To: "David S. Miller" <davem@davemloft.net>
Cc: mlleinin@hpcn.ca.sandia.gov, netdev@vger.kernel.org,
       linux-kernel@vger.kernel.org, openib-general@openib.org,
       shemminger@osdl.org
Subject: Re: [openib-general] Re: TSO and IPoIB performance degradation
References: <1141776697.6119.938.camel@localhost>
	<20060307.161808.60227862.davem@davemloft.net>
	<adaacc1raz9.fsf@cisco.com>
	<20060307.172336.107863253.davem@davemloft.net>
From: Roland Dreier <rdreier@cisco.com>
Date: Tue, 07 Mar 2006 17:34:34 -0800
In-Reply-To: <20060307.172336.107863253.davem@davemloft.net> (David S. Miller's message of "Tue, 07 Mar 2006 17:23:36 -0800 (PST)")
Message-ID: <ada4q29ra6t.fsf@cisco.com>
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    David> I wish you had started the thread by mentioning this
    David> specific patch, we wasted an enormous amount of precious
    David> developer time speculating and asking for arbitrary tests
    David> to be run in order to narrow down the problem, yet you knew
    David> the specific change that introduced the performance
    David> regression already...

Sorry, you're right.  I was a little confused because I had a memory of
Michael's original email (http://lkml.org/lkml/2006/3/6/150) quoting a
changelog entry, but looking back at the message, it was quoting
something completely different and misleading.

I think the most interesting email in the old thread is
http://openib.org/pipermail/openib-general/2005-October/012482.html
which shows that reverting 314324121 (the "stretch ACK performance
killer" fix) gives ~400 Mbit/sec in extra IPoIB performance.

 - R.
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