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

[Steve Wise]

> > By the way, in case its not clear:  The SEND/RECV exchanges are done
> > just to advertise source and sink memory regions, and to indicate
> > completion of rdma read and write operations to the peer.  The
> > "ping/pong" data is transferred with rdma read and write operations.
> > 
> > Thanks for the feedback!
> > 
> 
> Code tends to get copied around ... its easy to imagine someone
> copying this and measuring the send latency. Just posting many WRs
> in the initialization sequence, with no other code changes,
> will fix this problem.
> 

Each "ping/pong" iteration with rping is composed of 2 sends on the
client side, 2 sends on the server side, plus 1 rdma read and 1 rdma
write on the server side.  

Again, latency performance (or any performance) isn't a goal of this
program.  Testing CMA, CQ and CMA event notifications, and
send/recv/rr/rw are the goals.
 

snipit from the patch:

+/*
+ * rping "ping/pong" loop:
+ *     client sends source rkey/addr/len
+ *     server receives source rkey/add/len
+ *     server rdma reads "ping" data from source
+ *     server sends "go ahead" on rdma read completion
+ *     client sends sink rkey/addr/len
+ *     server receives sink rkey/addr/len
+ *     server rdma writes "pong" data to sink
+ *     server sends "go ahead" on rdma write completion
+ *     <repeat loop>
+ */


Can you be more specific on what you think I should change?  Are you
suggesting I post more RECVs?   

Steve.