From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-x229.google.com (mail-wi0-x229.google.com [IPv6:2a00:1450:400c:c05::229]) (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 37F5521F1EC for ; Mon, 22 Jun 2015 00:02:15 -0700 (PDT) Received: by wiwl6 with SMTP id l6so27392455wiw.0 for ; Mon, 22 Jun 2015 00:02:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:subject:from:to:cc:date:in-reply-to:references :content-type:mime-version:content-transfer-encoding; bh=WSjiAf2RC709apkjMbET3Zz4QJZbx3RalcdAgB7bQpQ=; b=F9NzxLvy1rTbwLFNhvcBCiTfxzKgp0Q5EKwht9m3fo1WxXpZ2aiCWh13zZVp6mUtoi 1VPaHeEidX9XwsN78KomT2SxrVMDPe/NVx7Zj6WRhkw3d22WxQ8z47KjJtoks0Nzf1FW Bv0KSr67JN3sXAUMt2Tqz3DmJUR9c0D4M8rla7ipjFtRxu51CF1c4oS/e/BPvXQp4pXj ZXt+uL7ynXtdXRf3yREZxdf0O3F86rmuwEA1k+9fMFinChzqu23ZDivS09pUU6YgAlWm tQSprNjC5Dcq0tsmPNQDfkd5xOyIGna4quJEsjI8t3Sdf4d5+F3qJGQf4qIapWvyg9dG 4UOw== X-Received: by 10.180.86.198 with SMTP id r6mr29103068wiz.70.1434956533854; Mon, 22 Jun 2015 00:02:13 -0700 (PDT) Received: from [192.168.72.169] (catv-86-101-168-173.catv.broadband.hu. [86.101.168.173]) by mx.google.com with ESMTPSA id v3sm15697151wiz.14.2015.06.22.00.02.11 (version=TLSv1.2 cipher=AES128-GCM-SHA256 bits=128/128); Mon, 22 Jun 2015 00:02:12 -0700 (PDT) Message-ID: <1434956529.4110.1.camel@edumazet-glaptop2.roam.corp.google.com> From: Eric Dumazet To: Juliusz Chroboczek Date: Mon, 22 Jun 2015 09:02:09 +0200 In-Reply-To: <87y4jd3xwt.wl-jch@pps.univ-paris-diderot.fr> References: <87y4jgbejc.wl-jch@pps.univ-paris-diderot.fr> <6644BD81-1FFC-450C-89FD-91E138B7824A@gmail.com> <1434697811.31511.9.camel@edumazet-glaptop2.roam.corp.google.com> <87y4jd3xwt.wl-jch@pps.univ-paris-diderot.fr> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit 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: Mon, 22 Jun 2015 07:02:44 -0000 On Sun, 2015-06-21 at 17:04 +0200, Juliusz Chroboczek wrote: > Do you have any concrete examples where this has been found to yield > better results than what the kernel can do on its own? I'm probably > missing something, but my intuition is that conversational protocols > should be naturally self-pacing, while for streaming protocols the right > amount of buffering depends on the kernel latency, and hence should be > better done by the kernel itself. Unless you have thousands of tcp flows maybe, where (unswapable) kernel memory becomes a precious resource. Of course, if you have a few tcp sockets, just queuing 10 Mbytes per socket will be your best shot, in terms of cpu overhead (one schedule every 5 MBytes or so)