From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Subject: Re: TCP IP Offloading Interface Date: Sun, 13 Jul 2003 16:53:23 -0700 Sender: linux-net-owner@vger.kernel.org Message-ID: <20030713165323.3fc2601f.davem@redhat.com> References: <20030713004818.4f1895be.davem@redhat.com> <52u19qwg53.fsf@topspin.com> <20030713160200.571716cf.davem@redhat.com> <20030713233503.GA31793@work.bitmover.com> <20030713164003.21839eb4.davem@redhat.com> <20030713235424.GB31793@work.bitmover.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: lm@bitmover.com, roland@topspin.com, alan@storlinksemi.com, linux-kernel@vger.kernel.org, linux-net@vger.kernel.org, netdev@oss.sgi.com Return-path: To: Larry McVoy In-Reply-To: <20030713235424.GB31793@work.bitmover.com> List-Id: netdev.vger.kernel.org On Sun, 13 Jul 2003 16:54:24 -0700 Larry McVoy wrote: > Every time I tried to push the page flip idea or offloading or any of > that crap, Andy Bechtolsheim would tell "the CPUs will get faster faster > than you can make that work". He was right. I really don't see why receive is so much of a big deal compared to send, and we do a send side version of this stuff already with zero problems. The NFS code is already basically ready to handle a fragmented packet (headers + pages), and could stick the page part into the page cache easily on receive. And it's not the CPUs that really limit us here, it's memory bandwidth. It's one thing to have a PCI-X bus fast enough to service 10Ggb/sec rates, it's yet another thing to have a memory bus and RAM underneath that which can handle moving that data over it _twice_. The infrastructure needed to support this on the networking side help us support other useful things, such as driver local packet buffer recycling.