From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 5A767A0032; Sat, 4 Jun 2022 11:33:36 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 3A7484021E; Sat, 4 Jun 2022 11:33:36 +0200 (CEST) Received: from mail-qt1-f172.google.com (mail-qt1-f172.google.com [209.85.160.172]) by mails.dpdk.org (Postfix) with ESMTP id AA99B40041; Sat, 4 Jun 2022 11:33:34 +0200 (CEST) Received: by mail-qt1-f172.google.com with SMTP id 2so7344738qtw.0; Sat, 04 Jun 2022 02:33:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=Vgb2Y9oAFiaWdNDDA11aksI5LcHAnmxyfEQhm99JC2Y=; b=CmUOP7MOGqGVdswwpUyunFRwSnp1I1HnOtGaGOb1QsnapkmCkpz/iOv59tCsuLAm4R DNkQriGw3sVdGB+buZEZx6bUVPmIYR7/Q63UceHjcaPJUZ00Y94fymJzEgONtNB/IMIv MJHhv30XJktTcb9CfM4rjwNxMy2ystx9QKp7V+D0uKvy5tgqhb5mRYeA4voODHvj1M9f 3ze8qvdzCT8eVY4yuWu0RxmNwHkTQqoJ7UDE9pmlV36rhpCbfjHMOGFxb9/TFzHObEnZ domjHktN1SxaYwbNWoumpmROXcEcrIAd6ulBnZIbT0hwrcXhj734wMRdDCi0056Fm5ke a28w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=Vgb2Y9oAFiaWdNDDA11aksI5LcHAnmxyfEQhm99JC2Y=; b=i5aEoODV1o12vwhYBtYiJdVu8+2iBPe1zPB79MXDCce1ZZ8q7lwLq0cyPRETJIydER rN9S/IQNqKE4ENO5pyUCJDKg6iBp5aI2p74ylUK3/l/At+EI2BTrvFzVnLq0Sm7bPfoZ qVXKBR5SN+QqiRKrEdm34cqexWiEwCz9tb+1gXdOgQziTe8SekSspd7m97QShWClREsJ D5nADtw3GAk2YGaIiSQ7Vy1BmT3Nvi7QmRpCx/MeOFKG5ulzLyZJOEqDYMTikKsW1Bzl TEAOmb3EIt7zEhSCXEyVVjeaOQYhUr8LXdZinZgHSISJmJyW3kxD44ohLXZndnDF+pzG D7qw== X-Gm-Message-State: AOAM530j7XsjR0VY36uGbFvKoSfRm6jUn2AlKfbmvhTRzxsoHXYEyYAy b1wVztWiY+EQbxCq/7iK0rAXW4Bcn1vY1tAiE31mYAmv X-Google-Smtp-Source: ABdhPJxoqRfLcfbc+9jz1U6B2lLUG68szE1UAGUUwotknqnyKdty+erpg4vWNJ4g25ANng6hJeuZlPT3E8cEVCwze94= X-Received: by 2002:a05:622a:8c:b0:302:b38e:53e2 with SMTP id o12-20020a05622a008c00b00302b38e53e2mr11194926qtw.410.1654335214022; Sat, 04 Jun 2022 02:33:34 -0700 (PDT) MIME-Version: 1.0 References: <98CBD80474FA8B44BF855DF32C47DC35D870EB@smartserver.smartshare.dk> In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35D870EB@smartserver.smartshare.dk> From: Jerin Jacob Date: Sat, 4 Jun 2022 15:03:08 +0530 Message-ID: Subject: Re: Optimizations are not features To: =?UTF-8?Q?Morten_Br=C3=B8rup?= Cc: dpdk-dev , techboard@dpdk.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Sat, Jun 4, 2022 at 2:39 PM Morten Br=C3=B8rup wrote: > > I would like the DPDK community to change its view on compile time option= s. Here is why: > > > > Application specific performance micro-optimizations like =E2=80=9Cfast m= buf free=E2=80=9D and =E2=80=9Cmbuf direct re-arm=E2=80=9D are being added = to DPDK and presented as features. > > > > They are not features, but optimizations, and I don=E2=80=99t understand = the need for them to be available at run-time! > > > > Instead of adding a bunch of exotic exceptions to the fast path of the PM= Ds, they should be compile time options. This will improve performance by a= voiding branches in the fast path, both for the applications using them, an= d for generic applications (where the exotic code is omitted). Agree. I think, keeping the best of both worlds would be -Enable the feature/optimization as runtime -Have a compile-time option to disable the feature/optimization as an overr= ide. > > > > Please note that I am only talking about the performance optimizations th= at are limited to application specific use cases. I think it makes sense to= require that performance optimizing an application also requires recompili= ng the performance critical libraries used by it. > > > > Allowing compile time options for application specific performance optimi= zations in DPDK would also open a path for other optimizations, which can o= nly be achieved at compile time, such as =E2=80=9Cno fragmented packets=E2= =80=9D, =E2=80=9Cno attached mbufs=E2=80=9D and =E2=80=9Csingle mbuf pool= =E2=80=9D. And even more exotic optimizations, such as the =E2=80=9Cindexed= mempool cache=E2=80=9D, which was rejected due to ABI violations =E2=80=93= they could be marked as =E2=80=9Crisky and untested=E2=80=9D or similar, b= ut still be part of the DPDK main repository. > > > > > > Med venlig hilsen / Kind regards, > > -Morten Br=C3=B8rup > >