From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: Re: [PATCH v4 net-next RFC] net: Generic XDP Date: Wed, 19 Apr 2017 10:44:59 -0700 Message-ID: <58F7A21B.9060309@gmail.com> References: <20170415005949.GB73685@ast-mbp.thefacebook.com> <20170418190535.GG4730@C02RW35GFVH8.dhcp.broadcom.net> <20170418.150708.1605529107204449972.davem@davemloft.net> <20170418.152916.1361453741909754079.davem@davemloft.net> <20170419142903.GJ4730@C02RW35GFVH8.dhcp.broadcom.net> <20170419171753.GA12838@ast-mbp.thefacebook.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: David Miller , michael.chan@broadcom.com, netdev@vger.kernel.org, xdp-newbies@vger.kernel.org To: Alexei Starovoitov , Andy Gospodarek Return-path: Received: from mail-io0-f196.google.com ([209.85.223.196]:34637 "EHLO mail-io0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S968618AbdDSRpV (ORCPT ); Wed, 19 Apr 2017 13:45:21 -0400 In-Reply-To: <20170419171753.GA12838@ast-mbp.thefacebook.com> Sender: netdev-owner@vger.kernel.org List-ID: On 17-04-19 10:17 AM, Alexei Starovoitov wrote: > On Wed, Apr 19, 2017 at 10:29:03AM -0400, Andy Gospodarek wrote: >> >> I ran this on top of a card that uses the bnxt_en driver on a desktop >> class system with an i7-6700 CPU @ 3.40GHz, sending a single stream of >> UDP traffic with flow control disabled and saw the following (all stats >> in Million PPS). >> >> xdp1 xdp2 xdp_tx_tunnel >> Generic XDP 7.8 5.5 (1.3 actual) 4.6 (1.1 actual) >> Optimized XDP 11.7 9.7 4.6 > > Nice! Thanks for testing. > >> One thing to note is that the Generic XDP case shows some different >> results for reported by the application vs actual (seen on the wire). I >> did not debug where the drops are happening and what counter needs to be >> incremented to note this -- I'll add that to my TODO list. The >> Optimized XDP case does not have a difference in reported vs actual >> frames on the wire. > > The missed packets are probably due to xmit queue being full. > We need 'xdp_tx_full' counter in: > + if (free_skb) { > + trace_xdp_exception(dev, xdp_prog, XDP_TX); > + kfree_skb(skb); > + } > like in-driver xdp does. > It's surprising that tx becomes full so often. May be bnxt specific behavior? hmm as a data point I get better numbers than 1.3Mpps running through the qdisc layer with pktgen so seems like something is wrong with the driver perhaps? If I get a chance I'll take a look with my setup here, although it likely wont be until the weekend. I don't think it needs to slow down dropping the RFC tag and getting the patch applied though. > >> I agree with all those who have asserted that this is great tool for >> those that want to get started with XDP but do not have hardware, so I'd >> say it's ready to have the 'RFC' tag dropped. Thanks for pushing this >> forward, Dave! :-) > > +1 > >