From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: is it possible to avoid syncing after an rdma write? Date: Tue, 16 Feb 2010 18:12:24 -0700 Message-ID: <20100217011224.GH16490@obsidianresearch.com> References: <4B7B2A6C.80101@oracle.com> <20100217005827.GF16490@obsidianresearch.com> <002101caaf6d$47bc0180$d7340480$@com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <002101caaf6d$47bc0180$d7340480$@com> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Paul Grun Cc: 'Andy Grover' , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org On Tue, Feb 16, 2010 at 05:05:21PM -0800, Paul Grun wrote: > Why not use an RDMA write w/ immed? That forces the consumption of a > receive WQE and can be used to create a completion event. Since the > immediate data is carried in the last packet of a multi-packet RDMA write, > you are guaranteed that all data has been placed in the receive buffer, in > order. Yes, RDMA WRITE w/ immediate data is perfectly fine. I've even implemented some protocols that use it to good effect. Not sure what the performance trade off is like though. The immediate data pretty much behaves exactly like a SEND WC on the receive side, but there may be some performance and latency advantages, particularly on the send side. 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