[openib-general] Re: [PATCH] [RFC] - example user mode rdma ping/pongprogram using CMA

[Michael S. Tsirkin]

Quoting r. Steve Wise <swise at opengridcomputing.com>:
> Subject: [PATCH] [RFC] - example user mode rdma ping/pongprogram using CMA
> 
> All,
> 
> Attached is a user-mode program, called rping, that uses librdmacm and
> libibverbs to implement a ping-pong program over an RC connection.  The
> program utilizes SEND, RECV, RDMA READ, and WRITE ops, as well as cq
> channels to get cq events, and rdma_get_event() to detect CMA events.
> It is multi-threaded.  
> 
> I've built it as an example program in librdmacm/examples and tested it
> with mthca.  It is useful to test CMA as well as all the major rdma
> operations in a transport-neutral way.
> 
> If you all find it has utility, please pull it into librdmacm/examples.
> 
> 
> Signed-off-by: Steve Wise <swise at opengridcomputing.com>

Steve, looks like you have at most a single receive work request posted at the
receive workqueue at all times.
If true, this is *really* not a good idea, performance-wise, even if you
actually have at most 1 packet in flight.


-- 
Michael S. Tsirkin
Staff Engineer, Mellanox Technologies