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From: John Baldwin <jhb@freebsd.org>
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	(bigwig.baldwin.cx); Thu, 19 Apr 2012 09:58:16 -0400 (EDT)
Cc: Luigi Rizzo <rizzo@iet.unipi.it>, Sean Bruno <seanbru@yahoo-inc.com>,
	Jack Vogel <jfvogel@gmail.com>
Subject: Re: igb(4) Raising IGB_MAX_TXD ??
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On Wednesday, April 18, 2012 7:40:17 pm Sean Bruno wrote:
> 
> On Wed, 2012-04-18 at 09:49 -0700, Sean Bruno wrote:
> > ok, good.  that at least confirms that I correctly translated between
> > the driver code and documented specification.  
> > 
> > I will try 8k as a test for now and see how that runs.  
> > 
> > sean
> 
> For now, I've patched one front end server with: 
> /usr/src/sys/dev/e1000/if_igb.h:#define IGB_MAX_RXD             4096 * 4
> 
> And adjusted hw.igb.rxd: 8192
> 
> So far so good, been running in production for a couple of hours so the
> "smoke test" for this setting seems to be happy.
> 
> We'll continue to adjust and test tomorrow during higher load
> conditions.

FWIW, at my current employer we run with both rxd and txd cranked up to 32k 
(we had to patch the driver as you suggested) and have not had any problems 
doing that for a couple of years now.

-- 
John Baldwin