Bandwidth and Sim Idling...a question

[Ayesha Askham]

This question formed in my head in the wee small hours of this morning and while I know next to nothing about programming and software, this possibly idiotic scenario has stayed with me so far during the day when my more ridiculous dreams are rationalised away.

So I am hoping that someone who DOES know their programming stuff will point out to me just how daft my idea is, and I will sleep peacefully tonight.

We know that two of the most important changes to Secondlife's programming recently have been Sim-idling and dynamic Pathfinding. 

We also know that Linden Lab uses dedicated teams on such projects. 

We know that workers on these teams do not often talk to each other, especially if there is a lot of time-pressure on them to get their project up and running.

So: is it possible that unbeknown to the teams thus committed, that dynamic Pathfinding is in some way incompatible with Sim idling? 

Has it anything to do with the new Havok physics?

One of the most commonly observed spamming messages concerns "adding sim...sim already exists...removing sim...", this in addition to the "Parceloverlay reliable" spam.  Could this have anything to do with this proposed incompatibilty?

I am confidently expecting to be told how stupid this idea is, but at least then I will know.

[Echo Hermit]

Do we really know ...

"We know that workers on these teams do not often talk to each other, especially if there is a lot of time-pressure on them to get their project up and running."

... or do we just (have good reason to) suspect it? (A comment I wanted to put there has had to be held back, or no doubt this thread would be pulled as it is too controversial, and seemingly anti-Linden, which - you know - I am not).

It's odd what comes to you in the wee small hours, isn't it? And I hope one of the many clever souls who are always so willing to declare themselves as programmers will be able to shed some light on the possibility of your theory.

I would like to know how important region idling is to LL; I found I felt insecure when it was mentioned, because I don't know the speed an idle region can come back into activity again when it sees/senses a child agent approaching.  Also, I would like to know how LL feel about certain bot avatars preventing region idling in sims because of their 24/7 presence meaning some sims very rarely get a chance to go idle.

 

[Theresa Tennyson]

I'm not going to say that your idea is stupid but there are many reasons why it's extremely unlikely.

1) Pathfinding and region idling have been running together for weeks/months and this has only popped up recently.

2) They don't seem to have THAT many systems engineers at Linden Lab - the same people are usually associated with many projects, at least server side.

3) An idling region never stops existing - it only runs more slowly. It's not like the new cars that shut their engines off when you take your foot off the gas, it's like an older car that, well, idles - the engine runs just fast enough to keep running.

4) This seems to be caused by a glitch with diagonally touching regions, which are unusual in an important respect. If a series of regions are laid out as a checkerboard and only touching at the corners they're supposed to be invisible to each other. You can see swaths of private regions laid out like this on the map. If other regions fill in the blanks in the checkerboard, though, diagonally touching regions ARE supposed to be visible because they form part of a continuous area. Don't ask me why they work this way; don't ask me if this is a good idea. It probably isn't a good idea for English to have three hundred different ways to pronounce the letters "-ough" but that's how things ended  up being built. There was a JIRA about diagonal visibility of sims that came up right before this issue popped up and that may have been the window the bug flew in through.

[Ayesha Askham]

OK

It looks like I have at least got folk talking about this.  I looked at a reference to PATHBUG-175 on the JIRA...

There ARE similarities, but I don't agree with Theresa that this bandwidth issue is unrelated to sim idling issues.  For one thing I do not think that the mere existence of the sim is the trigger.  What may be happening is that on idle sims with this new Havok physics objects, or maybe even the sim server itself is not receiving a comm from neighbouring sims within a timeout limit and is thus retrying endlessly to establish a link, despite other links being confirmed, hence the "adding region...region already exists...removing region" spam.

Whatever, it would be nice if Linden Lab was to communicate its situation and findings outside the Beta Server Group.  But that would involve communication with us, the great unwashed...oops how silly of me!

[Drongle McMahon]

I'm not sure about this, but I did get the excess bandwidth thing at least once when the diagonally opposite region had green dots in it. If there were indeed people there, then it wouldn't have been idling, would it?. However, the world map may not be completely updated at that point, so I guess a doubt remains. Anyone else notice this?

[Qie Niangao]

Well, it would have to be a more subtle incompatibility than that. As far as I can tell, the bandwidth problem still arises when none of the relevant sims have gone idle.

That doesn't rule out a possible code conflict, but... well, this is just my suspicion, but personally I'll be a little surprised if it turns out to be related to either Pathfinding or sim idling.

[Ayesha Askham]

Qie

I respect your opinion, and so I may well be misattributing the phenomenon.  But, it is not the change of state that may cause this, indeed it may simply be some element in the code that governs sim idling that conflicts with some element of the code governing Havok 2012 physics or dynamic pathfinding.

What is rapidly becoming clear to me is that, as you say, it is a subtle and elusive issue.  I just wonder how much patience the disenfranchised users will have with Linden Lab if they do not come out and say something about the issue.

Once lost, I very much doubt that these folk will return to SL, Steam or no Steam.  That is bad, very bad.

[Qie Niangao]

Yeah, I really am just speculating anyway.

I so wish it weren't impossible for me to attend the Server user group meeting this afternoon to find out what Andrew reports for progress.  As I mentioned somewhere, Andrew said he was taking on this problem at Tuesday's meeting. Maybe somebody who can attend will be able to update us here.

(I'd love to attend for another, unrelated reason: I want to encourage server-side folks to have a scripting interface to the new Materials system, the day it arrives. I had a little epiphany about how awesome that could be. Oh well, that can wait for next week.)

[Heart Brimmer]

How can I find out exactly how much bandwidth I use? Thanks in Advance. 

[Dilbert Dilweg]

Google search a "Banwidth Monitor" you can find some free ones. some freeware that allows 10 sensors.. you could sensor SL and see how much it is pulling

[WolfBaginski Bearsfoot]

Thing is, right from the beginning, SL had to have diagonal visibility. It was necessary for the first group of regions, the original mainland. Did they try to hack that when the first private islands were sold? I don't see any good reason why such islands have to be corner to corner at all.

And there seem to be two distinct sorts of message spewing going on. Some of it is associated with Magnum RC sims, and involve one message. Some is associated with LeTigre, involves the two southern sim corners, and a different sort of server ->viewer message. It's enough difference that I find it hard to see the relationship.

Thing is, there are things the Lindens never officially tell us about. Like the way the're reducing from three server centres to two. When it finally gets finished sim crossing should improve. It might be affecting that sim-corner thing as well. But the Operations Team (that's the name I've seen used for them) seems about as talkative as a pet rock. Even when they're restarting sims for an OS upgrade, the only way you can tell they have finished is when sims stop going down.

Come to think of it, sims do seem to have been going down a lot recently, and nobody has said anything.

 

[WolfBaginski Bearsfoot]

"Materials" could easily get out of hand, but I'd agree that being able to manipulate the various "special" textures in the same way as a normal texture would be good. By that, I mean offsets, tiling, and rotations, the basic texture animation elements. I have a globe which is a fixed prim. It rotates by moving the texture. If I used a normal map to show the mountains, that would have to be animated too.

(I have come to the view that Linden Labs often only gets the obvious with the help of a large hammer.)

[WolfBaginski Bearsfoot]

The Stats (Ctrl-Shift-1) window gives you a live indicator, but misses  things such as streaming media. Normal use varies with Draw Distance, but would usually be under 100kbps. There would be spikes when new people come into view, or you TP to a new location.

One reason I think there are distinct bugs is that one class of spew maxes out between 600 kbps and 700 kbps, while another just goes straight to the maximum speed of my connection.

An external monitor will let you keep track of totals.

 

[JoyofRLC Acker]

Various thoughts:

Colour me naive but I think an external monitor would be an exellent thing.  It would be good to veryfy that the stats bar BW is not incorrect.

The spam (variius flavours) is undenaible,   I wonder too how cleints cope with large log files.

I have a nasty feeling this is going to turn out to be a very subtle / deep / obsucyre "bug".

I am surprised it isnt creating more comment (the JIRA votes / watches are not all that high and its only classed as sever not showstopper.

[Hitomi Tiponi]

---

Theresa Tennyson wrote:

4) This seems to be caused by a glitch with diagonally touching regions, which are unusual in an important respect. If a series of regions are laid out as a checkerboard and only touching at the corners they're supposed to be invisible to each other. You can see swaths of private regions laid out like this on the map. If other regions fill in the blanks in the checkerboard, though, diagonally touching regions ARE supposed to be visible because they form part of a continuous area. Don't ask me why they work this way; don't ask me if this is a good idea. It probably isn't a good idea for English to have three hundred different ways to pronounce the letters "-ough" but that's how things ended  up being built. There was a JIRA about diagonal visibility of sims that came up right before this issue popped up and that may have been the window the bug flew in through.

---

The invisibility of diagonal regions in all ways was how it used to be.  There now may be some interaction as you can walk up to about 10 metres into an adjacent region that is offline as part of the sim crossing changes (or you could last time I tried).  I'm wondering if this change has caused more overlap.