From owner-freebsd-ipfw@FreeBSD.ORG  Tue Feb 21 14:35:33 2006
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Date: Tue, 21 Feb 2006 06:35:33 -0800
From: Luigi Rizzo <rizzo@icir.org>
To: Donald Baud <donaldbaud@yahoo.com>
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References: <20060221141201.44390.qmail@web37406.mail.mud.yahoo.com>
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	from donaldbaud@yahoo.com on Tue, Feb 21, 2006 at 06:12:01AM -0800
Cc: freebsd-ipfw@freebsd.org
Subject: Re: Patch to add burst to dummynet ?
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On Tue, Feb 21, 2006 at 06:12:01AM -0800, Donald Baud wrote:
> Looking back in the mailing archives http://docs.freebsd.org/cgi/getmsg.cgi?fetch=62536+0+archive/2003/freebsd-ipfw/20030907.freebsd-ipfw , I found a message saying that it would be trivial to add burst support in dummynet.
> In that message, it says to change in ip_dummynet.c :
> 
> -       if (len_scaled > q->numbytes )
> +       if (len_scaled > q->numbytes + q->burst_size)
> 
> I did that, even tried len_scaled = 0
> But I don't see any difference after recompiling, kldunload/kldload dummynet.
> 
> I still get the same throughput with wget --progress=dot some_file

of course you get the same throughput!
the burst is just a constant in the time it takes to transfer data,
and it is independent of the data size. irrespective of the file
size you'll just finish (burst_size/bandwidth) seconds earlier.

cheers
luigi