On 05/01/2017 07:55 PM, Parav Pandit wrote: > Hi Bart, Ursula, Dave, > > I am particularly concerned about SMC as address family. > It should not be treated as address family, but rather an additional protocol similar for socket type SOCK_STREAM. We tried to avoid changes of the kernel TCP code. A new address family seemed to be a feasible way to achieve this. > While doing performance benchmarking last month and while porting few database application, > > I encountered a major hurdle where user space library heavily depend on AF_INET and AF_INET6 family through get_addrinfo and other friend functions. > Adding or treating AF_SMC as AF_INET just doesn't sound right. > > Most user space code doesn't care for the protocol field, but do handle domain field. > > I personally believe it's not too late to modify SMC to drop expose AF_SMC and have it exposed through new protocol that can be exposed through socket() API. > > Parav > >> -----Original Message----- >> From: linux-rdma-owner@xxxxxxxxxxxxxxx [mailto:linux-rdma- >> owner@xxxxxxxxxxxxxxx] On Behalf Of Bart Van Assche >> Sent: Monday, May 1, 2017 12:30 PM >> To: hch@xxxxxx; davem@xxxxxxxxxxxxx; ubraun@xxxxxxxxxxxxxxxxxx >> Cc: netdev@xxxxxxxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx >> Subject: Re: net/smc and the RDMA core >> >> On Mon, 2017-05-01 at 18:33 +0200, Christoph Hellwig wrote: >>> Hi Ursual, hi netdev reviewers, >>> >>> how did the smc protocol manage to get merged without any review on >>> linux-rdma at all? As the results it seems it's very substandard in >>> terms of RDMA API usage, e.g. it neither uses the proper CQ API nor >>> the RDMA R/W API, and other will probably find additional issues as >>> well. >> >> Hello Dave and Ursula, >> >> It seems very rude to me to have merged the SMC protocol driver without >> having involved the linux-rdma community. Anyway, I have the following >> questions for Dave and Ursula: >> * Since the Linux kernel is standards based: where can we find the standard >> that defines the SMC wire protocol? If this protocol has not been >> standardized yet: in what file (other than *.[ch]) in the Linux kernel >> tree has this protocol been documented? >> * What are the differences between the SMC protocol, the SDP protocol and >> the rsockets protocol? How do existing implementations for these protocols >> compare to each other from a performance point of view? If no performance >> comparison between these protocols is available, shouldn't the performance >> of these protocols have been compared with each other before a review of >> the SMC driver even started? >> * What are the reasons why the SDP driver was never accepted upstream? Do >> the arguments why SDP was not accepted upstream also apply to the SMC >> driver (SDP = Sockets Direct Protocol)? >> * Since SMC has to be selected by specifying AF_SMC, how are users expected >> to specify whether AF_INET, AF_INET6 or yet another address family should >> be used to set up a connection between SMC endpoints? >> * Is the SMC driver limited to RoCE? Are you aware that the rsockets library >> supports multiple transport layers (RoCE, IB and iWARP)? >> * Since functionality that is similar what the SMC driver provides already >> exists in user space (rsockets), why has this functionality been >> reimplemented as a kernel driver (SMC)? >> >> Bart.-- >> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body >> of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at >> http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
