From owner-freebsd-net@FreeBSD.ORG Tue Mar 4 01:11:21 2014 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id E14319A7; Tue, 4 Mar 2014 01:11:21 +0000 (UTC) Received: from mail-qc0-x22f.google.com (mail-qc0-x22f.google.com [IPv6:2607:f8b0:400d:c01::22f]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 91220AF3; Tue, 4 Mar 2014 01:11:21 +0000 (UTC) Received: by mail-qc0-f175.google.com with SMTP id e16so4646174qcx.20 for ; Mon, 03 Mar 2014 17:11:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=0lxip/oEUNs/BjXAsRe6KF4nzvPM1g+d9xVRZDnNR4s=; b=ZxzXpigoiLRvq3IR8en2Pl23/fpG+FrkJCUwLD58uRb1bczoowkajsz3MCHbfep3cx 4F7zMvUYoVPmTtdZ8e2gT3tBphiqsKccWvPXmH0RJ9zPtmUFa81vqlKvREeUkkltBs1g BqW6do9g+QHWVbDGLFvxhWgPdXXa4RX/IVr+E1Fx9PYaZnHpmHgyglYmm7Os2eM1n1qB zpYCabPwI6IrmDNmiUHPLlR1+I9CxAcfMeobY6Q+nYIXOl3fmfGuOB/yulJNYPwLLI8I zVdhwIdC+T4vQUh/dLixnhsabSGfiBlo58YCrF2iRUbxyukbyoIo9VGlIHsxTyPjDro1 lYVw== MIME-Version: 1.0 X-Received: by 10.140.42.21 with SMTP id b21mr729774qga.87.1393895480733; Mon, 03 Mar 2014 17:11:20 -0800 (PST) Sender: adrian.chadd@gmail.com Received: by 10.224.16.10 with HTTP; Mon, 3 Mar 2014 17:11:20 -0800 (PST) In-Reply-To: <531499E2.2080109@FreeBSD.org> References: <531499E2.2080109@FreeBSD.org> Date: Mon, 3 Mar 2014 17:11:20 -0800 X-Google-Sender-Auth: iCAkPeBK4Uxr_0Ld5ud62HHmn9U Message-ID: Subject: Re: delayed_ack and Nagle's algorithm interaction From: Adrian Chadd To: Andriy Gapon Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-net X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 04 Mar 2014 01:11:21 -0000 What's the time interval between transmissions? Is it something dumb like bad timer behaviour? -a On 3 March 2014 07:04, Andriy Gapon wrote: > > Guys, > > my knowledge of TCP and our TCP/IP stack is quite basic. > It seems that we are running into a problem described here or something with > very similar symptoms: > http://www.stuartcheshire.org/papers/NagleDelayedAck/ > At least, if I either disable delayed_ack or use TCP_NODELAY option, then the > problem goes away. Otherwise, we see quite significant extra latencies. > Maybe an important detail: the problem is observed for communication between a > local host client and a server in a jail. So, all traffic is local (via > loopback interface). > > I have a pcap file that captures the problem. > Ideas, suggestion, etc are welcome. > Thanks! > -- > Andriy Gapon > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"