UCP: API - adding priority attribute to ucp requests

[roiedanino]

What

Adding priority attribute to ucp_request_param_t

Why ?

Upcoming feature - high-priority messages, on supporting transports.

[shamisp]

Few questions:

1. What is the use case and how it is going to be implemented ?
2. I don't thinking just stating "the priorities" is sufficient for QoS definition.E.g. Is this high priority for BW or latency ? Whaat "high" actually means. Do we optimize for minimum service level or max service levels ?

The above API definition is not complete. It requires more clarity and definition what you trying to achieve. Demonstration of working implementation also will be necessary for this change.

[roiedanino]

what is the use case and how it is going to be implemented ? I don't thinking just stating "the priorities" is sufficient for QoS definition.

Use Case

Prioritizing specific messages when possible, UCX will rely on HW configuration, for example: HW will be configured with a high-priority SL and UCX will be configured accordingly: UCX_IB_HIGH_PRIORITY_SL=<hw configured sl>

Implementation:

1. Some of the ifaces will have priority messages capability
2. Each uct_ep created at UCP level will have a matching high-priority uct_ep if iface is capable
3. For each request: request_param_t will indicate the priority level: in case the selected lane / the ep supports prioritizing, the priority uct_ep will be used, in ib that ep will be configured to use the UCX_IB_HIGH_PRIORITY_SL value as sl.

[shamisp]

what is the use case and how it is going to be implemented ? I don't thinking just stating "the priorities" is sufficient for QoS definition.

Use Case

Prioritizing specific messages when possible, UCX will rely on HW configuration, for example: HW will be configured with a high-priority SL and UCX will be configured accordingly: UCX_IB_HIGH_PRIORITY_SL=

Implementation:

1. Some of the ifaces will have priority messages capability
2. Each uct_ep created at UCP level will have a matching high-priority uct_ep if iface is capable
3. For each request: request_param_t will indicate the priority level: in case the selected lane / the ep supports prioritizing, the priority uct_ep will be used, in ib that ep will be configured to use the UCX_IB_HIGH_PRIORITY_SL value as sl.

Can you please specify application use case ?

[yosefe]

@shamisp can you pls take a look?

[gleon99]

@shamisp can look please?