From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-x232.google.com (mail-ob0-x232.google.com [IPv6:2607:f8b0:4003:c01::232]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id A872D21F2A2 for ; Tue, 16 Jun 2015 10:22:31 -0700 (PDT) Received: by obbsn1 with SMTP id sn1so16175132obb.1 for ; Tue, 16 Jun 2015 10:22:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=+iCHuLMy1gkriu0j/G3JYWYqznjrIudZ5ISwuPu5bxE=; b=cZ59M4ej4ho02wU5hssiHx9oyvvAkqpnydCyj1BqBh93PU4xS2J6VhZethYr70LRhM 1MRbzmbg0el8KH+L+fdQs/iEH/G+VirM5361xbQ3il9OLvuNgARPZ4Rj82GhVWYRqjHW w5hkd4aEj4KJTjIFp7lNWK4AwxUDAJWopaV4CZ5kt+cGwRlnxyWP8t2bQnPAzqk8wcW7 LYfmoYTcGNwkjWfkJJaQhkJYbwfMil2J6NsISHCvTQ3omqx/5Lso8NtB1U0RSYydyncN pTh2zBWjUpNtUuAANuN8j188AaOhxyN91wiBFprhAzSocvPr0MJgoXXCIEJX2tqd3MQe ygpg== MIME-Version: 1.0 X-Received: by 10.202.91.212 with SMTP id p203mr1073886oib.108.1434475350495; Tue, 16 Jun 2015 10:22:30 -0700 (PDT) Received: by 10.202.105.129 with HTTP; Tue, 16 Jun 2015 10:22:30 -0700 (PDT) In-Reply-To: <1A30B531-745C-4323-9929-9EEBD94D775F@gmail.com> References: <20150616161807.GA31289@sesse.net> <1A30B531-745C-4323-9929-9EEBD94D775F@gmail.com> Date: Tue, 16 Jun 2015 10:22:30 -0700 Message-ID: From: Dave Taht To: Jonathan Morton Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: bloat Subject: Re: [Bloat] using tcp_notsent_lowat in various apps? X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 16 Jun 2015 17:23:00 -0000 On Tue, Jun 16, 2015 at 9:33 AM, Jonathan Morton wr= ote: > >> On 16 Jun, 2015, at 19:18, Steinar H. Gunderson = wrote: >> >> On Tue, Jun 16, 2015 at 09:11:08AM -0700, Dave Taht wrote: >>> I just tossed off a quick patch for rsync, not that I have a clue as >>> to whether it would make any difference there. >> >> For bulk applications (like rsync), how would this make sense at all? >> I thought the entire point of this option was if you knew what data to s= end >> now, but that you might want to change your mind later if it takes some = time >> to send it. The latter doesn't apply to rsync. > > Actually, it does. Rsync is designed to be used to update an existing se= t of files, so the protocol interleaves control and data information asynch= ronously. > > More generally, I think it=E2=80=99s worth setting LOWAT on *any* applica= tion that uses select() or poll() with a readable and writable socket popul= ation simultaneously. Take samba as another potential example. I commonly see this increasing the SO_SNDBUF to a given value, but I am not sure if this is the right thing anymore. As samba is commonly used for filesharing (and things that take locks and do database-y stuff), improving interactivity might be a big win. Seeing the 50%! decrease in kernel memory on the original tests of TCP_SENT_LOWAT is very exciting in the context of those running samba on tiny tiny nas devices common in my world. And seeing apple enable it universally points to perhaps exploring the effects of just enabling it universally in linux (or in certain kinds of linux-based devices) at a "reasonable" value, for whatever value of reasonable exists. > - Jonathan Morton > > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat --=20 Dave T=C3=A4ht What will it take to vastly improve wifi for everyone? https://plus.google.com/u/0/explore/makewififast