From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-x22a.google.com (mail-ua0-x22a.google.com [IPv6:2607:f8b0:400c:c08::22a]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id A83583B25D for ; Mon, 8 Aug 2016 18:13:54 -0400 (EDT) Received: by mail-ua0-x22a.google.com with SMTP id i31so129968281uai.2 for ; Mon, 08 Aug 2016 15:13:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:from:date:message-id:subject:to; bh=A3bFJi/m3j47ep5zjjuyrKp4WiO+kHH807JJH+aw/2U=; b=A3I5nun3rNMR8GJvm4S+iYynB/fhNBz+qZPEpQ2n/tVoAM9ATvOBY5V6W/frNblmpX T6EXoIjDmnc1ssx4agZTloI/+20yT9554xJDpSdf7jM2QBOJW488+oofRo1dfdYOgA0L BjTcJAv9wSTptl/acNuLxcjLalZChXBURnf1g+/ZjYu1hWAJmGIzcJvhY6ECXr/sEguR ePiIabW+6tRoC+ruPdm2WQ+qUNm5Xds5w+BGXB2UCo1f0NupAdmL5EnIFj27Xowndv6n OS+iUVLCgmwcapRNh8+YAyYohXUr+wIN2JEuCA5wATdi62NCSLeryX4kjAB/BgdIaBzd n5Sw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=A3bFJi/m3j47ep5zjjuyrKp4WiO+kHH807JJH+aw/2U=; b=F5XZEaKalSUcxkiXWzPn1Ol2yJOFy8kfH3TSEp2qeFQ0N8Jt3OQA9AqfR/frnyqmPs +N2PBE4fZzKYJz6Qw9sZbhdPaYhnc7V/IdwS7KpG6EAlUNxYFoKxc5qcNUeTFbzCNJBW wiSKe9gmBerK3yO/e3WDtd4dYVrBtq589MXo0+NxjM1Foyes3qMq8et0B05EndmL+OjD X+Uj2oyJTpBYe7BibCuk7hdts8Asx2gFflKDN1qCv7cLmuxL/8bTXtBoR503Mu6iMxH6 U6ZG3N0cK6jP1PhCBcvNVuI6hOhPy2zwArELCuo6i5kUNQzpUvJ8OdPwHL29jQhdQC2B RAUw== X-Gm-Message-State: AEkoousvbOSruD87Kz1WliOhcP5iakL30DkrLC5JIz+JGgL3QSe552hkSw/POvbezex8vbbZ6gni22K9dPc6XQ== X-Received: by 10.31.9.67 with SMTP id 64mr48179816vkj.89.1470694433875; Mon, 08 Aug 2016 15:13:53 -0700 (PDT) MIME-Version: 1.0 Received: by 10.103.132.67 with HTTP; Mon, 8 Aug 2016 15:13:53 -0700 (PDT) From: Aaron Wood Date: Mon, 8 Aug 2016 15:13:53 -0700 Message-ID: To: bloat Content-Type: multipart/alternative; boundary=001a11440ef44ded28053996bbce Subject: [Bloat] Intel recommends against LRO in routing and bridging. X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Aug 2016 22:13:54 -0000 --001a11440ef44ded28053996bbce Content-Type: text/plain; charset=UTF-8 Just came across this at the top of the README for the ixgbe driver: ( http://downloadmirror.intel.com/22919/eng/README.txt) WARNING: The ixgbe driver compiles by default with the LRO (Large Receive Offload) feature enabled. This option offers the lowest CPU utilization for receives, but is completely incompatible with *routing/ip forwarding* and *bridging*. If enabling ip forwarding or bridging is a requirement, it is necessary to disable LRO using compile time options as noted in the LRO section later in this document. The result of not disabling LRO when combined with ip forwarding or bridging can be low throughput or even a kernel panic. -Aaron --001a11440ef44ded28053996bbce Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Just came across this at the top of the README for the ixg= be driver: (http://downloadmirror.intel.com/22919/eng/README.txt)

<= div>
WARNING:  The ixgbe driver compiles by default with the LRO (Large =
Receive
Offload) feature enabled.  This option offers the lowest CPU utilization fo=
r
receives, but is completely incompatible with *routing/ip forwarding* and
*bridging*.  If enabling ip forwarding or bridging is a requirement, it is
necessary to disable LRO using compile time options as noted in the LRO
section later in this document.  The result of not disabling LRO when combi=
ned
with ip forwarding or bridging can be low throughput or even a kernel panic=
.

-Aaron
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