[openib-general] How heavy to resize a CQ ?

[Roland Dreier]

 > 	 In dynamic process application, we don't know how many
 > connections a process will make when we create the CQ, so we don't know
 > the CQ size, what we do is to increase the CQ size when a new connection
 > is made, and decrease the CQ size when a connection is destroyed. My
 > question is, is ibv_resize_cq() a lightweight function call ?  Do we
 > have to drain the CQ before we resize the CQ ?

I would say that resizing a CQ is not lightweight -- I've never
benchmarked it but it's probably comparable to creating a CQ or
something like that.  There is no requirement to drain the CQ or
anything like that before resizing it -- you can resize it any time,
even if it is currently getting completions or being polled.

 - R.