From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: ib_post_send in drivers Date: Sat, 21 Nov 2009 13:01:28 -0700 Message-ID: <20091121200128.GD1966@obsidianresearch.com> References: <4B06C0EA.2070501@systemfabricworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Bart Van Assche Cc: Sean Hefty , frank zago , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org On Sat, Nov 21, 2009 at 12:17:32PM +0100, Bart Van Assche wrote: > ib_post_send() has to request a completion notification for each WR, > which has a negative performance impact. My opinion is that the > current behavior makes ib_post_send() easier to implement, while the > behavior specified in the IBAS is more interesting for applications > that use the verbs API. It seems to me an error return from ib_post_send either means the caller is asking for something impossible, or the QP is wrecked, and is thus pretty much non-recoverable. For instance all the errors for mlx4 fit this pattern - and I think that is a reasonable requirement for any implementation of ib_post_send. So in that light the absence/presence of a completion does not seem important - if you get an error back you should always tear down the QP. Are SRP/etc calling ib_post_send in a way that ever returns errors? 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