Philip Frey1 wrote:
Steve, thanks for your advice.
Is it possible that there is a bug in OFED 1.3 with regard to
non-signaled send work requests?
I noticed that when I post send work requests onto my send queue, It
eventually fills up until I
cannot post sends anymore.
This happens with the Chelsio T3 RNIC and OFED 1.3 whenever I post
send WR's that have
their flags set to 0. It does not happen though when I post sends with
IBV_SEND_SIGNALED.
The CQ is empty in the case of non-signaled WR's (as expected) but
they somehow seem to
be stuck on the send queue.
I use the following code:
static struct ibv_send_wr tx_wr, *bad_wr;
/* create send work request */
tx_wr.wr_id = tx_wr_id++;
tx_wr.next = NULL;
tx_wr.sg_list = sg_list;
tx_wr.num_sge = num_sge;
tx_wr.opcode = IBV_WR_SEND;
tx_wr.send_flags = 0;
/* post send work request */
ret = ibv_post_send(qp, &tx_wr, &bad_wr);
if (ret) {
//error
}
I learned that it might be necessary to post a signaled send WR after
posting a number of non-signaled
ones in order to clean up the SQ. Is that the case and is there no way
to post non-signaled WR's that
do not get stuck on the SQ?
That is the case.
You must post at least one signaled WR every SQ-depth's worth of posts
to force the SQ to be cleaned up. From the driver's perspective, it
cannot tell whether an unsignaled WR completed successfully until a
subsequent signaled work request completes. This boils down to a
requirement that you post at least one signaled WR before filling up the SQ.
Steve.
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