From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH WIP 38/43] iser-target: Port to new memory registration API Date: Thu, 23 Jul 2015 10:31:24 -0600 Message-ID: <20150723163124.GD25174@obsidianresearch.com> References: <1437548143-24893-1-git-send-email-sagig@mellanox.com> <1437548143-24893-39-git-send-email-sagig@mellanox.com> <20150722170413.GE6443@infradead.org> <55AFD3DC.8070508@dev.mellanox.co.il> <20150722175755.GH26909@obsidianresearch.com> <55B0C18B.4080901@dev.mellanox.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <55B0C18B.4080901-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sagi Grimberg Cc: Christoph Hellwig , Sagi Grimberg , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Liran Liss , Oren Duer List-Id: linux-rdma@vger.kernel.org On Thu, Jul 23, 2015 at 01:27:23PM +0300, Sagi Grimberg wrote: > >ib_post_fastreg_wr would be a function that needs 3 register passed > >arguments and does a simple copy to the driver's actual sendq > > That will require to take the SQ lock and write a doorbell for each > registration and post you want to do. I'm confident that constructing > a post chain with a single sq lock acquire and a single doorbell will > be much much better even with conditional jumps and memsets. You are still thinking at a micro level, the ULP should be working at a higher level and requesting the MR(s) and the actual work together so the driver can run the the whole chain of posts without extra stack traffic, locking or doorbells. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html