From owner-freebsd-net@FreeBSD.ORG Tue Mar 25 02:00:59 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 1E3D1684; Tue, 25 Mar 2014 02:00:59 +0000 (UTC) Received: from esa-annu.net.uoguelph.ca (esa-annu.mail.uoguelph.ca [131.104.91.36]) by mx1.freebsd.org (Postfix) with ESMTP id A66E7759; Tue, 25 Mar 2014 02:00:58 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AqAEAHHiMFODaFve/2dsb2JhbABZhBiDB79fgTh0giUBAQEEI1YMDxoCDRkCWQaIDKxEok4XgSmMeSQ0B4JvgUkElFwHlhiDSSGBLEI X-IronPort-AV: E=Sophos;i="4.97,724,1389762000"; d="scan'208";a="108551171" Received: from muskoka.cs.uoguelph.ca (HELO zcs3.mail.uoguelph.ca) ([131.104.91.222]) by esa-annu.net.uoguelph.ca with ESMTP; 24 Mar 2014 22:00:57 -0400 Received: from zcs3.mail.uoguelph.ca (localhost.localdomain [127.0.0.1]) by zcs3.mail.uoguelph.ca (Postfix) with ESMTP id A45A7B3F0B; Mon, 24 Mar 2014 22:00:57 -0400 (EDT) Date: Mon, 24 Mar 2014 22:00:57 -0400 (EDT) From: Rick Macklem To: Julian Elischer Message-ID: <510031798.2531808.1395712857661.JavaMail.root@uoguelph.ca> In-Reply-To: <0BC10908-2081-45AC-A1C8-14220D81EC0A@hostpoint.ch> Subject: Re: 9.2 ixgbe tx queue hang MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [172.17.91.209] X-Mailer: Zimbra 7.2.1_GA_2790 (ZimbraWebClient - FF3.0 (Win)/7.2.1_GA_2790) Cc: FreeBSD Net , Garrett Wollman , Jack Vogel , Christopher Forgeron 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, 25 Mar 2014 02:00:59 -0000 Julian Elischer wrote: ----- Original Message ----- > I wrote (and snipped): >> Other drivers (and ixgbe for the 82598 chip) can handle a packet that >> is in more than 32 mbufs. (I think the 82598 handles 100, grep for >> SCATTER >> in *.h in sys/dev/ixgbe.) >> > > the Xen backend can not handle mor ethan 32 segments in some versions > of Xen. Btw, I just did a quick find/grep (so I may have missed some), but here is the list of net devices that appear to support TSO, but limited to 32 transmit segments for at least some supported chips: jme, fxp, age, sge, msk, als, ale, ixgbe/ix, nfe, e1000/em, re Also, several of these call m_collapse() instead of m_defrag() when the run into a transmit mbuf list with > 32 elements. m_collapse() - Isn't likely to squeeze the 35 mbuf 64Kbyte NFS I/O message into 32 mbufs, so I don't think these ones will work at all for NFS with default 64K I/O size and TSO enabled. rick