From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [RFC v2 for accelerated IPoIB 00/6] Enhanced mode for IPoIB driver Date: Sun, 26 Mar 2017 14:42:37 -0600 Message-ID: <20170326204237.GB3113@obsidianresearch.com> References: <1490036908-12528-1-git-send-email-erezsh@mellanox.com> <20170320205927.GA17225@obsidianresearch.com> <20170321114955.GB2079@mtr-leonro.local> <20170321161530.GB22216@obsidianresearch.com> <20170321164952.GE2079@mtr-leonro.local> <20170322165238.GA26589@obsidianresearch.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: Erez Shitrit Cc: Leon Romanovsky , Erez Shitrit , Doug Ledford , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , valex-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org List-Id: linux-rdma@vger.kernel.org On Sun, Mar 26, 2017 at 07:17:13PM +0300, Erez Shitrit wrote: > > be computed once instead of computed for every split packet. The > > downside here is that it may be very complicated to store a kref in a > > skb pseudo header and properly unref it at all the right times.. > > It is an optimization, and still we need to get the ah even at the > middle of GSO, for each skb, or to keep it somewhere, also will need > to keep more space in the skb, more processing. GSO is done in a way where the pseudo header is retained but not recomputed for every fragment, much like for ethernet. Does mlx5 even need a 'AH'? Maybe allowing the driver to provide some bytes in the pseudo header that match the HW SQE is an overall more efficient direction. > > The other is to factor out the AH extraction from ipoib_start_xmit > > into a helper function and have all the rn drivers call it to get the > > AH. > > We will pay with performance degradation for each send. Eh? Having ndo->ipoib->driver or ndo->driver->ipoib as a call chain doesn't really matter one bit. 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