[ofa-general] QoS RFC

[Or Gerlitz]

Yevgeny Kliteynik wrote:

> Please find the attached RFC describing how QoS policy support could be 
> implemented in the OpenFabrics stack.
> Your comments are welcome.

Hi Yevgeny,

Some quick comments from first re-read

1) IPoIB - just to make sure I am on the right page:

the intention is that the QoS params would be per --partition-- and 
hence the IPv4 broadcast multicast group sl, rate etc params would be 
used for each address handle created by this IPoIB device

2) RDMA CM (CMA) based ULPs -

Assuming the rdma cm api would be enhanced for the consumer to 
optionally provide the "qos class", why have a dedicated section at the 
doc for iSER? there are bunch of other rdma cm based ULPs (eg 
Lustre/rNFS/RDS/etc/etc) which would be able to get QoS through the IB 
sys admin configuration of QoS policy at the SM/SA

3) RC based ULPs - I was thinking that the SL should be derived from the 
sid AND the pkey, I wonder if the IBTA related annex addresses this.

4) at some cases, the SID to be used is not known in advance: 
specifically the somehow canonical example is MPI implementations that 
request for the CM to allocate SID per rank per job, which means that 
you want huge dynamic bunch of SIDs to be mapped by the SA to the same SL.

At the past my thinking to handle this was to change the CM such that 
users can ask for a --SID in a range-- and have this range be mapped to 
a specific SID in the SM/SA (same here maybe the IBTA annex says 
something re that)

Or.