From owner-freebsd-bugs@FreeBSD.ORG Thu Sep 13 20:20:07 2007 Return-Path: Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A350D16A417 for ; Thu, 13 Sep 2007 20:20:07 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 4917B13C480 for ; Thu, 13 Sep 2007 20:20:07 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.14.1/8.14.1) with ESMTP id l8DKK7Dl017705 for ; Thu, 13 Sep 2007 20:20:07 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.1/8.14.1/Submit) id l8DKK7F6017704; Thu, 13 Sep 2007 20:20:07 GMT (envelope-from gnats) Resent-Date: Thu, 13 Sep 2007 20:20:07 GMT Resent-Message-Id: <200709132020.l8DKK7F6017704@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-bugs@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Kevin Oberman Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C6BFC16A419 for ; Thu, 13 Sep 2007 20:14:10 +0000 (UTC) (envelope-from SRS0=6448652a836d2ec8179b9be65cc60934e444ae3b=457=es.net=oberman@es.net) Received: from postal1.es.net (postal1.es.net [IPv6:2001:400:14:3::6]) by mx1.freebsd.org (Postfix) with ESMTP id 645A613C45D for ; Thu, 13 Sep 2007 20:14:10 +0000 (UTC) (envelope-from SRS0=6448652a836d2ec8179b9be65cc60934e444ae3b=457=es.net=oberman@es.net) Received: from ptavv.es.net (ptavv.es.net [198.128.4.29]) by postal1.es.net (Postal Node 1) with ESMTP (SSL) id SDB11903 for ; Thu, 13 Sep 2007 13:14:03 -0700 Received: by ptavv.es.net (Tachyon Server, from userid 9381) id 958D14500E; Thu, 13 Sep 2007 13:14:02 -0700 (PDT) Message-Id: <20070913201402.958D14500E@ptavv.es.net> Date: Thu, 13 Sep 2007 13:14:02 -0700 (PDT) From: Kevin Oberman To: FreeBSD-gnats-submit@FreeBSD.org X-Send-Pr-Version: 3.113 Cc: Subject: kern/116335: Excessive TCP window updates X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Kevin Oberman List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 13 Sep 2007 20:20:07 -0000 >Number: 116335 >Category: kern >Synopsis: Excessive TCP window updates >Confidential: no >Severity: serious >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Thu Sep 13 20:20:06 GMT 2007 >Closed-Date: >Last-Modified: >Originator: Kevin Oberman >Release: FreeBSD 6.2-STABLE i386 >Organization: ESnet--The Energy Sciences Network >Environment: System: FreeBSD ptavv.es.net 6.2-STABLE FreeBSD 6.2-STABLE #11: Thu Aug 16 17:18:58 PDT 2007 root@ptavv.es.net:/usr/obj/usr/src/sys/PTAVV i386 >Description: Testing over a trans-continental 10GE between two boxes with mxge cards, at a point about 2.5 seconds into the tansfer, the receive node starts updating the window size as fast as it can process the data. The result is that it is sending updates at intervals of between 0 and 4 microseconds. This can result in several hundred window updates between "real" packets and, I suspect, is causing performance problems. I see an old message at: http://lists.freebsd.org/pipermail/freebsd-net/2005-January/006141.html that may be the source of the problem, though I have not yet figured out exactly how this code works. >How-To-Repeat: Send a TCP stream between to hosts with a ~100 ms. RTT between them at speeds exceeding 3 Gbps. >Fix: Unknown. >Release-Note: >Audit-Trail: >Unformatted: