From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id EC84242AF8; Wed, 17 May 2023 01:38:56 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 7C905410E4; Wed, 17 May 2023 01:38:56 +0200 (CEST) Received: from mail.redfish-solutions.com (mail.redfish-solutions.com [24.116.100.90]) by mails.dpdk.org (Postfix) with ESMTP id 41D9040EE1 for ; Wed, 17 May 2023 01:38:55 +0200 (CEST) Received: from smtpclient.apple (macbook3-3.redfish-solutions.com [192.168.8.12]) (authenticated bits=0) by mail.redfish-solutions.com (8.17.1/8.16.1) with ESMTPSA id 34GNcqgA584567 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 16 May 2023 17:38:52 -0600 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3731.500.231\)) Subject: Re: DPDK packaging and OpenWrt From: Philip Prindeville In-Reply-To: <470f0311-ed76-4134-8d62-f4db7269f1d6@Spark> Date: Tue, 16 May 2023 17:38:41 -0600 Cc: dev@dpdk.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <60A57C56-D30C-4B0F-BAE9-01BA6FD16E66@redfish-solutions.com> <470f0311-ed76-4134-8d62-f4db7269f1d6@Spark> To: "Garrett D'Amore" X-Mailer: Apple Mail (2.3731.500.231) X-Scanned-By: MIMEDefang 3.3 on 192.168.8.3 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org > On May 16, 2023, at 5:06 PM, Garrett D'Amore = wrote: >=20 > On May 16, 2023 at 12:19 PM -0700, Philip Prindeville = , wrote: > [snip] >=20 > 3. Is "uio_pci_generic.ko" worth the potential insecurity/instability = of a misbehaving application? My understanding is that it's only needed = on SR-IOV hardware where MSI/MSI-X interrupts aren't supported: is there = even any current hardware that doesn't support MSI/MSI-X? Or am I = misunderstanding the use case?=20 > *Either* uio_pci_generic *or* vfio with NOIOMMU are required for the = vary large number of systems that either lack an IOMMU (btw, that will = be nearly all OpenWRT platforms!), or elect to run with the iommu = unconfigured (one justification for doing that - apart from numerous = software bugs and limitations =E2=80=94 is that the IOMMU can slow down = I/O. We actually recommend most of our customers that run dedicated = systems run with the IOMMU disabled for this reason.) >=20 > vfio with noiommu is preferable. I could build with CONFIG_NOIOMMU=3Dn and then package the modprobe = .conf file (or the grub command-line, etc) to have = enable_unsafe_noiommu_mode=3D1, right? This would accomplish the same thing at run-time, but allow the module = to be built to be used either with or without an IOMMU? That's per: https://dpdk-guide.gitlab.io/dpdk-guide/setup/binding.html But I don't know how recent that advice is... >=20 > 4. Can most functionality be achieved with VFIO + IOMMU support?=20 > *If* you have an IOMMU, and you aren=E2=80=99t trying to eke the very = last bits of performance, yes. But as many systems don=E2=80=99t have = an IOMMU, and as one of the main points of DPDK are extremely = performance sensitive applications, I think the answer is more broadly, = =E2=80=9Cno=E2=80=9D. > 11. What is the user-space TCP/IP stack of choice (or reference) for = use with DPDK?=20 > IMO, if you=E2=80=99re using DPDK to run *TCP* applications then = you=E2=80=99re probably misusing it =E2=80=94 there isn=E2=80=99t a user = land TCP stack that I would trust. IP/UDP is something we do, and it = works well, but I can tell you already it=E2=80=99s a pain to do *just* = IP, because e.g. routing tables, ARP, etc. all have to be handled.=20 > =E2=80=A2 Garrett Yeah, good point. Are there shims to use with FRR, lldpd, et al for = example?