From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: Add PGM protocol support to the IP stack Date: Mon, 22 Mar 2010 17:36:09 +0100 Message-ID: <20100322163609.GZ20695@one.firstfloor.org> References: <87tysccjrn.fsf@basil.nowhere.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , David Miller , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Christoph Lameter Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, Mar 22, 2010 at 09:20:42AM -0500, Christoph Lameter wrote: > On Fri, 19 Mar 2010, Andi Kleen wrote: > > > Christoph Lameter writes: > > > > > > I know about the openpgm implementation. Openpbm does this at the user > > > level and requires linking to a library. It is essentially a communication > > > protocol done in user space. It has privilege issues because it has to > > > create PGM packets via a raw socket. > > > > That seems like a poor reason alone to put something into the kernel > > Perhaps you rather need some way to have unpriviledged raw sockets? > > Not the only reason. There are also performance implications. NAKing and > other control messages from user space are a pain and the available > implementations add numerous threads just to control the timing of control > messages and the expiration of data etc. Its difficult to listen to a PGM > port from user space. You have to get all messages for the PGM protocol > and then filter in each process. Ok that sounds like a good reason to have a kernel protocol. Thanks. Multicast reliable kernel protocols are somewhat new, I guess one would need to make sure to come up with a clean generic interface for them first. -Andi -- ak@linux.intel.com -- Speaking for myself only.