On Tue, Jul 12, 2022 at 07:55:21PM +0000, Ajay Sharma wrote: > Hello, > > We have a situation where the hardware treats cq creation differently > when attaching it to RAW_QP use case vs the RC_QP use case. The > situation is as follows : > > > When creating the cq for RAW_QP_TYPE use case , the hw requires that > memory be registered with the hw but it does not yet attaches it to the > qp meaning it does not yet allocate any hw side resources for the cq. > > The hardware will allocate resources for this qp type only when it > see’s the work queue creation request and that’s when it allocates > resources for both cq and wq. > > > When creating cq for the RC_QP_TYPE use case the hardware creates > resources immediately on cq creation request. > > > The problem is from the user mode side there is no way to tell whether > this cq is intended for RAW QP use case or RC QP use case. Can we add a > flag in the ibv_cq_init_attr_ex to differentiate the use case we are > trying to address. > > We have explored the option of customizing in the firmware side and at > this point it seems a very expensive operation and would like to avoid > that. I don't have a good advice for you, this is very non-compliant if CQs can only be used in certain configurations. The entire verbs is designed around the idea that the CQ is a sharable object - having a device that creates a CQ for every queue is very far away. Why can you not correct this? A flag is not so sufficient, it is an entire set of bad behavior that you have to opt into. You may consider a dv for creating a QP/CQ pair if that models your HW. Jason
