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=-5.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 5D5DBC2D0C3 for ; Mon, 16 Dec 2019 15:01:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 32056206E0 for ; Mon, 16 Dec 2019 15:01:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ts/OM7nM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728215AbfLPPBR (ORCPT ); Mon, 16 Dec 2019 10:01:17 -0500 Received: from mail-il1-f196.google.com ([209.85.166.196]:46618 "EHLO mail-il1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728071AbfLPPBR (ORCPT ); Mon, 16 Dec 2019 10:01:17 -0500 Received: by mail-il1-f196.google.com with SMTP id t17so5624770ilm.13; Mon, 16 Dec 2019 07:01:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=Zn62EC+SRJNqnlXjqFaeTezjxELxXVZIr2BFFX93d7s=; b=ts/OM7nMG2XyF61v+PSyB7rzRYD2//G6jvqO5r5ysBw9AnsK3+MeY8EuLYDcot1e/q 0RDkKUaRCUH9CBA79lbTJRUvBsyHDygqskpkqRvtmvjasx6PmRZnRgpI+g8C6z1N4DQe SPyMhtRlniKzfN/kvz4hkqOsMA8Rr54mVeAsMdRK2KdxGW4H65fQGYob7CHUt+Q41Nfv av5PtUx5qlJGDnAJ3q/ZUaJydJE8LKord5MBJhtRdUKPlyi9a/OsOU6EsmKREFym5xp7 qePYwQIWROpCUEAHXsIaogN2iP57zAYlvig62uqGNB8md5AZg0vCZWFVbFcUwO/+jjHX oe+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Zn62EC+SRJNqnlXjqFaeTezjxELxXVZIr2BFFX93d7s=; b=SlqM25wV0OprVpVeVq34j5pH1oblJz4ivUMW0OiIJsVbJkcnzgocQppC35oZXujjF7 tG1WhINsiI4UGLf6znxPrFYitZ1N3tg9CFXEBR1YLUFFbJSeac+rpTKiZOA+ksoc8hnn g5lb7Smhyk/aOEVJriGUwUVArV3UAiBdqhk7Y6p6PCbzA8EW7JqQLy+Zxklyse6U3doP ohkerFBqvmbL7B0Sfr3Fv3YWgiBOo3ys84h8FBgNR61eymmQKM9LSrun4TN0bwdx65V2 aOhGj0C6ZMHuSfXMKGfQysj5h4lJZkGs1iVq3e4wPrxwEYtWhHI/gHoMO5G0hdQODcqX 15EQ== X-Gm-Message-State: APjAAAWJSnXckgD6lOLnbLegS+U2B6bkkeamQ1QugZJX61gHgWxW95Ij LtxSBFp/sBQ+kxLlspv473Q= X-Google-Smtp-Source: APXvYqxpEv++noZ9Rkk/ZXc5tQYObTgkWZ0UitIrJ+OJ5B7JFEPDDmVrNw3QkZg+QUg0nYqVuVr10g== X-Received: by 2002:a92:8b03:: with SMTP id i3mr12205907ild.7.1576508476311; Mon, 16 Dec 2019 07:01:16 -0800 (PST) Received: from ?IPv6:2601:284:8202:10b0:6046:f5bd:4635:2d5b? ([2601:284:8202:10b0:6046:f5bd:4635:2d5b]) by smtp.googlemail.com with ESMTPSA id j17sm5909468ild.45.2019.12.16.07.01.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 16 Dec 2019 07:01:15 -0800 (PST) Subject: Re: [PATCH bpf-next] samples/bpf: Attach XDP programs in driver mode by default To: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , Alexei Starovoitov , Daniel Borkmann Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, Jesper Dangaard Brouer References: <20191216110742.364456-1-toke@redhat.com> From: David Ahern Message-ID: <71b7ba89-7780-8ce1-1b30-67ae6ebc214c@gmail.com> Date: Mon, 16 Dec 2019 08:01:14 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: <20191216110742.364456-1-toke@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 12/16/19 4:07 AM, Toke Høiland-Jørgensen wrote: > When attaching XDP programs, userspace can set flags to request the attach > mode (generic/SKB mode, driver mode or hw offloaded mode). If no such flags > are requested, the kernel will attempt to attach in driver mode, and then > silently fall back to SKB mode if this fails. > > The silent fallback is a major source of user confusion, as users will try > to load a program on a device without XDP support, and instead of an error > they will get the silent fallback behaviour, not notice, and then wonder > why performance is not what they were expecting. > > In an attempt to combat this, let's switch all the samples to default to > explicitly requesting driver-mode attach. As part of this, ensure that all > the userspace utilities have a switch to enable SKB mode. For those that > have a switch to request driver mode, keep it but turn it into a no-op. > > Signed-off-by: Toke Høiland-Jørgensen > --- > samples/bpf/xdp1_user.c | 5 ++++- > samples/bpf/xdp_adjust_tail_user.c | 5 ++++- > samples/bpf/xdp_fwd_user.c | 17 ++++++++++++++--- > samples/bpf/xdp_redirect_cpu_user.c | 4 ++++ > samples/bpf/xdp_redirect_map_user.c | 5 ++++- > samples/bpf/xdp_redirect_user.c | 5 ++++- > samples/bpf/xdp_router_ipv4_user.c | 3 +++ > samples/bpf/xdp_rxq_info_user.c | 4 ++++ > samples/bpf/xdp_sample_pkts_user.c | 12 +++++++++--- > samples/bpf/xdp_tx_iptunnel_user.c | 5 ++++- > samples/bpf/xdpsock_user.c | 5 ++++- > 11 files changed, 58 insertions(+), 12 deletions(-) > Acked-by: David Ahern Thanks for doing this, Toke.