From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v2 net-next] net: introduce gro_frag_list_enable sysctl Date: Tue, 29 Oct 2013 22:34:56 -0400 (EDT) Message-ID: <20131029.223456.778268322772629087.davem@davemloft.net> References: <20131030020543.GA1925@gondor.apana.org.au> <20131030021905.GA2089@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: hkchu@google.com, eric.dumazet@gmail.com, christoph.paasch@uclouvain.be, netdev@vger.kernel.org, mwdalton@google.com To: herbert@gondor.apana.org.au Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:52239 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751839Ab3J3Ce5 (ORCPT ); Tue, 29 Oct 2013 22:34:57 -0400 In-Reply-To: <20131030021905.GA2089@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: From: Herbert Xu Date: Wed, 30 Oct 2013 10:19:06 +0800 > On Tue, Oct 29, 2013 at 07:13:50PM -0700, Jerry Chu wrote: >> On Tue, Oct 29, 2013 at 7:05 PM, Herbert Xu wrote: >> >> > If we are indeed able to do that, I doubt we would even need >> > the sysctl patch since the GRO performance should be vastly >> > superior to the non-GRO case, even for a router/bridge. >> >> Probably not the case for the simple forwarding case. See my >> test result of some small (5-8%) CPU+throughput penalty from >> GRO (over GRE tunnel) posted previously. But I can believe >> the number may be very different if the forwarding path involves >> more work (NAT, iptables filtering,...,etc) resulting in a higher per >> pkt cost. > > Your numbers are with Eric's current patch that just linearises > the packet, what I'm saying is that you don't need to linearise > these packets since the packet boundaries are still there, just > hidden inside each frag_list. Agreed.