> -----Original Message----- > From: Yuval Shaia <yuval.shaia@xxxxxxxxxx> > Sent: Wednesday, March 6, 2019 1:31 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; Marcel Apfelbaum > <marcel.apfelbaum@xxxxxxxxx>; Kamal Heib <kheib@xxxxxxxxxx> > Subject: Re: [EXPERIMENTAL v1 0/4] RDMA loopback device > > 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? > Sure. He can stay at verb level where he anyway have to explicitly give the device name. > 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. > Yes, it is out of the scope here.
