From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-il1-x141.google.com (mail-il1-x141.google.com [IPv6:2607:f8b0:4864:20::141]) (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 DFC363B29E for ; Fri, 8 May 2020 11:12:11 -0400 (EDT) Received: by mail-il1-x141.google.com with SMTP id e8so1703719ilm.7 for ; Fri, 08 May 2020 08:12:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=AobdXLN9zo4GvdH/dkLVlkbjw47518N9zGBvwxcHFow=; b=eXARyRSqq0GkRNXom+W/wpQNjKSK6/WXsAGAEcrauR3QhpCWmWsThvolxaO/U3WvRd bYFCek+pW5giVM/3Pf0hmTHuoAz5PyqM8nOzrrYTOVmaOxxlUGaKPjMtvL5OkNjTcW63 QfO4+qK5K8JwqUKOFiIleD30kFU3gQc0ajAlgM5/EPXCBYQ0ACda1nLFBpgSIcGV9TNb 27UTst73EsH+RouUb8B6q5lS+hXrnLRohVDtiVInK7M7j48Ax8aWuRv1SsHDj5HMIxl9 R50OAuLV1DwUf0E6YM59kLrL0ig5qAGI6rptjz5xBx4vMNBpC66BFJeQTCj7cMoBlCve gjFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=AobdXLN9zo4GvdH/dkLVlkbjw47518N9zGBvwxcHFow=; b=C1my2jIcD7W6rgcofchdI5NKJTaj9UtK4vrraeYMnSpQldVWa0e1uI+NyiSsskqzgi phAAOTD6/zADh4lZa1PgMNpdV4slpMN8iLDid91buZqwMiI2N0jVdOh3IyE9iaSXyzZp Yf9r9Wnd5oq3b8LTMG7yjp34IQLZvHxL84glUWEpl0tzsR0ywUbA7hHa0DNLF4nAjaqL Z1U8JVKocspvsRNBinsJQxPXk/iyOc7uEueV0drbMsWbrzVpVToOReQDyCVOFNd8Su8W rSczX4fkb4sFu720DkyGOjZ3XGHyfLDz0PgILDEWlgC52BfdaDvvLQYPuXq2kGaRe0g8 6IEQ== X-Gm-Message-State: AGi0PuYP76znvHu56MWByX4azlO8m4SF7nMjjVrCPFx4JCwWvrXbw+yf E/lY2EA/pAfnSxb9tDKymRGGJ4TQbgpnf8vjgTw= X-Google-Smtp-Source: APiQypLyDzdaOE+N9t4mYt5QKRTwceT35hIOla6PLC0FucOsFqwfD1BriIFrW8x16JzaugjyMZgPiOugRyOk+RtrCmE= X-Received: by 2002:a92:77c4:: with SMTP id s187mr3467430ilc.45.1588950731394; Fri, 08 May 2020 08:12:11 -0700 (PDT) MIME-Version: 1.0 References: <87wo5okhbo.fsf@toke.dk> <875zd6h3bu.fsf@toke.dk> In-Reply-To: <875zd6h3bu.fsf@toke.dk> From: Dave Taht Date: Fri, 8 May 2020 08:11:59 -0700 Message-ID: To: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= Cc: Avakash bhat , Vybhav Pai , Shrinidhi Varna , Cake List , "Mohit P. Tahiliani" , Deepak K Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Cake] Query on ACK X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 08 May 2020 15:12:12 -0000 On Fri, May 8, 2020 at 8:08 AM Toke H=C3=B8iland-J=C3=B8rgensen wrote: > > Dave Taht writes: > > > On Thu, May 7, 2020 at 11:36 PM Avakash bhat wro= te: > >> > >> Ok thanks so much for the clarifications. > >> That cleared it up quite a bit. > > > > I note that there was something really subtle that could have been > > done to improve cake's ack handling, and for all I know > > it actually happened in the final codebase. > > > > so, please, go forth and duplicate the existing implementation, and > > ignore me, cause looking at this hairy code gives me a > > headache. > > > > anyway, to try and describe what I thought I saw an interaction with > > the scheduler back in the day. > > > > The ack-filter runs, deleting all but one packet from the ack queue, > > and delivers that. > > the scheduler runs, serves a bunch of other flows, then returns to the > > ack queue, which has accumulated a couple more packets, > > the ack-filter runs, deleting all but one packet from the ack queue, > > and delivers that, but doesn't exhaust its qauntum > > The ACK filter runs on enqueue, so if a queue has only ACKs in it, it > will never accumulate anything in the first place... but the side effect is that on dequeue, it flips it into the fast queue drr rotation, not the slow, so it can't accumulate as many acks before delivering the one it has left. Or so I thought, way back when.... > > -Toke > --=20 Make Music, Not War Dave T=C3=A4ht CTO, TekLibre, LLC http://www.teklibre.com Tel: 1-831-435-0729