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Date:      Mon, 01 Jul 2002 12:23:08 -0700
From:      Terry Lambert <tlambert2@mindspring.com>
To:        Mike Silbersack <silby@silby.com>
Cc:        Doug Barton <DougB@FreeBSD.org>, hawkeyd@visi.com, freebsd-hackers@FreeBSD.org
Subject:   Re: ftp and mail much slower into fbsd 4.4 vs and old BSDi
Message-ID:  <3D20AC1C.72B60BC2@mindspring.com>
References:  <20020701135548.Y86208-100000@patrocles.silby.com>

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Mike Silbersack wrote:
> On Mon, 1 Jul 2002, Doug Barton wrote:
> > The problem is that Terry has described the theory, whereas many of us
> > who have observed the situation in the real world have noticed that even
> > on a homogenous network (all with newreno enabled) performance is still
> > worse than with newreno disabled.

I guess you missed the part where I said that FreeBSD had bugs, and
Matt Dillon posted patches?

You guys are acting like this is something new that was recently
discovered, like the recent SlashDot story on initial sequence
numbers, which was first published a year and a quarter ago, but
is somehow now magically, once again, "news".


> > I don't have enough network stack fu to debug or improve this, but I
> > have enough experience with it to know that off is better. For you, I'd
> > say turning it off is the first thing you should test, and see what
> > happens.
> 
> I've been meaning to investigate, but I keep getting sidetracked...
> 
> But yeah, I agree with you.  Going back to plain reno isn't the end of the
> world; it's still behaves decently and won't cause problems.

"Off" has higher performance in the absence of congestion.

If you can guarantee no congestion, I'd like to purchase network
connectivity from you.


I guess I will have to repeat Matt Dillon's postings verbatim to
make the points that Matt, Poul, and others made with regard to
NewReno and the FreeBSD failure case, as well as the workaround?

"Off" is not the answer; "fix it" is the answer.  If you can't
do that, then "use Matt's workaround" is the answer.

FWIW, Matt's workaround turns off NewReno for specific instances
where it's known to fail because of trigerring on an incorrect
one packet boundary, but it doesn't turn it off completely.

This whole problem comes up every month or two, and has been
known since NewReno was integrated, and has been characterized
since Matt first looked at it in depth and provided patches.

If you are running an old FreeBSD, then manually apply Matt's
patches from the previous threads where this issue was discussed
to death.

-- Terry

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