From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ursula Braun Subject: Re: net/smc and the RDMA core Date: Wed, 3 May 2017 16:40:30 +0200 Message-ID: <93bd1bde-5ee5-cc6d-4db3-ba62e30ae49a@linux.vnet.ibm.com> References: <20170501163311.GA22209@lst.de> <1493750358.2552.13.camel@sandisk.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: "netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" To: Bart Van Assche , "hch-jcswGhMUV9g@public.gmane.org" , "davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org" Return-path: In-Reply-To: <1493750358.2552.13.camel-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On 05/02/2017 08:39 PM, Bart Van Assche wrote: > On Tue, 2017-05-02 at 14:25 +0200, Ursula Braun wrote: >> if you can point out specific issues, we will be happy to work with you >> to get them addressed! > > Hello Ursula, > > My list of issues that I would like to see addressed can be found below. Doug, > Christoph and others may have additional inputs. The issues that have not yet > been mentioned in other e-mails are: > - The SMC driver only supports one RDMA transport type (RoCE v1) but > none of the other RDMA transport types (RoCE v2, IB and iWARP). New > RDMA drivers should support all RDMA transport types transparently. > The traditional approach to support multiple RDMA transport types is > by using the RDMA/CM to establish connections. > - The implementation of the SMC driver only supports RoCEv1. This is > a very unfortunate choice because: > - RoCEv1 is not routable and hence is limited to a single Ethernet > broadcast domain. > - RoCEv1 packets escape a whole bunch of mechanisms that only work > for IP packets. Firewalls pass all RoCEv1 packets and switches > do not restrict RoCEv1 packets to a single VLAN. This means that > if the network configuration is changed after an SMC connection > has been set up such that IP communication between the endpoints > of an SMC connection is blocked that the SMC RoCEv1 packets will > not be blocked by the network equipment of which the configuration > has just been changed. > - As already mentioned by Christoph, the SMC implementation uses RDMA > calls that probably will be deprecated soon (ib_create_cq()) and > should use the RDMA R/W API instead of building sge lists itself. > > Bart. > Thanks for your list, we will take care of it! -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html