[openib-general] question on QoS support

[Oliver]

Hi, folks -

I am trying to verify and evaluate IB QoS support, running openSM as
subnet manager. The perftest program is extended to set SL as command
line options instead of default 0, and by modifying VL arbitration
tables, I am expecting to see the traffic shaping can actually take
place, but it did not.  More details on configuration:

in opensm.opts:
# QoS default options
qos_high_limit 255 # disable low priority table
qos_vlarb_high: 0:4,1:4,2:8,3:0, 4:0 .... # this is to give VL 2
(corresponding to SL 2) a higher weight 8
qos_sl2vl 0,1,2,3,4, ... # no changes here

I think (though not verified) the Voltaire HCA we are using can
support 8 data VLs. I don't have much more information to go on why
qos shaping is not taking place, any suggestions?

A related question is, if I modify qos setting in SM, do I need to
restart SA on each hosts for it to see the changes? (I am hoping not,
as I tried in the test, it doesn't seem to make a difference)

Thanks for help.
-- 
Oliver