From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by mail.toke.dk (Postfix) with ESMTPS id 7C7CBA2E72A for ; Wed, 4 Oct 2023 20:08:54 +0200 (CEST) Authentication-Results: mail.toke.dk; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=rHzpZAiV Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 2BE8061668; Wed, 4 Oct 2023 18:08:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 65CE1C433C9; Wed, 4 Oct 2023 18:08:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696442932; bh=7KinbA8DNblA+Km2f8glGeQw5rEldbniDtB58mio/Fw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=rHzpZAiVZd7ZFkiW/MGVBek96RFTIJjcohB0e/YOf0qtsOfUMAWU2MGGzR58wiowk D/P/URX2DhFNOVR9vJ/iYgXQQu+nnZ5LcLPjq6DjmC5SGUzxYiaHXdCc5gSw1Ymo4S usX+ofMOub/zY945XGGYVRJBlqabJwqtchOEsNd+6vjIXbgMUhT/H/VTfV29ZP1zYn 7t3V1E3MqfJZe+cr64wLZXz+p5xjo/GJfotavtLabkH2PDWZF3sC02RK5Qfd6RcDrF eo0r5avug/98hGKx9/kkETVhBcDLVQZFFIQdQ3mIL7Q0qfasJBbkh90UaCgQI+7fwV RlRsShJqz9k3w== Date: Wed, 4 Oct 2023 11:08:50 -0700 From: Jakub Kicinski To: Alexander Lobakin Message-ID: <20231004110850.5501cd52@kernel.org> In-Reply-To: <8e9d830b-556b-b8e6-45df-0bf7971b4237@intel.com> References: <20230927075124.23941-1-larysa.zaremba@intel.com> <20230927075124.23941-10-larysa.zaremba@intel.com> <20231003053519.74ae8938@kernel.org> <8e9d830b-556b-b8e6-45df-0bf7971b4237@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-ID-Hash: I7WHO2JCWLYAPSM44EKKCVGVCNEDXEY3 X-Message-ID-Hash: I7WHO2JCWLYAPSM44EKKCVGVCNEDXEY3 X-MailFrom: kuba@kernel.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: Larysa Zaremba , bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, David Ahern , Willem de Bruijn , Jesper Dangaard Brouer , Anatoly Burakov , Alexander Lobakin , Magnus Karlsson , Maryam Tahhan , xdp-hints@xdp-project.net, netdev@vger.kernel.org, Willem de Bruijn , Alexei Starovoitov , Simon Horman , Tariq Toukan , Saeed Mahameed , Maciej Fijalkowski X-Mailman-Version: 3.3.8 Precedence: list Subject: [xdp-hints] Re: [RFC bpf-next v2 09/24] xdp: Add VLAN tag hint List-Id: XDP hardware hints design discussion Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Tue, 3 Oct 2023 15:09:39 +0200 Alexander Lobakin wrote: > > Sorry for a random chime-in but was there any discussion about > > the validity of VLAN stripping as an offload? > > > > I always thought this is a legacy "Windows" thing which allowed > > Windows drivers to operate on VLAN-tagged networks even before > > the OS itself understood VLANs... Do people actually care about > > having it enabled? > > On MIPS routers, I actually have some perf gains from having it enabled. > So they do, I'd say. Mediatek even has DSA tag stripping. Both save you > some skb->data push-pulls, csum corrections when CHECKSUM_COMPLETE, skb > unsharing in some cases, reduce L3/L4 headers cacheline spanning etc. No unsharing - you can still strip it in the driver. Do you really think that for XDP kfunc call will be cheaper?