From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: Re: [PATCH openvswitch] netlink: Implement & enable memory mapped netlink i/o Date: Wed, 27 Nov 2013 23:51:20 +0100 Message-ID: <52967768.8090308@redhat.com> References: <2336aeee25d64eab89302c28c33b7cb7d1a55560.1385057738.git.tgraf@redhat.com> <20131125230253.GR1435@nicira.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Cc: dev-yBygre7rU0TnMu66kgdUjQ@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, fleitner-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org To: Ben Pfaff Return-path: In-Reply-To: <20131125230253.GR1435-l0M0P4e3n4LQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dev-bounces-yBygre7rU0TnMu66kgdUjQ@public.gmane.org Errors-To: dev-bounces-yBygre7rU0TnMu66kgdUjQ@public.gmane.org List-Id: netdev.vger.kernel.org On 11/26/2013 12:02 AM, Ben Pfaff wrote: > On Thu, Nov 21, 2013 at 07:16:54PM +0100, Thomas Graf wrote: >> Based on the initial patch by Cong Wang posted a couple of months >> ago. >> >> This is the user space counterpart needed for the kernel patch >> '[PATCH net-next 3/8] openvswitch: Enable memory mapped Netlink i/o' >> >> Allows the kernel to construct Netlink messages on memory mapped >> buffers and thus avoids copying. The functionality is enabled on >> sockets used for unicast traffic. >> >> Further optimizations are possible by avoiding the copy into the >> ofpbuf after reading. >> >> Cc: Cong Wang >> Signed-off-by: Thomas Graf > > Does this depend on other patches or some specific Linux kernel > headers? It doesn't build here on GCC (similar results with Clang): Yes, it depends on a sufficiently recent . We can either #ifdef the mmap code or we provide a local copy of in include/linux. The code automatically falls back if the kernel does not support NL MMAP so that seems superior. What do you prefer?