From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: NFSD generic R/W API (sendto path) performance results Date: Thu, 17 Nov 2016 13:46:02 +0100 Message-ID: <20161117124602.GA25821@lst.de> References: <9170C872-DEE1-4D96-B9D8-E9D2B3F91915@oracle.com> <024601d23f7f$cef62500$6ce26f00$@opengridcomputing.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: Chuck Lever Cc: Steve Wise , Christoph Hellwig , Sagi Grimberg , List Linux RDMA Mailing List-Id: linux-rdma@vger.kernel.org On Wed, Nov 16, 2016 at 02:45:33PM -0500, Chuck Lever wrote: > Out of curiosity, I hacked up my NFS client to limit the size of RDMA > segments to 30 pages (the server HCA's max_sge). > > A 1MB NFS READ now takes 9 segments. That forces the after-conversion > server to build single-Write chains and use 9 post_send calls to > transmit the READ payload, just like the before-conversion server. > > Performance of before- and after-conversion servers is now equivalent. > > kB reclen write rewrite read reread > 2097152 1024 1061237 1141614 1961410 2000223 What HCA is this, btw? Also did you try to always register for > max_sge calls? The code can already register all segments with the rdma_rw_force_mr module option, so it would only need a small tweak for that behavior. -- 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