From owner-freebsd-net@FreeBSD.ORG Mon Feb 3 07:25:03 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 EBA1DBE1; Mon, 3 Feb 2014 07:25:03 +0000 (UTC) Received: from mail-ee0-x233.google.com (mail-ee0-x233.google.com [IPv6:2a00:1450:4013:c00::233]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 5DED816B6; Mon, 3 Feb 2014 07:25:03 +0000 (UTC) Received: by mail-ee0-f51.google.com with SMTP id b57so3461711eek.10 for ; Sun, 02 Feb 2014 23:25:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=SDb/XulB9WCVRuWy4y51DrK8TGTA+OOOuy9B3XtMIgM=; b=sShcawe+quWD6RH9UjAIwFxwUvdlcpqPufteDBtPS3jzTluBOH98wqOl5KLt1plxPs 74eCL63i5Ulk7CPfjbyHmgcENnIiKlVTsDnq7aVJaSk09FMhfRbrau3fgwCKnrO5aDfO VAzGX4B/ajPly2cYn4oaFVGUsgtGad3yjxJettQ9j2NHwuzdH5VERGalcTkJJO8o4N6h rl15KbsdzbIQlQbkk6Tgi4i77Qcq1Br4MPiDJN23j42kK/XO+8dUEchDrEQFq1Y5r8Hl L9BKv4bHSHP0OdzEX8Ai0DkTd5UYC4bZTBKHYeQCJ8T51Un8PhUmDUQ88xQ13D/2wO3/ BIaw== MIME-Version: 1.0 X-Received: by 10.14.39.3 with SMTP id c3mr6654199eeb.42.1391412300906; Sun, 02 Feb 2014 23:25:00 -0800 (PST) Received: by 10.14.65.4 with HTTP; Sun, 2 Feb 2014 23:25:00 -0800 (PST) In-Reply-To: References: Date: Sun, 2 Feb 2014 23:25:00 -0800 Message-ID: Subject: Re: Errors using span interface on if_bridge(4) From: hiren panchasara To: "freebsd-net@freebsd.org" , Jack F Vogel Content-Type: text/plain; charset=UTF-8 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: Mon, 03 Feb 2014 07:25:04 -0000 Alright. I am having a "mind blown" moment right now. While reporting this checksum error issue, I always had ix3 (the culprit interface) being monitored via tcpdump in other tmux session. Something gotten into me and I stopped monitoring it and everything was kosher after that. Not a single checksum error! Just to be sure, I kldunloaded/loaded if_ixgbe (as I've built that as a module) to reset all the stat counters and ran my tests again using both iperf3 and netperf - and saw same behavior. If I start tcpdump on interface again, the dev.ix.3.mac_stats.checksum_errs starts going up. Stopping tcpdump would stop the counter from incrementing. Why is that happening? I have no clue. How/why is tcpdump affecting this interface traffic stats in such a way? Just as a recap, bridge0 has ix1 as a member and ix2 as a span interface. ix2 and ix3 are connected back to back so that I can monitor traffic coming to bridge0 on ix3 (as ix2 will forward it all being a span interface). cheers, Hiren