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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D630C433F5 for ; Fri, 24 Sep 2021 23:31:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 074FB6103C for ; Fri, 24 Sep 2021 23:31:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237084AbhIXXcm (ORCPT ); Fri, 24 Sep 2021 19:32:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49872 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231238AbhIXXcl (ORCPT ); Fri, 24 Sep 2021 19:32:41 -0400 Received: from mail-wr1-x435.google.com (mail-wr1-x435.google.com [IPv6:2a00:1450:4864:20::435]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7ECB9C061571 for ; Fri, 24 Sep 2021 16:31:07 -0700 (PDT) Received: by mail-wr1-x435.google.com with SMTP id c21so2291530wrb.13 for ; Fri, 24 Sep 2021 16:31:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=GqZeA34g+PTtS9vxOWyDlA/b9i9OPS+4sVJlXqOJs9A=; b=C6ThtuoBmix6FYu83kbezzPSbfwJ28lbagMxmRVlfziBKJn1iYK0NQNSitYWfv7mlC lGHL46fFshZgrbpNOFt3w2dl1kIAxO8uSXZmAGUUPIDlQCg+cKLyd2RHfl3EjHQr5l/+ FG2iqtc5epcU9ymLFf/mvoCGMwdg0esMPUQZTX9dFXSQv0jtfGe/TnOiuQffN5Z04DkM 7N5PD5iacdunFYG4QPp122xsb0+bBmdAcGb3yqWMlYozMrXj/wx7Revb9hOeE5lVKZPb o8Czla5JiXvF+eLOqypYAVuUT+T8h6WrMB7KKfcz4bHiGMOlHHUT/lnFykRdqNG/OfHA n0OQ== 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; bh=GqZeA34g+PTtS9vxOWyDlA/b9i9OPS+4sVJlXqOJs9A=; b=x/lsiNKBX5UNkRA33t+wok3THFZgMOE9dBAYVDbwSVkg+6aMkL00LU5lKAuYlPT/I0 FufdmBBNzXsVPvnePaMNOUrTxX3QUVca+ptuB3PnW+8l2pGqWT0/CkFBy3oi3XyDM+dU TG7mgpBa7V2OfmIzROPSJoK9s+bregqhCiUFqEC4E81hzVoP5dzs2ZwMZSYTJbCdTFlt LKMjG7iKeenc0v4v9qT+9QnrlVtq3H+CfbGCmdQtgDsdf3n2mJN1epk2FzjEMZNXDlvB jJ0scIEUbBmd4+HVzNPz2FR4HOfolr9cvP3KVF5jI9POr0fbzsAtiTtc62cPG3WNCRSi FTGg== X-Gm-Message-State: AOAM532atuF8C+cETITcPlrTTF0kGBs45mhQpQ/ViPS/wkloNEoHckTm sOhKxaC83SWldZJGxua4J4Qj7tgHFcf+iPsE2/hm6Q== X-Google-Smtp-Source: ABdhPJx8LIDoeKjlWKDfbaescxUb80+TVMp7FQQ2uFsOVoxrNgE4yc9Uy35zw5qUCRZ7CvR9zxAMTPbHGnzU1cux7pc= X-Received: by 2002:a7b:cd0d:: with SMTP id f13mr4431413wmj.183.1632526265933; Fri, 24 Sep 2021 16:31:05 -0700 (PDT) MIME-Version: 1.0 References: <20210923211706.2553282-1-luke.w.hsiao@gmail.com> <20210924132005.264e4e2d@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210924132005.264e4e2d@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> From: Yuchung Cheng Date: Fri, 24 Sep 2021 16:30:28 -0700 Message-ID: Subject: Re: [PATCH net-next] tcp: tracking packets with CE marks in BW rate sample To: Jakub Kicinski Cc: Luke Hsiao , David Miller , netdev@vger.kernel.org, Lawrence Brakmo , Neal Cardwell , Eric Dumazet , Luke Hsiao Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Sep 24, 2021 at 1:20 PM Jakub Kicinski wrote: > > On Thu, 23 Sep 2021 21:17:07 +0000 Luke Hsiao wrote: > > From: Yuchung Cheng > > > > In order to track CE marks per rate sample (one round trip), TCP needs a > > per-skb header field to record the tp->delivered_ce count when the skb > > was sent. To make space, we replace the "last_in_flight" field which is > > used exclusively for NV congestion control. The stat needed by NV can be > > alternatively approximated by existing stats tcp_sock delivered and > > mss_cache. > > > > This patch counts the number of packets delivered which have CE marks in > > the rate sample, using similar approach of delivery accounting. > > Is this expected to be used from BPF CC? I don't see a user.. Great question. Yes the commit message could be more clear that this intends for both ebpf-CC or other third party module that use ECN. For example bbr2 uses it heavily (bbr2 upstream WIP). This feature is useful for congestion control research which many use ECN as core signals now.