From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C822C3A59C for ; Thu, 15 Aug 2019 16:26:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5BF312084D for ; Thu, 15 Aug 2019 16:26:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731719AbfHOQ0A (ORCPT ); Thu, 15 Aug 2019 12:26:00 -0400 Received: from mga11.intel.com ([192.55.52.93]:18625 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731640AbfHOQZ7 (ORCPT ); Thu, 15 Aug 2019 12:25:59 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Aug 2019 09:25:58 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,389,1559545200"; d="scan'208";a="260862741" Received: from unknown (HELO [10.241.228.234]) ([10.241.228.234]) by orsmga001.jf.intel.com with ESMTP; 15 Aug 2019 09:25:57 -0700 Subject: Re: [PATCH bpf-next 0/5] Add support for SKIP_BPF flag for AF_XDP sockets To: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , magnus.karlsson@intel.com, bjorn.topel@intel.com, netdev@vger.kernel.org, bpf@vger.kernel.org, intel-wired-lan@lists.osuosl.org, maciej.fijalkowski@intel.com, tom.herbert@intel.com References: <1565840783-8269-1-git-send-email-sridhar.samudrala@intel.com> <87ftm2adi2.fsf@toke.dk> From: "Samudrala, Sridhar" Message-ID: Date: Thu, 15 Aug 2019 09:25:57 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <87ftm2adi2.fsf@toke.dk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 8/15/2019 4:12 AM, Toke Høiland-Jørgensen wrote: > Sridhar Samudrala writes: > >> This patch series introduces XDP_SKIP_BPF flag that can be specified >> during the bind() call of an AF_XDP socket to skip calling the BPF >> program in the receive path and pass the buffer directly to the socket. >> >> When a single AF_XDP socket is associated with a queue and a HW >> filter is used to redirect the packets and the app is interested in >> receiving all the packets on that queue, we don't need an additional >> BPF program to do further filtering or lookup/redirect to a socket. >> >> Here are some performance numbers collected on >> - 2 socket 28 core Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz >> - Intel 40Gb Ethernet NIC (i40e) >> >> All tests use 2 cores and the results are in Mpps. >> >> turbo on (default) >> --------------------------------------------- >> no-skip-bpf skip-bpf >> --------------------------------------------- >> rxdrop zerocopy 21.9 38.5 >> l2fwd zerocopy 17.0 20.5 >> rxdrop copy 11.1 13.3 >> l2fwd copy 1.9 2.0 >> >> no turbo : echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo >> --------------------------------------------- >> no-skip-bpf skip-bpf >> --------------------------------------------- >> rxdrop zerocopy 15.4 29.0 >> l2fwd zerocopy 11.8 18.2 >> rxdrop copy 8.2 10.5 >> l2fwd copy 1.7 1.7 >> --------------------------------------------- > > You're getting this performance boost by adding more code in the fast > path for every XDP program; so what's the performance impact of that for > cases where we do run an eBPF program? The no-skip-bpf results are pretty close to what i see before the patches are applied. As umem is cached in rx_ring for zerocopy the overhead is much smaller compared to the copy scenario where i am currently calling xdp_get_umem_from_qid(). > > Also, this is basically a special-casing of a particular deployment > scenario. Without a way to control RX queue assignment and traffic > steering, you're basically hard-coding a particular app's takeover of > the network interface; I'm not sure that is such a good idea... Yes. This is mainly targeted for application that create 1 AF_XDP socket per RX queue and can use a HW filter (via ethtool or TC flower) to redirect the packets to a queue or a group of queues. > > -Toke >