Lag spikes in full sim

[Courgan Barzane]

Hello all,

since 4 days we got a lag problem in sim.

Every 70 seconds there is a spike, obviously due to an increase in PHYSICS TIME to above 22ms for a second, bringing the sim to a full stop. Obviously you think about a bad rezzer or something that bumps badly into something due to a timed script, but disabling scripts won't stop it. So we are a bit clueless now.

What is making the thing hard is that the whole sim was rebuild just barely before it, so it could be anything, although I tend to believe that due to the fact that it didn't occur in the sim where we built it before, the main build should not be a problem, even though a few believe it might be due to the amount of mesh I used.

Any Ideas what might be responsible for it if its not a scripted device? The sim values otherwise are pretty good, less than 7000 LI, scripts under 3 ms, no collisions, nothing.. Just every 70 sec precisely the physics time goes up to 23 ms and then falls back to normal 0.3 ms.

[Emma Krokus]

I really am no expert but I wondered if someone could be wearing a script that updates every now and then? Disabling scripts in the sim wouldn't stop that if the script in the attachment was already running...

 

[Courgan Barzane]

Certainly ist not because of such.. it shows when I am alone in sim.. and it shows when I am not there.

 

Right now we are thinking it has something to do with pathfinding, since when switching it off the lag is still there but greatly reduced. Now trying rebaking the meshplane to kill it fully, but somehow it won't rebake fully seemingly as the Icon never vanishes.

[Freya Mokusei]

Do you have anything rezzed on the sim that is Temporary?

Some 'creative' people use 'temp rezzers' to rez complicated objects (approx. every 70s), in order to save prims. The more complex this object is, the more cleaning up is required. This can also affect the Navmesh (pathfinding) and create collision events.

[Courgan Barzane]

I doubt it, but cannot be sure. Unfortunately I am not simowner, just one of the two builders, so I can only give hints to the owners what to look for and don't see it myself.

Rezzer is certainly possible, what is making me doubt though is the fact that it seemingly was still going on when every script was disabled.

[Courgan Barzane]

ok, some further Information:

switching off pathfinding lessens the Problem. What is astonishing is that still the rebake navmesh button is there even when switched off.

Pathfinding view/test Shows a very interesting behavior: Permanently you get a circle of Messages.

1. Navmesh on server has changed on the server. Downloading the latest navmesh

afterwards: 2. Latest navmesh has been downloaded

then starting over again.

Rebaking Shows no effect (yes, estate admin did it).

[Cerise Sorbet]

Ohhhh, that bug seems to be familiar. Check if this applies to you --

http://wiki.secondlife.com/wiki/Beta_Server_Office_Hours/Minutes/2013-06-27

 

[2013/06/27 15:11]  Maestro Linden: certain regions have continuous navmesh rebaking, which causes some annoying UI effects and hurts performance a bit[2013/06/27 15:11]  Margithe: is it only pathfinding enabled regions then?[2013/06/27 15:12]  VoidPointer Linden: no[2013/06/27 15:12]  Maestro Linden: this issue only affects regions which have >1 parcel, but have 100% submerged parcel boundaries[2013/06/27 15:12]  Whirly Fizzle: Bet that one was fun to track down heh[2013/06/27 15:13]  Maestro Linden: Yeah, Void can talk to that [2013/06/27 15:13]  Whirly Fizzle: Bizarre repro![2013/06/27 15:13]  Margithe: ack, so it's like every island type estate..[2013/06/27 15:13]  VoidPointer Linden: wellllll, no, it was pretty easy once I saw what was happening[2013/06/27 15:13]  arton Rotaru: glad our region is only one parcel^^[2013/06/27 15:14]  VoidPointer Linden: So, as part of the STAY_WITHIN_PARCEL changes, I needed to change the way the navmesh is constructed. This involved making sure that every region did a rebake once.[2013/06/27 15:14]  VoidPointer Linden: Unfortunately, the criteria that I used to test whether a region needed rebaking had a flaw - it can't see parcel edges underwater for some reason[2013/06/27 15:15]  Maestro Linden: I believe that's because the navmesh doesn't include areas below sea level[2013/06/27 15:15]  VoidPointer Linden: so if a region has more than 1 parcel and has no parcel edges above water, then it thinks it needs to rebake. So it does[2013/06/27 15:15]  Nalates Urriah: The server gerbils probably can't swim...[2013/06/27 15:16]  Maestro Linden: there's a workaround, if your region is affected: simply subdivide a chunk of your parcel which is below sea level[2013/06/27 15:16]  VoidPointer Linden: The fix was pretty easy once I realized what was going on, but by then it was too late. So, the fix is in, but needs to go through testing, etc.[2013/06/27 15:16]  VoidPointer Linden: yes, as long as at least some part of a parcel boundary (that is not also a region border!) is found, it will not require a rebake.

 

[Courgan Barzane]

oh, that sounds pretty familiar.. THANKS a lot

will tell the owners to parcel out a small corner, we need anyways one for a doorserver. Will tell if it was it.

[Courgan Barzane]

OK.. that was the solution..

We merged the small parcel we had seperated and the lag was gone instantly. Thanks a lot for giving the hint, we were already feeling pretty dumb...

[Cerise Sorbet]

That is my favorite thing about obscure bugs, that "ah good, at least I didn't break it!" at the end  Glad to see the problem's gone.