From owner-freebsd-net@FreeBSD.ORG  Wed Oct 24 18:16:17 2012
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
Delivered-To: freebsd-net@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
 by hub.freebsd.org (Postfix) with ESMTP id 30B11364;
 Wed, 24 Oct 2012 18:16:17 +0000 (UTC) (envelope-from jhb@freebsd.org)
Received: from bigwig.baldwin.cx (bigknife-pt.tunnel.tserv9.chi1.ipv6.he.net
 [IPv6:2001:470:1f10:75::2])
 by mx1.freebsd.org (Postfix) with ESMTP id F21B38FC08;
 Wed, 24 Oct 2012 18:16:16 +0000 (UTC)
Received: from jhbbsd.localnet (unknown [209.249.190.124])
 by bigwig.baldwin.cx (Postfix) with ESMTPSA id 5FDA2B95E;
 Wed, 24 Oct 2012 14:16:16 -0400 (EDT)
From: John Baldwin <jhb@freebsd.org>
To: Jack Vogel <jfvogel@gmail.com>
Subject: Re: ixgb TSO performance degrades by ~30% between 7.4 and 8.2/9.0/9.1
Date: Wed, 24 Oct 2012 14:11:49 -0400
User-Agent: KMail/1.13.5 (FreeBSD/8.2-CBSD-20110714-p20; KDE/4.5.5; amd64; ; )
References: <CAGH67wTjVw8O7i9OCvHVJjVjCAXsNHNhs0LobDi4G9iukgf+eQ@mail.gmail.com>
 <201210241107.10775.jhb@freebsd.org>
 <CAFOYbcmUSfEUcQa38HF_dk5CzPUBFa0gpAA+fLqjPjgL6V-sHQ@mail.gmail.com>
In-Reply-To: <CAFOYbcmUSfEUcQa38HF_dk5CzPUBFa0gpAA+fLqjPjgL6V-sHQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: Text/Plain;
  charset="iso-8859-15"
Content-Transfer-Encoding: 7bit
Message-Id: <201210241411.49656.jhb@freebsd.org>
X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7
 (bigwig.baldwin.cx); Wed, 24 Oct 2012 14:16:16 -0400 (EDT)
Cc: Garrett Cooper <yanegomi@gmail.com>, freebsd-net@freebsd.org,
 Jack F Vogel <jfv@freebsd.org>
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-net>,
 <mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
 <mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 24 Oct 2012 18:16:17 -0000

On Wednesday, October 24, 2012 11:38:01 am Jack Vogel wrote:
> On Wed, Oct 24, 2012 at 8:07 AM, John Baldwin <jhb@freebsd.org> wrote:
> 
> > On Tuesday, October 23, 2012 6:57:01 pm Garrett Cooper wrote:
> > > Hi,
> > >
> > > Doing some poking around at the ixgb driver with a card I have at
> > > $work using netperf and two machines hooked up over crossover, I
> > > discovered that while ixgb's throughput performance was fantastic on
> > > 7.3/7.4, thoughput performance of the card is degraded on 8.2/9.0/9.1
> > > by ~30% (9400Mbps on 7.4 -> 6294Mbps on 9.0 for example). LRO
> > > performance on the other hand is fantastic and doesn't degrade with
> > > the card across FreeBSD versions. Performance remains constant with
> > > ixgb across 8.2/9.0/9.1. I didn't observe the CPU usage.
> >
> > Interesting, maybe as an experiment try hacking the #ifdef's to use
> > if_start() instead of if_transmit().
> >
> >
> That's not a bad idea, I have had cases, for instance some UDP intensive
> loads, where I found better performance with the old interface. This was one
> reason why I had wanted to change the ifdef's to not just be an OS version
> level, making either more easily selectable.

In this case, if using if_start() helps, then I'd like Garrett to try
my current ixgbe patch from the other thread as well to reduce concurrent
RX processing.

-- 
John Baldwin