From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 7DF683CB37 for ; Fri, 27 Jan 2023 09:05:57 -0500 (EST) Received: by mail-wr1-x430.google.com with SMTP id h16so5037921wrz.12 for ; Fri, 27 Jan 2023 06:05:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=3iUweZk7c21vVazCBJSHKRnZiMX0BjYlMu49BpzP05g=; b=SSGFKDhzYbkaHbCpTedQ/iOwuNhN70z/mVX3VtLyeevcUj1E1w3fAq+vC7Zrp6dLAR wU2BfGLMrTpVQcd7fqLH+E8voEwd7mczAnZvr0gdAzLDKvY5g5P+F20xf0qeLIZzWb7w eEpW6JzZiQqB3R866YXn05JiH82HEhWcqnhyJ+//o/7PqM+nZQhsfel3ntKogW1Blqfq F1Ld04naoOaJaJhWPgCX1BDajQLz6VmQz/IqQb1g0Bm5qtEFwrvHyOACiO+wOZEFZrA1 0Yj5SUyteeI5PCbbbksyWs5byg32d+xNnCv7CEe6wesP+5LK6l3friZofZ4SxZJca37I fbFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=3iUweZk7c21vVazCBJSHKRnZiMX0BjYlMu49BpzP05g=; b=JH51i+7wEnjrLgQHgCUAg8JjqcYrpCs3SF6KZjHiX7FKuR6obkkSeSIr6IyL75vxvk zxR54fRpuHY+1FU6duTkB4QUDsMuLBzuagmqZ0yk7Kl2QQZURseDu5GNZvLz2DzLgcKO vubgewsjLEK8z5Led0JedMHYgpdYSGM46vIpFL4ZZyg2PjMMoaCMKVapJNLK3hPR5YzW OQYK7RRpvNXJ7SErJNz9y0CTiWOn64DyIXx1doQ1TsVOT454BU90lDCo9bwVYRqeU0Ef SL0e6FhzzUywIJ8uAkwiCzDoF31zYr8PoQfR8CJo46apF9I0LEE6nyr67Fp18ntdZo6p Si4A== X-Gm-Message-State: AFqh2kohKxFPB8aV9ZFZX2skTsGd3YO2+13z/o0yUWPY0xd3MTc29Cnc PjEcZ3Q7AyzwUkv6OZJuXu71zsWhIkjpqCteRMACYoPo X-Google-Smtp-Source: AMrXdXuqk46UVOvX/26SUa8agqsSGN4g2tpsZyIN7dxykU3n/gA7K/g1RwIhmK6DGWDBbRXiCwPB8a2c/D6Fjjum0F0= X-Received: by 2002:adf:f8d1:0:b0:2be:1df4:5c64 with SMTP id f17-20020adff8d1000000b002be1df45c64mr1028080wrq.430.1674828355486; Fri, 27 Jan 2023 06:05:55 -0800 (PST) MIME-Version: 1.0 References: <20230124170346.316866-1-jhs@mojatatu.com> <20230126153022.23bea5f2@kernel.org> In-Reply-To: From: Dave Taht Date: Fri, 27 Jan 2023 06:05:44 -0800 Message-ID: To: libreqos Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: [LibreQoS] Fwd: [PATCH net-next RFC 00/20] Introducing P4TC X-BeenThere: libreqos@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Many ISPs need the kinds of quality shaping cake can do List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Jan 2023 14:05:57 -0000 ---------- Forwarded message --------- From: Jamal Hadi Salim Date: Fri, Jan 27, 2023 at 6:00 AM Subject: Re: [PATCH net-next RFC 00/20] Introducing P4TC To: Jakub Kicinski Cc: , , , , , , , , , , , , , , , , , , , On Thu, Jan 26, 2023 at 6:30 PM Jakub Kicinski wrote: > > On Tue, 24 Jan 2023 12:03:46 -0500 Jamal Hadi Salim wrote: > > There have been many discussions and meetings since about 2015 in regar= ds to > > P4 over TC and now that the market has chosen P4 as the datapath specif= ication > > lingua franca > > Which market? Network programmability involving hardware - where at minimal the specification of the datapath is in P4 and often the implementation is. For samples of specification using P4 (that are public) see for example MS Azure: https://github.com/sonic-net/DASH/tree/main/dash-pipeline If you are a vendor and want to sell a NIC in that space, the spec you get is in P4. Your underlying hardware doesnt have to be P4 native, but at minimal the abstraction (as we are trying to provide with P4TC) has to be able to consume the P4 specification. For implementations where P4 is in use, there are many - some public others not, sample space: https://cloud.google.com/blog/products/gcp/google-cloud-using-p4runtime-to-= build-smart-networks There are NICs and switches which are P4 native in the market. IOW, there is beacoup $ investment in this space that makes it worth pursuing. TC is the kernel offload mechanism that has gathered deployment experience over many years - hence P4TC. > Barely anyone understands the existing TC offloads. Hyperboles like these are never helpful in a discussion. TC offloads are deployed today, they work and many folks are actively working on them. Are there challenges? yes. For one (and this applies to all kernel offloads) the process gets in the way of exposing new features. So there are learnings that we try to resolve in P4TC. I'd be curious to hear about your suffering with TC offloads and see if we can take that experience and make things better. >We'd need strong, > and practical reasons to merge this. Speaking with my "have suffered > thru the TC offloads working for a vendor" hat on, not the "junior > maintainer" hat. P4TC is "standalone" in that it does not affect other TC consumers or any other subsystems on performance; it is also sufficiently isolated in that you can choose to compile it out altogether and more importantly it comes with committed support. And i should emphasize this discussion on getting P4 on TC has been going on for a few years in the community culminating with this. cheers, jamal --=20 This song goes out to all the folk that thought Stadia would work: https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-69813666656= 07352320-FXtz Dave T=C3=A4ht CEO, TekLibre, LLC