On Jan 3, 2012, at 12:35 PM, Atchley, Scott wrote: > On Jan 3, 2012, at 11:55 AM, Hefty, Sean wrote: > >>> I have a question about a completion for a send with immediate data. The IB >>> spec (1.2.1) only mentions that the WC's immediate data be present at the >>> receiver. It is silent on the value on the sender at completion. It does say >>> that it is only valid if the WC's immediate data indicator is set. >> >> Can you provide a section reference to the spec on the areas that you're >> looking at? Looking quickly, section 11.4.2.1 reads like immediate data >> should be available in either case. >> >> I've never checked imm data on the send wc. I'm just trying to determine if >> there's an issue in the spec that should be addressed, or if this is simply >> a bug in the hca/driver. > > There is the definition in the glossary: > > Immediate Data > > Data contained in a Work Queue Element that is sent along with the payload to > the remote Channel Adapter and placed in a Receive Work Completion. > > Section 3.7.4 Transport Layer: > > The Immediate Data (IMMDT) field is optionally present in RDMA WRITE and SEND > messages. It contains data that the consumer placed in the Send or RDMA Write > request and the receiving QP will place that value in the current receive > WQE. An RDMA Write with immediate data will consume a receive WQE even though > the QP did not place any data into the receive buffer since the IMMDT is > placed in a CQE that references the receive WQE and indicates that the WQE > has completed. > > Section 11.4.1.1 Post Send Request has: > > Immediate Data Indicator. This is set if Immediate Data is to > be included in the outgoing request. Valid only for Send or > Write RDMA operations. > > 4-byte Immediate Data. Valid only for Send or Write RDMA operations. > > 11.4.2.1 Poll for Completion > > Immediate data indicator. This is set if immediate data is present. > > 4-byte immediate data. > > > None specifically mention the sender's completion event.
Sean, Any thoughts? Personally, I would like to have it in the send completion, but it might not be possible for all drivers to implement. If not, then the spec should be clarified. Scott-- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
