Hi Tony,
On 10/11/2024 12:44 PM, Tony Luck wrote:
On Thu, Oct 10, 2024 at 03:32:08PM -0500, Moger, Babu wrote:
# 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.
Yes. There is. Each domain has its own count. I am not sure about your config.
I've been reading the code and see better now.
There are a bunch (32) of counters per domain.
But you have a system-wide allocator. So when making
a group you may allocate counters 2 and 3 for total
and local respectively. Then configure the local instance
of counter 2 on each domain (recording that in the per-domain
bitmap) for total bandwidth. Ditto for counter 3 instances
on each domain.
Yes. That is correct.
If the user updates the configuration to stop counting
on domain 1. Then the per-domain bitmap is updated to
show counters 2 and 3 are no longer in use on this domain.
But those counters aren't freed (because domain 0 is still
using them).
Yes. Correct.
Is there some hardware limitation that would prevent
re-using domain 1 counters 2 & 3 for some other group (RMID)?
Or is this just a s/w implementation detail because
you have a system wide allocator for counters?
There is no hardware limitation. It is how resctrl is designed.
In case of Intel(with two sockets, 16 CLOSIDs), You can only create 16
groups. Each group will have two domains(domain 0 for socket 0 and
domain 1 for socket 1).
# cat schemata
MB:0=100;1=100
L3:0=ffff;1=ffff;
We may have to think of addressing this sometime in the future.
--
- Babu Moger
