Return-Path: Received: from quartz.orcorp.ca ([184.70.90.242]:33948 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750742AbdIGPIl (ORCPT ); Thu, 7 Sep 2017 11:08:41 -0400 Date: Thu, 7 Sep 2017 09:08:29 -0600 From: Jason Gunthorpe To: Tom Talpey Cc: Chuck Lever , Sagi Grimberg , linux-rdma , Linux NFS Mailing List Subject: Re: [PATCH RFC 0/5] xprtrdma Send completion batching Message-ID: <20170907150829.GA20644@obsidianresearch.com> References: <20170905164347.11106.27140.stgit@manet.1015granger.net> <1230f9d9-07c1-6d00-b197-f408712fb5c1@grimberg.me> <890CC58C-7F8F-4B7E-8620-21F07007D3AA@oracle.com> <6dcdcc25-2613-cdb5-1db2-6c944f05242b@grimberg.me> <4E2E5580-69A5-4C3B-9FCA-E61AE2042E6B@oracle.com> <9059315f-1985-042e-a59f-26a66fbece3e@grimberg.me> <5B2F42B8-2CBD-43F4-BBAD-71EDD4F871FB@oracle.com> <20170906193946.GC18461@obsidianresearch.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Sep 07, 2017 at 09:17:16AM -0400, Tom Talpey wrote: > >Why is waiting for the send completion so fundamentally different from > >waiting for the remote RPC reply? > > > >I would say that 99% of time the send completion and RPC reply > >completion will occure approximately concurrently. > > Absolutely not. The RPC reply requires upper layer processing at > the server, which involves work requests, context switches, file I should have said '99% of the time the SEND will occure approximately concurrently or sooner' Jason