Date: Tue, 21 Feb 2006 08:15:37 -0800 (PST) From: Donald Baud <donaldbaud@yahoo.com> To: Luigi Rizzo <rizzo@icir.org> Cc: freebsd-ipfw@freebsd.org Subject: Re: Patch to add burst to dummynet ? Message-ID: <20060221161537.91174.qmail@web37405.mail.mud.yahoo.com> In-Reply-To: <20060221074134.B63818@xorpc.icir.org>
next in thread | previous in thread | raw e-mail | index | archive | help
> On Tue, Feb 21, 2006 at 06:57:10AM -0800, Donald
> Baud wrote:
> >
> >
> > --- Luigi Rizzo <rizzo@icir.org> wrote:
> ...
> > > 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
> >
> > I ran two tests with the following ipfw rules:
> > ipfw pipe 10 config bw 10kbit/s
> > ipfw add 5 pipe 10 ip from 10.0.0.1 to me
> > == with: if (len_scaled > q->numbytes) ==
> > wget --progress=dot some_file
> > 0K .......... .......... 0% 1.13 KB/s
> > 50K .......... .......... 1% 1.14 KB/s
> > 100K .......... .......... 2% 1.14 KB/s
> > 150K .......... .......... 3% 1.14 KB/s
> >
> > == with: if (len_scaled > q->numbytes + 100000 )
> > wget --progress=dot some_file
> > 0K .......... .......... 0% 1.13 KB/s
> > 50K .......... .......... 1% 1.14 KB/s
> > 100K .......... .......... 2% 1.14 KB/s
> > 150K .......... .......... 3% 1.14 KB/s
>
> and so ? as i said, the throughtput is the same, you
> just see things happening a little bit (very little,
> usually) earlier,
> and your experiment has no notion of time, and
> furthermore there are so many factors influencing
> the throughput and the numbers printed by wget
> that it's hard to tell how can you see the
> difference.
>
> assuming, of course, that the patch i suggested
> works, which i
> think but cannot guarantee.
>
> cheers
> luigi
>
Are you saying that wget bandwidth reading is
incorrect? I expected to see full speed of the pipe
for the first 100KBytes.
I even commented out:
/*
if (len_scaled > q->numbytes)
break ;
*/
While I would have expected full throughput, I got
only ~10X the speed of the pipe:
0K .......... .......... 0% 8.30 KB/s
50K .......... .......... 1% 20.70 KB/s
100K .......... .......... 2% 13.80 KB/s
150K .......... .......... 3% 13.80 KB/s
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20060221161537.91174.qmail>