From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2402022333; Mon, 4 Dec 2023 10:36:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TYuJbBEO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B651CC433C7; Mon, 4 Dec 2023 10:36:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701686198; bh=+ErQN2WS12/khFYfpQDZFxvXogAuk59InCRmaNowfS4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=TYuJbBEOWc7KkHydu2jfldkno0up5yHsG0uUho4wBtYHENJrIhEzopw828B8nYR2y /Bq7E40/MYPd1WbSuMXOvrTR5LHNu4Nyf/Kw+gB/7gkQzftmk1CpVYV9eJwBzY35J7 xEUZGCUu5mNhYCftzglLku0Qv8rqkxUO3hFH3lqEzc07PY3VLfg/jHqko9fsaF3gZi n60G9Q65Bc1Acq6pmo9DI1XvzmOdhIgAhp4s7D3JCsTjOCRoMf5DFu4Adbt8rs1jkb JUYwE//FlD7965G/pbx4+GWSA9D9XyXOvGaEDUVAyM3lQkuP2ld5EEhAtkvcn/6u8N p2QNPiNTkbN1g== Message-ID: <43b01013-e78b-417e-b169-91909c7309b1@kernel.org> Date: Mon, 4 Dec 2023 11:36:30 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next v3 2/3] net: stmmac: add Launch Time support to XDP ZC Content-Language: en-US To: Song Yoong Siang , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jonathan Corbet , Bjorn Topel , Magnus Karlsson , Maciej Fijalkowski , Jonathan Lemon , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Stanislav Fomichev , Lorenzo Bianconi , Tariq Toukan , Willem de Bruijn , Maxime Coquelin , Andrii Nakryiko , Mykola Lysenko , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , Hao Luo , Jiri Olsa , Shuah Khan , Alexandre Torgue , Jose Abreu Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, bpf@vger.kernel.org, xdp-hints@xdp-project.net, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org References: <20231203165129.1740512-1-yoong.siang.song@intel.com> <20231203165129.1740512-3-yoong.siang.song@intel.com> From: Jesper Dangaard Brouer In-Reply-To: <20231203165129.1740512-3-yoong.siang.song@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 12/3/23 17:51, Song Yoong Siang wrote: > This patch enables Launch Time (Time-Based Scheduling) support to XDP zero > copy via XDP Tx metadata framework. > > Signed-off-by: Song Yoong Siang > --- > drivers/net/ethernet/stmicro/stmmac/stmmac.h | 2 ++ As requested before, I think we need to see another driver implementing this. I propose driver igc and chip i225. The interesting thing for me is to see how the LaunchTime max 1 second into the future[1] is handled code wise. One suggestion is to add a section to Documentation/networking/xsk-tx-metadata.rst per driver that mentions/documents these different hardware limitations. It is natural that different types of hardware have limitations. This is a close-to hardware-level abstraction/API, and IMHO as long as we document the limitations we can expose this API without too many limitations for more capable hardware. [1] https://github.com/xdp-project/xdp-project/blob/master/areas/tsn/code01_follow_qdisc_TSN_offload.org#setup-code-driver-igb This stmmac driver and Intel Tiger Lake CPU must also have some limit on how long into the future it will/can schedule packets? People from xdp-hints list must make their voice hear if they want i210 and igb driver support, because it have even-more hardware limitations, see [1] (E.g. only TX queue 0 and 1 supports LaunchTime). BUT I know some have this hardware in production and might be motivated to get a functioning driver with this feature? --Jesper