From bramesh at vt.edu  Thu Feb 24 23:26:37 2011
From: bramesh at vt.edu (Bharath Ramesh)
Date: Fri, 25 Feb 2011 02:26:37 -0500
Subject: [ofa-general] Help with atomic operations
Message-ID: <009e01cbd4bd$56f42760$04dc7620$@edu>

Hi,
	I am trying to use IB atomic operations, specifically fetch and add.
I tried a small example but I am unable to get it to work. The WC status is
REM_INV_REQ_ERR. My sample code is as follows:

sge.addr = (uintptr_t) &data;
sge.length = sizeof (uint64_t);
sge.lkey = ib_mr->lkey;
wr.opcode = IBV_WR_ATOMIC_FETCH_AND_ADD;
wr.send_flags = IBV_SEND_SIGNALED;
wr.next = NULL;
wr.num_sge = 1;
wr.sg_list = &sge;
wr.wr.atomic.remote_addr = vaddr;
wr.wr.atomic.compare_add = 1;
//wr.wr.atomic.swap = 0;
wr.wr.atomic.rkey = rkey;
wr.wr_id = 1;
ret = ibv_post_send (ib_qp, &wr, &wr_bad);
do {
	c = ibv_poll_cq (ib_cq, 1, &wc);
} while (c == 0);

if (c < 0) {
	printf ("ERROR: ibv_poll_cq failed.\n");
      return -1;
}

if (wc.status != IBV_WC_SUCCESS) {
	// print wc info.
	// print qp status.
}

Any help on this appreciated.

Regards,

Bharath
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