From mboxrd@z Thu Jan  1 00:00:00 1970
From: floaterions <floaterions-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: RDMA atomic operations fail
Date: Wed, 24 Dec 2014 03:08:45 +0000 (UTC)
Message-ID: <loom.20141224T040342-951@post.gmane.org>
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When I try to submit an RDMA FETCH_AND_ADD or CMP_AND_SWAP ,
the ibv_post_send() function fails, with Errno set to "Invalid argument".
I have no such problems with RDMA READ/WRITE. 

I developed my entire code using RDMA CM (so no manual QP transitioning). 
The queue pair is RC, and Atomic is enabled at the responder queue pair,
and the memory regions are registered with atomic access.

I suspected that there might be the source of this problem,
so I wrote a small program using libibcm where I transition the QPs manually
and set the flags fro atomic operations:
qp_attr->qp_access_flags = IBV_ACCESS_REMOTE_ATOMIC; 
qp_attr->max_rd_atomic = <something greater than zero>; 
qp_attr->max_dest_rd_atomic = <something greater than zero>; 

But still, the same error (invalid argument).

I'd appreciate your help.

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