From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sagi Grimberg Subject: Re: [PATCH 11/12] IB/core: add RW API support for signature MRs Date: Tue, 19 Apr 2016 21:46:08 +0300 Message-ID: <57167CF0.5090405@grimberg.me> References: <1461010463-6603-1-git-send-email-hch@lst.de> <1461010463-6603-12-git-send-email-hch@lst.de> <57163E99.8090301@grimberg.me> <20160419172627.GC20844@obsidianresearch.com> <20160419182950.GC989@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160419182950.GC989-jcswGhMUV9g@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Christoph Hellwig , Jason Gunthorpe Cc: dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, bart.vanassche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org, swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, target-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org >>> In isert if the we have a single sg entry, we use the local_dma_lkey >>> just so we can skip a registration (also for protection sg), perhaps >>> rdma_rw_init_one_mr can do this optimization too? >> >> Can't more than a single SG can be packed into a WR? Ideally this >> common code should try and max out the SG entries before falling back >> to using a WR? > > Mellanox signature MRs don't support registering more than a single SGE. It can theoretically, but large sg lists can potentially clog up the send queue in this case, and it would not perform as well as in the current scheme the driver has a smart repetition format optimization... -- 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