On 2/20/2024 12:11 PM, Peter Newman wrote:
Hi James,
On Tue, Feb 20, 2024 at 7:21 AM James Morse <james.morse@xxxxxxx> wrote:
On 16/02/2024 20:18, Peter Newman wrote:
On Thu, Feb 8, 2024 at 9:29 AM Moger, Babu <babu.moger@xxxxxxx> wrote:
On 2/5/24 16:38, Reinette Chatre wrote:
You have made it clear on several occasions that you do not intend to support
domain level assignment. That may be ok but the interface you create should
not prevent future support of domain level assignment.
If my point is not clear, could you please share how this interface is able to
support domain level assignment in the future?
I am starting to think that we need a file similar to the schemata file
for group and domain level monitor configurations.
Something like this?
By default
#cat /sys/fs/resctrl/monitor_state
default:0=total=assign,local=assign;1=total=assign,local=assign
With ABMC,
#cat /sys/fs/resctrl/monitor_state
ABMC:0=total=unassign,local=unassign;1=total=unassign,local=unassign
The benefit from all the string parsing in this interface is only
halving the number of monitor_state sysfs writes we'd need compared to
creating a separate file for mbm_local and mbm_total. Given that our
use case is to assign the 32 assignable counters to read the bandwidth
of ~256 monitoring groups, this isn't a substantial gain to help us. I
think you should just focus on providing the necessary control
granularity without trying to consolidate writes in this interface. I
will propose an additional interface below to optimize our use case.
Whether mbm_total and mbm_local are combined in the group directories
or not, I don't see why you wouldn't just repeat the same file
interface in the domain directories for a user needing finer-grained
controls.
I don't follow why this has to be done globally. resctrl allows CLOSID to have different
configurations for different purposes between different domains (as long as tasks are
pinned to CPUs). It feels a bit odd that these counters can't be considered as per-domain too.
Assigning to all domains at once would allow us to better parallelize
the resulting IPIs when we do need to iterate a small set of monitors
over a large list of groups.
Planning to work on v3 of this series. For now, I will exclude the
global assignment option from this series.
We can add the global assignment support when we get time to optimize
assignments at later point.
Thanks
Babu Moger
