I agree. SG --- Bernard Metzler <[EMAIL PROTECTED]> wrote:
> Sukanta, > > without touching any TOE issues (this question is > about RDMA, right?), > after > transforming a TCP connection into RDMA mode and > using an RDMA API, > the socket file descriptor is not longer to be used > for communication. > In fact, on some implementations the stream socket > resources will > even get released. That is, if the socket was the > direct consumer > of the TCP stream, then now it is RDMAP/DDP/MPA. > RDMA APIs such as IT-API defining a specific call to > convert a socket > based > connection into RDMA mode (e.g., > it_socket_convert()). > Other consumers may directly start via an RDMA API, > never > opening a consumer controlled socket. > > So, in RDMA mode, communication will happen via the > RDMA API. At this > stage, the kernel still have to keep completely in > its hands the > synchronisation of state information related to that > offloaded > connection(s) with the host stack (it would have to > protect the > local port used by the offloaded connection for > example, others > are routing, ARP, SNMP...), but it is not involved > at the data path. > > With respect to the kernel based TCP stack, what is > not needed is > a hack into the stack and scatter/gather state > information of the live > TCP connection between kernel and RNIC, but to find > one clean interface > to transfer state information out of that stack and > to the RNIC. > > > With limited benefit, one could of course also > implement native > sockets over RDMA, where an in-kernel midlayer on > top of kernel > RDMA Verbs is doing the translation between send(), > receive() to > post_send, post_receive. But usage of 'true RDMA' > operations > like RDMA READ or WRITE might be limited, and I > don't see much value > for the user here. One variety of this approach with > less limited > access to RMDA benefits might be sockets with > extended RDMA > semantics. > > Bernard. > > [EMAIL PROTECTED] wrote on > 27.05.2005 15:40:43: > > > Venkata, > > How will that work? If the RNIC offloads RDMA > and > > TCP completely from the Operating System and does > not > > share any state information then the application > > running on the host will never be in the position > to > > utilize the socket interface to use the > communication > > logic to send and receive data between the remote > node > > and itself. Some information needs to be shared. > How > > much of it and what exactly needs to be shared is > the > > question. > > > > Thanks > > SG > > > > --- Venkata Jagana <[EMAIL PROTECTED]> wrote: > > > > > > > > > > > > > > > > > > > > > [EMAIL PROTECTED] > wrote on > > > 05/25/2005 09:47:00 > > > PM: > > > > > > > Venkata, > > > > Interesting coincidence: I was talking with > > > someone (at HP) today > > > > who knows substantially more than I do about > > > RNICs. > > > > They indicated RNICs need to manage TCP state > on > > > the card from userspace. > > > > I suspect that's only possible through a > private > > > interface > > > > (e.g. ioctl() or /proc) or the non-existant > (in > > > kernel.org) > > > > TOE implementation. Is this correct? > > > > > > > > > > Not correct. > > > > > > Since RNICs are offloaded adapters with RDMA > > > protocols layered on > > > top of TCP stack, they do maintain the TCP state > > > internally but > > > it does not expose to the host. RNIC expose only > > > RNIC Verbs interface > > > to the host bot not TOE interface. > > > > > > Thanks > > > Venkat > > > > > > > > > > > hth, > > > > grant > > > > > > > > > > > > > > > > > > ------------------------------------------------------- > > > > SF.Net email is sponsored by: GoToMeeting - > the > > > easiest way to > > > collaborate > > > > online with coworkers and clients while > avoiding > > > the high cost of travel > > > and > > > > communications. There is no equipment to buy > and > > > you can meet as often as > > > > you want. Try it > > > > > > free.http://ads.osdn.com/?ad_id=7402&alloc_id=16135&op=click > > > > > _______________________________________________ > > > > Rdma-developers mailing list > > > > [EMAIL PROTECTED] > > > > > https://lists.sourceforge.net/lists/listinfo/rdma-developers > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! Mail has the best spam > protection around > > http://mail.yahoo.com > > > > > > > ------------------------------------------------------- > > This SF.Net email is sponsored by Yahoo. > > Introducing Yahoo! Search Developer Network - > Create apps using Yahoo! > > Search APIs Find out how you can build Yahoo! > directly into your own > > Applications - visit > http://developer.yahoo.net/?fr=offad-ysdn-ostg-q22005 > > _______________________________________________ > > Rdma-developers mailing list > > [EMAIL PROTECTED] > > > https://lists.sourceforge.net/lists/listinfo/rdma-developers > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
