On Tue, Mar 05, 2019 at 09:53:01PM +0000, Parav Pandit wrote: > > > > -----Original Message----- > > From: Yuval Shaia <yuval.shaia@xxxxxxxxxx> > > Sent: Tuesday, March 5, 2019 5:09 AM > > To: Parav Pandit <parav@xxxxxxxxxxxx> > > Cc: Ira Weiny <ira.weiny@xxxxxxxxx>; Leon Romanovsky <leon@xxxxxxxxxx>; > > Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>; bvanassche@xxxxxxx; > > linux-rdma@xxxxxxxxxxxxxxx > > Subject: Re: [EXPERIMENTAL v1 0/4] RDMA loopback device > > > > > > > > > > Suggestion: To enhance 'loopback' performances, can you consider > > > > using shared memory or any other IPC instead of going thought the > > network stack? > > > > > > > Loopback driver in this patchset doesn't use network stack. > > > It is just 2000 lines of wrapper to memcpy() to enables applications to use > > rdma. > > > > To have a dedicated driver just for the loopback will force the user to do a > > smart select, i.e. to use lo device for local traffic and rxe for non-local. > No. when application is written using rdmacm, everything works based on the ip address. > It will pick the right rdma device that matches this ip. > It would be 'lo' when connections are on 127.0.0.1. > When application such as MPI, will have to anyway specify the which rdma device they want to use in system. But what if one wants to stay at the verb level and not use rdmacm API? See, QEMU's pvrdma device can't use rdmacm, i can explain why but it is for sure out of the scope of this thread. You can see it as a process such as ibv_rc_pingpong that one must specify the IB device he wants to use. Yuval
