Comments on: 21 http://xyzzyxyzzy.net/2009/06/19/21/ ...you are in a grid of twisty, little links, all alike. there's a teleport gate here. Fri, 16 Dec 2011 14:43:27 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Darryl http://xyzzyxyzzy.net/2009/06/19/21/comment-page-1/#comment-305 Darryl Fri, 03 Jul 2009 00:32:19 +0000 http://xyzzyxyzzy.net/?p=334#comment-305 <p>I would be inclined to tinker with priorities at the content level rather than at the thread level...</p> I would be inclined to tinker with priorities at the content level rather than at the thread level…

]]> By: Justin Clark-Casey http://xyzzyxyzzy.net/2009/06/19/21/comment-page-1/#comment-304 Justin Clark-Casey Thu, 02 Jul 2009 22:09:36 +0000 http://xyzzyxyzzy.net/?p=334#comment-304 <p>I would intuitively agree with your analysis about texture requests starving existing users Dr S - this is the kind of phenomenon that I've seen before in OpenSim office hour meetings. Although originally it appeared to be associated simply with the login process (though maybe it really was texture starvation underneath that).</p> <p>Hence, my original thought was to change the relative thread priorities so that during login, client threads got a much lower thread priority than existing clients. However, in looking down into Mono, I discovered that thread prioritization was completely unimplemented, only the stubs existed.</p> <p>I don't know whether changing thread priorities within the VM would make a huge amount of difference or be all that relevant on Linux (which I assume you're using for the tests!) but there wasn't any opportunity to try.</p> <p>AFAIR, this was back on Mono 2.0.1 so things may have changed since then.</p> I would intuitively agree with your analysis about texture requests starving existing users Dr S – this is the kind of phenomenon that I’ve seen before in OpenSim office hour meetings. Although originally it appeared to be associated simply with the login process (though maybe it really was texture starvation underneath that).

Hence, my original thought was to change the relative thread priorities so that during login, client threads got a much lower thread priority than existing clients. However, in looking down into Mono, I discovered that thread prioritization was completely unimplemented, only the stubs existed.

I don’t know whether changing thread priorities within the VM would make a huge amount of difference or be all that relevant on Linux (which I assume you’re using for the tests!) but there wasn’t any opportunity to try.

AFAIR, this was back on Mono 2.0.1 so things may have changed since then.

]]> By: DrScofield http://xyzzyxyzzy.net/2009/06/19/21/comment-page-1/#comment-302 DrScofield Wed, 24 Jun 2009 05:49:59 +0000 http://xyzzyxyzzy.net/?p=334#comment-302 <p>good idea! sean also brought that up when we discussed this yesterday. need to figure out how complex this is. :-)</p> good idea! sean also brought that up when we discussed this yesterday. need to figure out how complex this is. :-)

]]> By: Darryl http://xyzzyxyzzy.net/2009/06/19/21/comment-page-1/#comment-301 Darryl Wed, 24 Jun 2009 02:53:12 +0000 http://xyzzyxyzzy.net/?p=334#comment-301 <p>One thing that occurred to me when i logged in to what seemed a very slow grid the other day was that the server was trying to feed me all the prim data that was in view, all at the same time.</p> <p>Would it help to have the server queue prim downloads and sort by distance to the agent, to get the closest prims to render fully soonest?</p> One thing that occurred to me when i logged in to what seemed a very slow grid the other day was that the server was trying to feed me all the prim data that was in view, all at the same time.

Would it help to have the server queue prim downloads and sort by distance to the agent, to get the closest prims to render fully soonest?

]]> By: DrScofield http://xyzzyxyzzy.net/2009/06/19/21/comment-page-1/#comment-300 DrScofield Mon, 22 Jun 2009 18:04:47 +0000 http://xyzzyxyzzy.net/?p=334#comment-300 <p>@dan: interesting point. we are currently looking into the packet processing parts to see where we can reduce the numbers of objects created (there are a couple of places that, at least at first sight, appear a bit "trigger happy" with regards to object instantiation).</p> @dan: interesting point. we are currently looking into the packet processing parts to see where we can reduce the numbers of objects created (there are a couple of places that, at least at first sight, appear a bit “trigger happy” with regards to object instantiation).

]]> By: Dan Lake http://xyzzyxyzzy.net/2009/06/19/21/comment-page-1/#comment-299 Dan Lake Mon, 22 Jun 2009 17:57:07 +0000 http://xyzzyxyzzy.net/?p=334#comment-299 <p>One difference I have noticed between libomv bots and "real" clients/viewers is the number of packets they generate for the exact same behavior. For example, if you use libomv testclient to mimic the "forward" action, it sends packets to the server indicating the up arrow is depressed. The same packets come from the Hippo viewer but the rate is much much higher. There are some example numbers I captured:</p> <p>TestClient Moving: 11 pkts/s TestClient Still: 2 pkts/s Hippo Moving: 185 pkts/s Hippo Still: 7 pkts/s</p> <p>When you consider each of 21 clients producing 185 pkts/s vs 11 pkts/s, that is a lot of extra network and scene update processing. This could be a part of the problem seen with "real" viewers. The movement resolution seems to be unnecessarily high. ~Dan</p> One difference I have noticed between libomv bots and “real” clients/viewers is the number of packets they generate for the exact same behavior. For example, if you use libomv testclient to mimic the “forward” action, it sends packets to the server indicating the up arrow is depressed. The same packets come from the Hippo viewer but the rate is much much higher. There are some example numbers I captured:

TestClient Moving: 11 pkts/s TestClient Still: 2 pkts/s Hippo Moving: 185 pkts/s Hippo Still: 7 pkts/s

When you consider each of 21 clients producing 185 pkts/s vs 11 pkts/s, that is a lot of extra network and scene update processing. This could be a part of the problem seen with “real” viewers. The movement resolution seems to be unnecessarily high. ~Dan

]]> By: Grumly http://xyzzyxyzzy.net/2009/06/19/21/comment-page-1/#comment-298 Grumly Mon, 22 Jun 2009 12:25:33 +0000 http://xyzzyxyzzy.net/?p=334#comment-298 <p>Is it possible to make the textures delivered externally ? I mean, not by the simulator itself ? The same way as website do, for example ?</p> Is it possible to make the textures delivered externally ? I mean, not by the simulator itself ? The same way as website do, for example ?

]]> By: DrScofield http://xyzzyxyzzy.net/2009/06/19/21/comment-page-1/#comment-297 DrScofield Mon, 22 Jun 2009 11:11:36 +0000 http://xyzzyxyzzy.net/?p=334#comment-297 <p>@dirk: two comments on that:</p> <ol> <li><p>dahlia's max was 21 avatars, our calamities started once we went past that number</p></li> <li><p>my suspicion is that the problem would not have occurred if the arrival rate of our users had been lower (that is, the time between login attempts had been longer). with lots of users getting logged in at once, we saw a packet explosion --- probably caused by the viewers all requesting all the textures at once.</p></li> </ol> @dirk: two comments on that:

  1. dahlia’s max was 21 avatars, our calamities started once we went past that number

  2. my suspicion is that the problem would not have occurred if the arrival rate of our users had been lower (that is, the time between login attempts had been longer). with lots of users getting logged in at once, we saw a packet explosion — probably caused by the viewers all requesting all the textures at once.

]]> By: Dirk Krause http://xyzzyxyzzy.net/2009/06/19/21/comment-page-1/#comment-296 Dirk Krause Mon, 22 Jun 2009 10:31:45 +0000 http://xyzzyxyzzy.net/?p=334#comment-296 <p>This comes somewhat as a surprise, because I remember the meeting on Dahlia's Server from last year, sporting over 20 people without too much problems.</p> <p>I posted her mail from the list with the details here: http://tinypaste.com/07003</p> <p>Best, Dirk</p> This comes somewhat as a surprise, because I remember the meeting on Dahlia’s Server from last year, sporting over 20 people without too much problems.

I posted her mail from the list with the details here: http://tinypaste.com/07003

Best, Dirk

]]> By: DrScofield http://xyzzyxyzzy.net/2009/06/19/21/comment-page-1/#comment-295 DrScofield Mon, 22 Jun 2009 09:37:06 +0000 http://xyzzyxyzzy.net/?p=334#comment-295 <p>perhaps we should run the stress tests at the restaurant at the end of the universe?</p> perhaps we should run the stress tests at the restaurant at the end of the universe?

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