From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from quartz.orcorp.ca ([184.70.90.242]:44610 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751457AbdIFTjw (ORCPT ); Wed, 6 Sep 2017 15:39:52 -0400 Date: Wed, 6 Sep 2017 13:39:46 -0600 From: Jason Gunthorpe To: Chuck Lever Cc: Sagi Grimberg , linux-rdma , Linux NFS Mailing List Subject: Re: [PATCH RFC 0/5] xprtrdma Send completion batching Message-ID: <20170906193946.GC18461@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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <5B2F42B8-2CBD-43F4-BBAD-71EDD4F871FB@oracle.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, Sep 06, 2017 at 02:33:50PM -0400, Chuck Lever wrote: > B. Force RPC completion to wait for Send completion, which > would allow the post-v4.6 scatter-gather code to work > safely. This would need some guarantee that Sends will > always complete in a short period. 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. eg It is quite likely the RPC reply SEND carries an embeded ack for the requesting SEND.. Jason From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH RFC 0/5] xprtrdma Send completion batching Date: Wed, 6 Sep 2017 13:39:46 -0600 Message-ID: <20170906193946.GC18461@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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <5B2F42B8-2CBD-43F4-BBAD-71EDD4F871FB-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Chuck Lever Cc: Sagi Grimberg , linux-rdma , Linux NFS Mailing List List-Id: linux-rdma@vger.kernel.org On Wed, Sep 06, 2017 at 02:33:50PM -0400, Chuck Lever wrote: > B. Force RPC completion to wait for Send completion, which > would allow the post-v4.6 scatter-gather code to work > safely. This would need some guarantee that Sends will > always complete in a short period. 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. eg It is quite likely the RPC reply SEND carries an embeded ack for the requesting SEND.. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html