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=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, 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 3F85CC2D0E4 for ; Fri, 27 Nov 2020 04:37:03 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6B46222228 for ; Fri, 27 Nov 2020 04:37:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="i/yPdzD3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B46222228 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42948 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kiVVE-0001sz-G9 for qemu-devel@archiver.kernel.org; Thu, 26 Nov 2020 23:37:00 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:44922) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kiVUW-0001SS-A3 for qemu-devel@nongnu.org; Thu, 26 Nov 2020 23:36:16 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:43581) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kiVUT-0007Sq-Lx for qemu-devel@nongnu.org; Thu, 26 Nov 2020 23:36:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606451771; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XRuu/DzTIdeVKZHpmq+1+MpFrj/bdehTax4q1yNxD7M=; b=i/yPdzD3frqPBQlC/YGetGXGnZgAXKj+RIOIKkOxO/ZVT9zFcfXhVHMMuNRtBUq6D8gy6X PXCMvXRvmDcVgRFxnwAZNIIz4MaF+GxuE5ANFeIS9tx3Ll1uzlJQSJ+Qngo5ptUwRfA6Lp cNvXHsSzN2xD+ENOes9sNEjEa1betJw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-501-WpQPTqHGMRC8lWcgZusvXQ-1; Thu, 26 Nov 2020 23:36:06 -0500 X-MC-Unique: WpQPTqHGMRC8lWcgZusvXQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 985161842145; Fri, 27 Nov 2020 04:36:05 +0000 (UTC) Received: from [10.72.13.168] (ovpn-13-168.pek2.redhat.com [10.72.13.168]) by smtp.corp.redhat.com (Postfix) with ESMTP id 53ADE5C1C2; Fri, 27 Nov 2020 04:35:59 +0000 (UTC) Subject: Re: [RFC PATCH v2 0/5] eBPF RSS support for virtio-net To: Yuri Benditovich References: <20201119111305.485202-1-andrew@daynix.com> From: Jason Wang Message-ID: <12187c50-94ce-e456-4c48-5497f2f2caee@redhat.com> Date: Fri, 27 Nov 2020 12:35:58 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Received-SPF: pass client-ip=216.205.24.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Yan Vugenfirer , Andrew Melnychenko , qemu-devel@nongnu.org, "Michael S . Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/11/26 下午8:52, Yuri Benditovich wrote: > > > On Mon, Nov 23, 2020 at 8:08 AM Jason Wang > wrote: > > > On 2020/11/19 下午7:13, Andrew Melnychenko wrote: > > This set of patches introduces the usage of eBPF for packet steering > > and RSS hash calculation: > > * RSS(Receive Side Scaling) is used to distribute network packets to > > guest virtqueues by calculating packet hash > > * Additionally adding support for the usage of RSS with vhost > > > > The eBPF works on kernels 5.8+ > > On earlier kerneld it fails to load and the RSS feature is reported > > only without vhost and implemented in 'in-qemu' software. > > > > Implementation notes: > > Linux TAP TUNSETSTEERINGEBPF ioctl was used to set the eBPF program. > > Added libbpf dependency and eBPF support. > > The eBPF program is part of the qemu and presented as an array > > of BPF ELF file data. > > The compilation of eBPF is not part of QEMU build and can be done > > using provided Makefile.ebpf(need to adjust 'linuxhdrs'). > > Added changes to virtio-net and vhost, primary eBPF RSS is used. > > 'in-qemu' RSS used in the case of hash population and as a > fallback option. > > For vhost, the hash population feature is not reported to the guest. > > > > Please also see the documentation in PATCH 5/5. > > > > I am sending those patches as RFC to initiate the discussions > and get > > feedback on the following points: > > * Fallback when eBPF is not supported by the kernel > > * Live migration to the kernel that doesn't have eBPF support > > * Integration with current QEMU build > > * Additional usage for eBPF for packet filtering > > > > Known issues: > > * hash population not supported by eBPF RSS: 'in-qemu' RSS used > > as a fallback, also, hash population feature is not reported to > guests > > with vhost. > > * big-endian BPF support: for now, eBPF isn't supported on > > big-endian systems. Can be added in future if required. > > * huge .h file with eBPF binary. The size of .h file containing > > eBPF binary is currently ~5K lines, because the binary is built > with debug information. > > The binary without debug/BTF info can't be loaded by libbpf. > > We're looking for possibilities to reduce the size of the .h files. > > > A question here, is this because the binary file contains DWARF > data? If > yes, is it a building or loading dependency? If it's latter, maybe we > can try to strip them out, anyhow it can't be recognized by kernel. > > Thanks > > > After some experiments we can see that stripping of debug sections > reduces the size of > ELF from ~45K to ~20K (we tried to strip more but the libbpf fails to > load it, libbpf needs BTF and symbols) > So I suggest to reevaluate the necessity of libbpf. > For this specific BPF it does not present advantage and we hardly can > create some reusable code > related to libbpf, i.e. any further BPF will need its own libbpf wrapper. > The BTF is really good feature and in case some later BPF will need an > access to kernel > structures it will use libbpf loader. > What you think about it? If we can find a way to use BTF without libbpf, it should be acceptable. Thanks > > > > > Changes since v1: > > * using libbpf instead of direct 'bpf' system call. > > * added libbpf dependency to the configure/meson scripts. > > * changed python script for eBPF .h file generation. > > * changed eBPF program - reading L3 proto from ethernet frame. > > * added TUNSETSTEERINGEBPF define for TUN. > > * changed the maintainer's info. > > * added license headers. > > * refactored code. > > > > Andrew (5): > >    net: Added SetSteeringEBPF method for NetClientState. > >    ebpf: Added eBPF RSS program. > >    ebpf: Added eBPF RSS loader. > >    virtio-net: Added eBPF RSS to virtio-net. > >    docs: Added eBPF RSS documentation. > > > >   MAINTAINERS                    |    7 + > >   configure                      |   33 + > >   docs/ebpf_rss.rst              |  133 + > >   ebpf/EbpfElf_to_C.py           |   36 + > >   ebpf/Makefile.ebpf             |   33 + > >   ebpf/ebpf_rss-stub.c           |   40 + > >   ebpf/ebpf_rss.c                |  186 ++ > >   ebpf/ebpf_rss.h                |   44 + > >   ebpf/meson.build               |    1 + > >   ebpf/rss.bpf.c                 |  505 +++ > >   ebpf/tun_rss_steering.h        | 5439 > ++++++++++++++++++++++++++++++++ > >   hw/net/vhost_net.c             |    2 + > >   hw/net/virtio-net.c            |  120 +- > >   include/hw/virtio/virtio-net.h |    4 + > >   include/net/net.h              |    2 + > >   meson.build                    |   11 + > >   net/tap-bsd.c                  |    5 + > >   net/tap-linux.c                |   13 + > >   net/tap-linux.h                |    1 + > >   net/tap-solaris.c              |    5 + > >   net/tap-stub.c                 |    5 + > >   net/tap.c                      |    9 + > >   net/tap_int.h                  |    1 + > >   net/vhost-vdpa.c               |    2 + > >   24 files changed, 6633 insertions(+), 4 deletions(-) > >   create mode 100644 docs/ebpf_rss.rst > >   create mode 100644 ebpf/EbpfElf_to_C.py > >   create mode 100755 ebpf/Makefile.ebpf > >   create mode 100644 ebpf/ebpf_rss-stub.c > >   create mode 100644 ebpf/ebpf_rss.c > >   create mode 100644 ebpf/ebpf_rss.h > >   create mode 100644 ebpf/meson.build > >   create mode 100644 ebpf/rss.bpf.c > >   create mode 100644 ebpf/tun_rss_steering.h > > >