From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0DF61C77B70 for ; Mon, 17 Apr 2023 12:41:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229929AbjDQMl1 (ORCPT ); Mon, 17 Apr 2023 08:41:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231235AbjDQMlE (ORCPT ); Mon, 17 Apr 2023 08:41:04 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D7F740C8 for ; Mon, 17 Apr 2023 05:40:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681735216; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=d8R/DyfPuxRJq8lFo64wBLNVpfrgX/DMbIH8EiFz9DI=; b=KMGsqX9C3C4HUW/gl2Fq4iAo2G4l49JJ9WT7jHHKPG7E8HRQDjjWLcrUEjB6L5nzjN9YPH XkxGfDeCLG7dq/1iLPA4c89nkybkC4uoS5m0aXHh6d3zkSTtV8klR5zWd/iODG4UZlpNBF i0BgFqnPHTvja/XOsPaL2aoi4n0EU6s= Received: from mail-ej1-f69.google.com (mail-ej1-f69.google.com [209.85.218.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-537-32kMjgjQNDKsRmYlM6Pozw-1; Mon, 17 Apr 2023 08:40:07 -0400 X-MC-Unique: 32kMjgjQNDKsRmYlM6Pozw-1 Received: by mail-ej1-f69.google.com with SMTP id tq24-20020a170907c51800b0093138c6f2f8so8743370ejc.22 for ; Mon, 17 Apr 2023 05:40:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681735206; x=1684327206; h=content-transfer-encoding:mime-version:message-id:date:references :in-reply-to:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=d8R/DyfPuxRJq8lFo64wBLNVpfrgX/DMbIH8EiFz9DI=; b=heykqJIJWxbf3EwzqumdU64PiwoMKgSCcyrkid37sBPPND3anLi/V/Oxff4sdlLg8v lSXdVaSaK4VDofFT33yMDAiXa2Z5KX5LkhoIVuelsuwuQDJljrut/yE3Wrpwgqa9+uLw GSdXP1g/R5fe8TSr6zWLG0VzHRMyAi0eGsXrqRzfZZy2NP094atRtaAxllJ6VPxNCsg9 bpt83usPQ8hL3opcfPAMFC3hpzmuc41dNwbXtbxdZCA0tUI4ReVNkV90YDYJ7u8mU+Fn wJtU3OxwQfd+oDEyUz2hPepL8Ic/TcEWR04WT2RxGrEEUVXE4QGYj+ylBjhqMMHpaccC CQMg== X-Gm-Message-State: AAQBX9dc9N72S3nd4OeC0Bues9YQZG4U4byIpgqxBdK6WfaKRohx+tMC xvR2ArIjIzbeoF6glgt6/CnE8YLnsnyEz+v8fWHiWcmnp70lEnRRHNPCFSjFtQ7wg4dQRB/Tc3j FlPeI5gleQ0KB X-Received: by 2002:a17:906:ae56:b0:932:1af9:7386 with SMTP id lf22-20020a170906ae5600b009321af97386mr7169620ejb.27.1681735206437; Mon, 17 Apr 2023 05:40:06 -0700 (PDT) X-Google-Smtp-Source: AKy350aW/kxO/780wfJlvoA8/SxGVLczSeSpBXtQ9jUSEU7Eij2vduEeVE6+vnyBY1Qt/CkYdfKc2w== X-Received: by 2002:a17:906:ae56:b0:932:1af9:7386 with SMTP id lf22-20020a170906ae5600b009321af97386mr7169594ejb.27.1681735206008; Mon, 17 Apr 2023 05:40:06 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk ([45.145.92.2]) by smtp.gmail.com with ESMTPSA id 14-20020a17090601ce00b0094a671c2298sm1119966ejj.62.2023.04.17.05.40.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Apr 2023 05:40:05 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id B7E40AA8452; Mon, 17 Apr 2023 14:40:04 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Magnus Karlsson Cc: Kal Cutter Conley , Maciej Fijalkowski , =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= , Magnus Karlsson , Jonathan Lemon , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jonathan Corbet , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH bpf-next v3 1/3] xsk: Support UMEM chunk_size > PAGE_SIZE In-Reply-To: References: <20230406130205.49996-1-kal.conley@dectris.com> <20230406130205.49996-2-kal.conley@dectris.com> <87sfdckgaa.fsf@toke.dk> <875ya12phx.fsf@toke.dk> <87ile011kz.fsf@toke.dk> <87o7nrzeww.fsf@toke.dk> X-Clacks-Overhead: GNU Terry Pratchett Date: Mon, 17 Apr 2023 14:40:04 +0200 Message-ID: <87o7nmwul7.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Magnus Karlsson writes: > On Thu, 13 Apr 2023 at 22:52, Toke H=C3=B8iland-J=C3=B8rgensen wrote: >> >> Kal Cutter Conley writes: >> >> >> Well, you mentioned yourself that: >> >> >> >> > The disadvantage of this patchset is requiring the user to allocate >> >> > HugeTLB pages which is an extra complication. >> > >> > It's a small extra complication *for the user*. However, users that >> > need this feature are willing to allocate hugepages. We are one such >> > user. For us, having to deal with packets split into disjoint buffers >> > (from the XDP multi-buffer paradigm) is a significantly more annoying >> > complication than allocating hugepages (particularly on the RX side). >> >> "More annoying" is not a great argument, though. You're basically saying >> "please complicate your code so I don't have to complicate mine". And >> since kernel API is essentially frozen forever, adding more of them >> carries a pretty high cost, which is why kernel developers tend not to >> be easily swayed by convenience arguments (if all you want is a more >> convenient API, just build one on top of the kernel primitives and wrap >> it into a library). >> >> So you'll need to come up with either (1) a use case that you *can't* >> solve without this new API (with specifics as to why that is the case), >> or (2) a compelling performance benchmark showing the complexity is >> worth it. Magnus indicated he would be able to produce the latter, in >> which case I'm happy to be persuaded by the numbers. > > We will measure it and get back to you. Would be good with some > numbers. Sounds good, thanks! :) -Toke