From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roland Dreier Subject: Re: strong ordering for data registered memory Date: Wed, 11 Nov 2009 09:57:23 -0800 Message-ID: References: <4AF9CACE.8070700@Sun.COM> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <4AF9CACE.8070700-UdXhSnd/wVw@public.gmane.org> (David Brean's message of "Tue, 10 Nov 2009 15:19:26 -0500") Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: David Brean Cc: linux-rdma List-Id: linux-rdma@vger.kernel.org > Some time ago there was an email sent to this group with the subject > "weak ordering for data registered memory". I don't recall any action > resulting from this thread. So, I have a question. If a bit were > defined to specify "strong ordering", perhaps as a "access" flag (see > ibv_access_flags) and used with ibv_reg_mr(), would that be sufficient > for (1) client applications that need a HW "guarantee" of writing the > last byte of an RDMA last and (2) platform implementations that need > to deliver that feature? What would happen if an application asked for strong ordering and the adapter and/or platform is not capable of that? Weak ordering is a bit easier to handle -- the app is saying "if you can make things go faster, don't worry about ordering here" and a platform where it doesn't matter can just ignore it. - R. -- 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