Hi, thanks to all for adding information.
In continuation, If i am transferring only a single byte using RDMA write, then can i poll on this byte arrival on receiving side ? Atleast, can one be sure in single byte case ? Thanks and Regards, Yogeshwar 2010/2/10 Håkon Bugge <[email protected]>: > > On Feb 9, 2010, at 19:08 , अनुज wrote: > > On Tue, Feb 2, 2010 at 9:35 PM, Håkon Bugge <[email protected]> wrote: >> >> [snip] >> Now, most MPI implementation does not obey this; IIRC MVAPICH does rely on >> the last byte (word?) being written after all other payload, > > But MVAPICH assumes last byte is written in last. What if that is not the > case? > > I would assume you in that case copy incorrect data from your IB receive > buffer to your application receive buffer (assuming a one-copy receive). > This can happen with a less conservative IB implementation and/or weak > ordering of I/O transactions. > > >> >> Scali MPI relies on 4-byte write atomicy and uses a special >> encoding/decoding which sustains any reordering of the payload (as long as >> each 4-byte word is written as an atomic unit). The benefit, besides >> robustness, is the capability of a worm-hole message consumption (the >> message can be decoded and copied into the MPI user buffer _before_ it has >> been fully received). This method is currently a patent application, so I do >> not recommend you to copy-cat this method. > > Can u provide a link for this method? Atleast I can go through some details > of this technique. > > Go to http://portal.uspto.gov/external/portal/pair, have a look at > application 11/256752 and 11/437902. As stated above, you should understand > that these techniques are protected by patent legislation. > > > Håkon > -- 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
