> > " Non-CPU agent RDT uses the RMID and CLOS tags in the same way that they are used for CPU agents."
>
> As I understand AMD uses a single specific (the highest CLOSid supported by L3)
> CLOS that is then reserved for IO allocation. While both Intel and AMD technically
> "uses CLOSid", it is done differently, no?
>
> Specifically, is this documentation introduced in patch #5 accurate for Intel?
> +             The feature routes the I/O traffic via specific CLOSID reserved
> +             for io_alloc feature. By configuring the CBM (Capacity Bit Mask)
> +             for the CLOSID, users can control the L3 portions available for
> +             I/0 traffic. The reserved CLOSID will be excluded for group creation.

No. Intel doesn't reserve a single CLOS. It allows to assign RMIDs and CLOSids
for I/O monitoring and control. Different IDs can be assigned to different groups
of devices (the "grouping" is dependent on h/w routing to devices, not
assignable by the OS).

I had some patches for this in my abandoned "resctrl2" implementation. No
immediate plans to resurrect them since it became clear that the h/w implementation
was model specific for just one generation.

-Tony

Hi Tony,

On 5/5/25 10:27 AM, Luck, Tony wrote:
>>> " Non-CPU agent RDT uses the RMID and CLOS tags in the same way that they are used for CPU agents."
>>
>> As I understand AMD uses a single specific (the highest CLOSid supported by L3)
>> CLOS that is then reserved for IO allocation. While both Intel and AMD technically
>> "uses CLOSid", it is done differently, no?
>>
>> Specifically, is this documentation introduced in patch #5 accurate for Intel?
>> +             The feature routes the I/O traffic via specific CLOSID reserved
>> +             for io_alloc feature. By configuring the CBM (Capacity Bit Mask)
>> +             for the CLOSID, users can control the L3 portions available for
>> +             I/0 traffic. The reserved CLOSID will be excluded for group creation.
> 
> No. Intel doesn't reserve a single CLOS. It allows to assign RMIDs and CLOSids
> for I/O monitoring and control. Different IDs can be assigned to different groups
> of devices (the "grouping" is dependent on h/w routing to devices, not
> assignable by the OS).

How does this work with CDP on Intel? Can CDP be enabled for CPU agents while the
"code" and "data" CLOSids be used for I/O control?

Reinette

>> No. Intel doesn't reserve a single CLOS. It allows to assign RMIDs and CLOSids
>> for I/O monitoring and control. Different IDs can be assigned to different groups
>> of devices (the "grouping" is dependent on h/w routing to devices, not
>> assignable by the OS).
>
> How does this work with CDP on Intel? Can CDP be enabled for CPU agents while the
> "code" and "data" CLOSids be used for I/O control?

Reinette,

Good question. I'll have to check with h/w folks.

-Tony