Thanks for all your replies. So my general question is, why only 4bytes immediate data can Generate completion event on B side, Why RDMA-write with any data size does not generate A completion event on B side? basic there are the same thing, the only different is, one Copy 4bytes to completion structure, the other copy all data to provided dest buffer.
--CQ >-----Original Message----- >From: Ralph Campbell [mailto:[EMAIL PROTECTED] >Sent: Wednesday, August 23, 2006 1:16 PM >To: Tang, Changqing >Cc: Caitlin Bestler; openib-general@openib.org >Subject: RE: [openib-general] basic IB doubt > >On Wed, 2006-08-23 at 12:28 -0500, Tang, Changqing wrote: >> > >> >Actually, A knows the data is in B's memory when A gets the >> >completion notice. B can't rely on anything unless A uses the RDMA our >> >write with immediate which puts a completion event in B's CQ. >> >> Ralph: >> >> Can you give a few more words on 'immediate', I know A will have A >> completion event in its CQ, Does B receive a CQ event on the >Same RDMA >> operation as well ? >> >> --CQ Tang > >B doesn't get a completion event for a RDMA write initiated >from A unless A does something like the following: > > struct ib_send_wr wr; > > wr.opcode = IB_WR_RDMA_WRITE_WITH_IMM; > wr.imm_data = cpu_to_be32(value); > ... > ib_post_send(qp, &wr, NULL); > >B will get a completion event with the IB_WC_WITH_IMM flag set >in struct ib_wc.wc_flags and ib_wc.imm_data set to the value >that A sent. > > _______________________________________________ openib-general mailing list openib-general@openib.org http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general