From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH RFC 2/3] svcrdma: Use device rdma_read_access_flags Date: Wed, 11 Nov 2015 00:07:27 -0800 Message-ID: <20151111080727.GC31508@infradead.org> References: <1447152255-28231-3-git-send-email-sagig@mellanox.com> <20151110114145.GA2810@infradead.org> <5641D920.5000409@mellanox.com> <20151110120432.GA8230@infradead.org> <20151110182546.GI12667@obsidianresearch.com> <56425AFB.30202@talpey.com> <20151110211716.GA21631@obsidianresearch.com> <564261EF.4000008@talpey.com> <54CF0111-E9C4-4196-BF92-7E134A6A329A@oracle.com> <20151110235551.GA12795@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20151110235551.GA12795-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jason Gunthorpe Cc: Chuck Lever , Tom Talpey , Christoph Hellwig , Sagi Grimberg , Linux RDMA Mailing List List-Id: linux-rdma@vger.kernel.org On Tue, Nov 10, 2015 at 04:55:51PM -0700, Jason Gunthorpe wrote: > IMHO, the break point for when it makes sense to switch from a RDMA > READ chain to a MR is going to be a RDMA core tunable. The performance > curve won't have much to do with the ULP. core/device, a lot of it depends on when we'd exceed the nr_sge limit as well. But yes, it needs to move out ot the ULP and into the core, the ULP has no business here. As said a few times before we need a core API that takes a struct scatterlist and builds RDMA READ/WRITE requests from it in an efficient way. I have started talking to Sagi and preparing some build blocks for it, but getting all corner cases right will take a while. -- 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