From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by mail.toke.dk (Postfix) with ESMTPS id 481D6A41EB3 for ; Fri, 1 Dec 2023 16:39:42 +0100 (CET) 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=TRASJF6O Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by ams.source.kernel.org (Postfix) with ESMTP id C280DB82252; Fri, 1 Dec 2023 15:39:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6EBDDC433C7; Fri, 1 Dec 2023 15:39:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701445181; bh=V7WtW43roNI+kWQ1jgxoaFh9ZbnjwKeONNImrea0QOQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=TRASJF6OIlc3u7XXuhbDaK4viFQJH7E7P4b0J4LqnZBm3T4XlnR3wBJcRPM9GJJO4 4Y3WNVYM4egNGn7EKS+XOf7HsyIWWI1Ehnm+UycZlQSrC7GkVbPj/7oh4rYBe9Ht/3 Q8rfJDaPym3mbS1oRuUcd7Vy4vu8MUT7Jlq0QsMl1UPCi5URZ2uu+0dCnh7/NJHdvr AOgvp6+9g5MBccZC9x5e2TXU8Eg2bC9bCY7IiiWlMjj1jU3MkU2p5RjuMLWiXpjfxN KoK0WQEMGg98VWuozPV8zRgNgzyxLI3luIXEVYj89SJnBDR6Vm0nnbrxcaIOf+rl7s FVxTlyu/GUKTA== Message-ID: <179a4581-f7df-4eb1-ab67-8d65f856a2fe@kernel.org> Date: Fri, 1 Dec 2023 16:39:32 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: Willem de Bruijn , "Song, Yoong Siang" , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jonathan Corbet , Bjorn Topel , "Karlsson, Magnus" , "Fijalkowski, Maciej" , 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 , Andre Fredette References: <20231201062421.1074768-1-yoong.siang.song@intel.com> <6569f71bad00d_138af5294d@willemb.c.googlers.com.notmuch> From: Jesper Dangaard Brouer In-Reply-To: <6569f71bad00d_138af5294d@willemb.c.googlers.com.notmuch> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Message-ID-Hash: ON24HMTMOFWLI5AQ4F3UPGKLQMKBDXSB X-Message-ID-Hash: ON24HMTMOFWLI5AQ4F3UPGKLQMKBDXSB X-MailFrom: hawk@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: "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" X-Mailman-Version: 3.3.8 Precedence: list Subject: [xdp-hints] Re: [PATCH bpf-next v2 0/3] xsk: TX metadata txtime support List-Id: XDP hardware hints design discussion Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 12/1/23 16:09, Willem de Bruijn wrote: > Song, Yoong Siang wrote: >> On Friday, December 1, 2023 6:46 PM, Jesper Dangaard Brouer wrote: >>> On 12/1/23 07:24, Song Yoong Siang wrote: >>>> This series expands XDP TX metadata framework to include ETF HW offload. >>>> >>>> Changes since v1: >>>> - rename Time-Based Scheduling (TBS) to Earliest TxTime First (ETF) >>>> - rename launch-time to txtime >>>> >>> >>> I strongly disagree with this renaming (sorry to disagree with Willem). >>> >>> The i210 and i225 chips call this LaunchTime in their programmers >>> datasheets, and even in the driver code[1]. >>> >>> Using this "txtime" name in the code is also confusing, because how can >>> people reading the code know the difference between: >>> - tmo_request_timestamp and tmo_request_txtime >>> >> >> Hi Jesper and Willem, >> >> How about using "launch_time" for the flag/variable and >> "Earliest TxTime First" for the description/comments? > I don't follow why you are calling the feature: - "Earliest TxTime First" (ETF). - AFAIK this just reference an qdisc name (that most don't know exists) > I don't particularly care which term we use, as long as we're > consistent. Especially, don't keep introducing new synonyms. > > The fact that one happens to be one vendor's marketing term does not > make it preferable, IMHO. On the contrary. > These kind of hardware features are defined as part of Time Sensitive Networking (TSN). I believe these TSN features are defined as part of IEEE 802.1Qbv (2015) and according to Wikipedia[2] incorporated into IEEE 802.1Q. [2] https://en.wikipedia.org/wiki/Time-Sensitive_Networking > SO_TXTIME is in the ABI, and EDT has been used publicly in kernel > patches and conference talks, e.g., Van Jacobson's Netdev 0x12 > keynote. Those are vendor agnostic commonly used terms. > I agree that EDT (Earliest Departure Time) have become a thing and term in our community. We could associate this feature with this. I do fear what hardware behavior will be it if I e.g. ask it to send a packet 2 sec in the future on i225 which max support 1 sec. Will hardware send it at 1 sec? Because then I'm violating the *Earliest* Departure Time. > But as long as Launch Time is not an Intel only trademark, fine to > select that. The IEEE 802.1Qbv is sometimes called Time-Aware Shaper (TAS), but I don't like to for us to name this after this. This features is simply taking advantage of exposing one of the hardware building blocks (controlling/setting packet "launch time") that can be used for implementing a TAS. I like the name "launch time" because it doesn't get easily confused with other timestamps, and intuitively describes packet will be send at a specific time (likely in future). --Jesper