
>> like number of CLOSIDs.
> 
> Interesting. So there is no real benefit from "0=tl;1=_" ... you are using
> up two counters, just not reporting them on socket 1.
> 
> 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.

Domain level application is important.

This is similar to what we have with schemata. You can change the value in
each individual domain.
#cat schemata
    MB:0=2048;1=2048;2=2048;3=2048
    L3:0=ffff;1=ffff;2=ffff;3=ffff


> 
> You could have just {grouppath}/{allocation}
> 
> where allocation is one of _, t, l, tl
> 
> -Tony

-- 
Thanks
Babu Moger