From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH v2] RDMA/cma: Make CM response timeout and # CM retries configurable Date: Thu, 13 Jun 2019 20:46:33 -0300 Message-ID: <20190613234633.GL22901@ziepe.ca> References: <20190226075722.1692315-1-haakon.bugge@oracle.com> <174ccd37a9ffa05d0c7c03fe80ff7170a9270824.camel@redhat.com> <67B4F337-4C3A-4193-B1EF-42FD4765CBB7@oracle.com> <20190613172355.GF22901@ziepe.ca> <1D8E6B14-3336-42B3-B572-596DD2183D89@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <1D8E6B14-3336-42B3-B572-596DD2183D89@oracle.com> Sender: linux-kernel-owner@vger.kernel.org To: =?utf-8?B?SMOla29u?= Bugge Cc: Doug Ledford , Leon Romanovsky , Parav Pandit , Steve Wise , OFED mailing list , linux-kernel@vger.kernel.org List-Id: linux-rdma@vger.kernel.org On Thu, Jun 13, 2019 at 07:39:24PM +0200, Håkon Bugge wrote: > > > > On 13 Jun 2019, at 19:23, Jason Gunthorpe wrote: > > > > On Thu, Jun 13, 2019 at 06:58:30PM +0200, Håkon Bugge wrote: > > > >> If you refer to the backlog parameter in rdma_listen(), I cannot see > >> it being used at all for IB. > >> > >> For CX-3, which is paravirtualized wrt. MAD packets, it is the proxy > >> UD receive queue length for the PF driver that can be construed as a > >> backlog. > > > > No, in IB you can drop UD packets if your RQ is full - so the proxy RQ > > is really part of the overall RQ on QP1. > > > > The backlog starts once packets are taken off the RQ and begin the > > connection accept processing. > > Do think we say the same thing. If, incoming REQ processing is > severly delayed, the backlog is #entries in the QP1 receive queue in > the PF. I can call rdma_listen() with a backlog of a zillion, but it > will not help. backlog and queue depth are different things, we shouldn't confuse them together.. Jason