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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I remember you suggesting this before, +1.<o:p></o:p></span></p>
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color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Adam<o:p></o:p></span></p>
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color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> opensim-dev-bounces@lists.berlios.de
[mailto:opensim-dev-bounces@lists.berlios.de] <b>On Behalf Of </b>Stefan
Andersson<br>
<b>Sent:</b> Thursday, 2 October 2008 9:54 PM<br>
<b>To:</b> opensim-dev@lists.berlios.de<br>
<b>Subject:</b> Re: [Opensim-dev] Does OpenSim need to leave so many packets
marked as reliable?<o:p></o:p></span></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'>Guys,<br>
<br>
for some time now, I've been meaning to propose a quite different
approach, of which we've actually already done some tests with good result;<br>
<br>
the basic idea is to connect reliable packets with two
delegates; an ack delegate and a nack delegate - the implication probably
obvious:<br>
<br>
when the packet gets acked, the ack delegate is called, when it's nacked, the
nack. The packet is sent as a parameter.<br>
<br>
what this would let us do, is to use the sent packet to figure out what
the right course of action is;<br>
<br>
for an update, for example, we could look that object up and see if
it's there's been another more resent update sent; if so, we can discard
this. If not - we can _recreate_ a more recent packet and send that instead.<br>
<br>
We have done something similar for terrain, a terrain packet watchdog,
which keeps track of what patches has been acked, and resends those that
haven't after a timeout. This removes the atom bombing.<br>
<br>
Best regards,<br>
Stefan Andersson<br>
Tribal Media AB<br>
<br>
Join the 3d web revolution : <a href="http://tribalnet.se/" target="_blank">http://tribalnet.se/</a><br>
<br>
<br>
<br>
<o:p></o:p></span></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'><br>
> Date: Thu, 2 Oct 2008 21:00:44 +0100<br>
> From: jjustincc@googlemail.com<br>
> To: opensim-dev@lists.berlios.de<br>
> Subject: Re: [Opensim-dev] Does OpenSim need to leave so many packets
marked as reliable?<br>
> <br>
> Yes, it's possible that the situation is more complicated than simply
marking all packets as reliable. It's also <br>
> difficult to look at percentages since it does depends heavily on what you
do.<br>
> <br>
> Also, apologies for suggesting I would change trunk earlier. I won't be
making any changes there without more <br>
> consultation, at least certainly not any change which is non-default. I
forgot how complicated an area this is.<br>
> <br>
> <br>
> Melanie wrote:<br>
> > Hi again,<br>
> > <br>
> > there may be some object updates that can be sent unreliable. For <br>
> > instance, all that have to do with moving objects (e.g. velocity != <br>
> > 0). but the initial object update can't be lost. Any object update <br>
> > lost of the login burst is a ghost prim.<br>
> > <br>
> > Melanie<br>
> > <br>
> > <br>
> > Justin Clark-Casey wrote:<br>
> >> Hmm, I then did the obvious thing and compared it
(unscientifically) with a couple of sessions on the Linden Lab grid. <br>
> >> There, reliable packets appear to compromise approximately 40% of
the transfer.<br>
> >><br>
> >><br>
> >> -------- Original Message --------<br>
> >> Subject: Does OpenSim need to leave so many packets marked as
reliable?<br>
> >> Date: Thu, 02 Oct 2008 19:32:57 +0100<br>
> >> From: Justin Clark-Casey <jjustincc@googlemail.com><br>
> >> To: opensim-dev@lists.berlios.de<br>
> >><br>
> >> Hi there,<br>
> >><br>
> >> A vast number of the packets that we send out from OpenSim
(usually >95% according to the statistics printed to the<br>
> >> Linden viewer log on shutdown) are marked as reliable. This
requires that the viewer respond with an ack, and it just<br>
> >> doesn't appear that this is done very well when a large number of
reliables are sent. A lot of acks never come and we<br>
> >> often appear to end up resending thousands (or in the worst case
tens of thousands) of packets.<br>
> >><br>
> >> In a private experiment I've set Header.Reliable = false for the
LayerDataPacket and ObjectUpdatePacket (which appear to<br>
> >> be the greatest sent by count, and which are currently reliable
by default in libOMV). Naturally, this cuts down the<br>
> >> vast number of resends (and possibly some of the packet_out_of_order
messages that come out on the console log) without<br>
> >> any apparant ill effects. However, my testing has been pretty
limited so I'm minded to wait until Monday before making<br>
> >> any trunk changes, since then I can get a better load test with
multiple avatars (this doesn't stop anybody else testing<br>
> >> of course :-)<br>
> >><br>
> >> Any opinions on this? Is there a good reason for these packets to
remain reliable (when resends are probably rare<br>
> >> anyway)? libOMV appears to mark every packet as reliable by
default... and then OpenSim removes this from a couple of<br>
> >> them but not from others.<br>
> >><br>
> > _______________________________________________<br>
> > Opensim-dev mailing list<br>
> > Opensim-dev@lists.berlios.de<br>
> > https://lists.berlios.de/mailman/listinfo/opensim-dev<br>
> > <br>
> <br>
> <br>
> -- <br>
> justincc<br>
> Justin Clark-Casey<br>
> http://justincc.wordpress.com<br>
> _______________________________________________<br>
> Opensim-dev mailing list<br>
> Opensim-dev@lists.berlios.de<br>
> https://lists.berlios.de/mailman/listinfo/opensim-dev<o:p></o:p></span></p>
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