From owner-freebsd-net@FreeBSD.ORG Wed Apr 29 12:39:47 2015 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 209E1915 for ; Wed, 29 Apr 2015 12:39:47 +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 D682219BD for ; Wed, 29 Apr 2015 12:39:46 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A2CsBADGz0BV/95baINcg19cBYMVwm+BSQqFNk4CgXwTAQEBAQEBAYEKhCABAQEDAQEBASArIAsFFg4KAgINGQIpAQkmBggHBAEcBIgCCA2yfpQbAQEBAQEBAQEBAQEBAQEBAQEBAQEBF4EhiheEMwEBHDQHgmiBRQWVc4QPg1M9kEiDUCOCBxyBbSIxB4EEOYEBAQEB X-IronPort-AV: E=Sophos;i="5.11,671,1422939600"; d="scan'208";a="208541945" Received: from muskoka.cs.uoguelph.ca (HELO zcs3.mail.uoguelph.ca) ([131.104.91.222]) by esa-annu.net.uoguelph.ca with ESMTP; 29 Apr 2015 08:39:43 -0400 Received: from zcs3.mail.uoguelph.ca (localhost.localdomain [127.0.0.1]) by zcs3.mail.uoguelph.ca (Postfix) with ESMTP id C7EC5B3F7E; Wed, 29 Apr 2015 08:39:43 -0400 (EDT) Date: Wed, 29 Apr 2015 08:39:43 -0400 (EDT) From: Rick Macklem To: Paul Thornton Cc: freebsd-net@freebsd.org Message-ID: <27489106.27851938.1430311183809.JavaMail.root@uoguelph.ca> In-Reply-To: <5540A9BF.2090003@prt.org> Subject: Re: Frequent hickups on the networking layer MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [172.17.95.12] X-Mailer: Zimbra 7.2.6_GA_2926 (ZimbraWebClient - FF3.0 (Win)/7.2.6_GA_2926) X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Apr 2015 12:39:47 -0000 Paul Thornton wrote: > Hi, > > On 28/04/2015 22:06, Rick Macklem wrote: > > ... If your > > net device driver is one that allocates 9K jumbo mbufs for receive > > instead of using a list of smaller mbuf clusters, I'd guess this is > > what is biting you. > > Apologies for the thread drift, but is there a list anywhere of what > drivers might have this issue? > If you: # cd /usr/src/sys/dev # find . -name "*.c" -exec fgrep -l MJUM9BYTES {} \; you will get a hint w.r.t. which ones might have a problem. Then I think you'll have to dig into the driver sources to see what it is actually doing. (As you've seen on the thread Chelsio sounds like it handles things and allows you to disable use of 9K via a tunable.) rick ps: Long ago (1970s) a CS prof. I had said "the sources are the only real documentation". I think he was correct. > I've certainly seen performance decrease in the past between two > machines with igb interfaces when the MTU was raised to use 9k > frames. > > Paul. > _______________________________________________ > 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" >