On Tue, Dec 04, 2018 at 04:38:52PM +0200, Gal Pressman wrote: > On 04-Dec-18 14:44, Leon Romanovsky wrote: > > On Tue, Dec 04, 2018 at 02:04:17PM +0200, Gal Pressman wrote: > >> Add EFA node type, transport type and protocol type to core code. > >> EFA relies on underlying implementation similar to reliable datagram, so > >> we also define a new QP type named Scalable Reliable Datagram (SRD). > >> > >> EFA reliable datagram transport provides reliable out-of-order delivery, > >> transparently utilizing multiple network paths to reduce network tail > >> latency. Its interface is similar to UD, in particular it supports > >> message size up to MTU, with error handling extended to support reliable > >> communication. > >> > >> Signed-off-by: Gal Pressman <galpress@xxxxxxxxxx> > >> --- > >> drivers/infiniband/core/verbs.c | 2 ++ > >> include/rdma/ib_verbs.h | 9 +++++++-- > >> 2 files changed, 9 insertions(+), 2 deletions(-) > >> > > > > Do you have any specification/documentation for that? > > > > I'm afraid that awesome press release [1] is not enough. > > > > [1] > > https://aws.amazon.com/about-aws/whats-new/2018/11/introducing-elastic-fabric-adapter/ > > > > Thanks > > > > Hey Leon, > The commit message (and part of the cover letter) contains a description of SRD. > It is similar to UD in most ways with the addition of reliable out-of-order > delivery. The work requests usage are the same as UD with a minor difference in > the completion's status codes. > > The exact specification is internal to AWS, but if you have any more questions > I'll be more than happy to answer. All structures which you extended are backed by IBTA and everything that "internal to .." is supposed to be implemented by various extensions which we already have in RDMA/core. For example, in case of SRD, we have IB_QPT_DRIVER exactly for that. Otherwise, please provide full semantics of this SRD type: out-of-order semantics, handle of errors, state diagram, retransmission e.t.c. Thanks
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