Piling it on: the network optimisation tests

Thursday October 11th saw a huge response to Oskar Linden’s request for assistance with network optimisation tests, with many people logging-in to Aditi to join is Beta User Group meeting (I actually made it for the first time myself, the time of his meeting is generally a little awkward for me). More were available on the IRC channel established for the test as well.

Oskar’s meeting place at Morris on Aditi.

Things got off to a rocky start; mid-way through the Beta UG meeting everyone received the royal order of the boot, and problems occurred attempting to log back in. It transpired that an SSL certificate had expired at LL’s end and had to be renewed (through until 2015). Even so, not everyone appeared to make it back (or at least, not with their primary accounts!). Maestro Linden did make it back with the rest of us, and immediately sought protection in a state-of-the-art anti-crash system from Ordinal Malaprop* created (or is that crated?). No amount of coaxing could get him out, either:

Darien Caldwell: you can come out of the box now Maestro. Crash is over ;p

Mæstro Linden (maestro.linden): I’ll come out when I feel safe 🙂

People getting back after the crash and finding we have a Maestro Linden-in the-box

The meeting also had some disruption from an unhappy camper or two complaining about bans. One of them made it back following the initial forced log-out, and as final preparations were made for the test, appeared to successfully crash the region. Shortly before this happened, concerns were raised that this individual may have been trying to disrupt the IRC test channel, as they appeared to be passing commands aimed at IRC in local chat (at one point a little later, a similar command appeared in the IRC channel, and I and a number of others were, coincidentally or otherwise, disconnected).

The testing itself proceeded pretty much as planned, with everyone logging-in to a specified region at more-or-less the same time, testing the network capabilities in handling a large number of log-in updates in a single region. From my perspective, this went well, and as one of the initial people to log-in, I didn’t appear to suffer from the kind of lag usually associated with moving around in a region where there are a large number of people arriving.

Following the en-masse arrival, we dispersed to two regions for a group chat load test. I cannot actually say how this went, as I arrived at my designated region, only to take three steps and crash (an issue at my end of the SL equation rather than anything else).

I made it back to participate in the IM tests, which comprised piling-on a mass of IMs to targeted avatars and then awaiting their reply. I think I was one of the first to IM and one of the last to get a reply, Again, not through any failure in the system, but simply because Pey’s Law affected the tester I was IMing – he replied on receiving my first message, but forgot to press ENTER to send :).

The final part of the test was a mass teleport to a specified region, again presumably to test how the network handled a large number of arrivials within a region. While this may have been a placebo effect from being on Aditi, the teleport itself seemed to me to be somewhat faster than is usual, with the progress bar merely flicking up on the screen and then vanishing as I arrived. Once, there I also found walking around with people people teleporting-in also did seem to be as prone to mini-freezes or stutters as can be the case. However, the load on the target region (selected at the last-minute due to problems with the intended destination) may have been lighter than hoped, as it had a cap of 21 on the number of avatars allowed into it, and a number of people did report they were unable to teleport-in as a result (there were probably around 40-50 listed on the IRC chat page).

Pile-on Test Medal

Overall the tests made for a fun social gathering, with a lot of good humour all around, and Oskar and his team apparently gathering the data they wanted.

Hopefully, there will be further follow-up on the overall intent of the tests and the results in an upcoming Sim / Server UG meeting. Oskar certainly appeared pleased with the outcome, and was on the main grid after the tests to hand out medals to the participants (providing they knew the sekrit password! 🙂 ).

 * With thanks to DD Ra for pointing this out; I missed checking the creator details earlier.


SL projects update week 41 / 2

This item is a follow-on from part one, published earlier this week.

More Server News

At the Thursday Beta Grid User Group meeting (Thursday October 11th), and prior to the network optimisation tests, Oskar gave further news in the  serve deploys for week 41. On Tuesday 9th October, the main channel received code previously on BlueSteel, which in keeping with Simon Linden’s comments at the Monday Sim / Server UG meeting, Oskar referred to as being, “A pretty small release, just some server crash mode fixes; stability ++.”

On Wednesday October 10th, BlueSteel and LeTigre received a fix to some database queries that were really slow when accessing really large groups (note these were not Baker Linden’s Group Services code, that is being looked at as a deployment in week 42).

Monday 16th October may see some restarts on the grid in order to shuffle some regions onto new hardware, with the servers having more and faster CPU cores, which will increase the number of simulators running on the new servers, but they’ll be running on faster CPU cores.

Interest Lists and Object Caching

The short-version update for this comes from Andrew Linden, speaking at the Server Group meeting on Friday 12th October, “I thought I’d have something working this week… it isn’t quite working right. You can see it not working on Ahern on Aditi…” (!)

Interest list changes: easing the pain of random rezzing

He went on more seriously to explain that while the new code is working correctly for the most part, and that rezzing orders should be improved / faster, there are some problems with objects which should be in view of an avatar not showing up and a major issue around teleporting into high ground.

When the latter happens, you effectively arrive “underground” (presumably at the default “ground level” for the simulator  – 21 metres in the case of unterraformed land). The simulator then calculates where you should be and moves your avatar appropriately. With the new code, this has the effect of breaking the server’s notion of the camera – where it is and what it can see – which is used to figure out what objects to send to the viewer. This means that the camera itself cannot be moved or updated.

There have been some performance tests on an older version of the code, which have been mixed, as Andrew also explained, “here were two performance tests run on an earlier version. One test (mostly empty region with about 30 avatars running around) showed a slight decrease in performance… about 5% worse. Another test (crowd of avatars NOT looking at a pile of dynamic objects behind them) showed about 40% improvement (less time spent running the interest list). So I went back to the code to try to fix the first test, and I think I’ve got something that will be as good or better all around.”

The code will also see changes as to how the camera behaves and in the resultant level of detail. Andrew is currently working on limiting the distance the camera cam be moved away from the avatar. Note this is not limiting Draw Distance, but limiting the distance the camera can be freely moved independently of the avatar. He’s considering 128 metres to be the likely range. There are two reasons for this.One is to prevent the camera wandering into regions which are more than one neighbouring region away, the other is because as the camera moves laterally, detail levels degrade, because object detail is tied to the avatar’s position (hence why, when you zoom a great distance, buildings and objects may only appear to partially rez, etc.). Under the new system, object detail will be tied to the camera, so that little degradation is experienced. However, in order for this to work, the camera must be kept within a reasonable distance of the avatar; if it is moved too far, the detail will start to degrade once more (presumably because of the volume of data the viewer is trying to handle).

Mesh Deformer

On Thursday 11th October at the Open/Dev meeting, Darien Caldwell outlined her ideas for using base shape info exported from Second Life when uploading rigged meshes.

If this works, it will essentially mean that rather than being restricted to using a default base female or male shape when uploading rigged meshes, creators will be able to download a human shape as an XML file (permissions allowing), and then specify this shape when uploading rigged meshes.  The basic code for handling the upload with specific avatar shape information has already been added to the deformer by Qarl Fizz, so Darien is focusing on the best way to use it, her work going into a fork of the existing Mesh Defromer project viewer.

Avatar shapes can currently be exported from a viewer via DEVELOP -> AVATAR -> APPEARANCE TO XML (again subject to the permissions system). This saves the avatar shape data as an XML file, which contains the settings from the appearance sliders, and which is automatically saved to your computer (generally to  C:\Users[USERNAME]\AppData\Roaming\SecondLife\user_settings for Windows).

To associate an avatar shape .XML file with a mesh, Darien is proposing a further revision to the mesh uploader floater, and has provided an early mock-up as to how it might look.

New option to associate an avatar shape XML file with a mesh on upload (image courtesy of Darien Caldwell)

More work is required the flesh-out this idea, including, as Oz noted at the Open/Dev meeting, making the shape export option more obvious for people to use, which will more than likely see it moved out of the Develop menu, wherein it is currently nested. The .XML file itself is not suitable for use directly in most 3D modelling programmes, so how the exported data might be used with these when creating mesh items remains to be seen. nevertheless, if successful, Darien’s approach may offer a more fine-tuned solution to developing mesh clothing to a range of shapes.

Other items

Viewer and FMOD

The use of FMOD has been the subject of much discussion within the TPV/Dev meetings of late. FMOD is used within the sound system for the Viewer, and until now, Linden Lab has provided a script which pulls library files from an FMOD repository for use in viewer builds. However, following what appears to have been a clean-up of their archives, FMOD have removed the some of the legacy files required for this, as reported in JIRA OPEN-150.

Some viewer developers have already started using FMODex within their builds (e.g Singularity 1.7.0+), which also addresses issues with sound quality as well. Other TPVs are looking at possibly integrating this work into their builds.

It currently appears as though Linden Lab themselves are looking to integrate FMODex, as they see this very much as something which needs to be addressed. Speaking at the TPV/Dev meeting on Friday 5th October, Oz Linden stated: “I got around to forwarding the JIRA on that to our engineering manager for Second Life, and he agreed with me that it is something we should definitely do something about. I’m not sure what the time-table on that will be, it’s going to go into the hopper for the next ‘Things we should do something about, what priority are they compared to all the other things we should do something about’ meeting, which happens weekly.” While openAL has also been suggested as an alternative, it does seem more likely that FMODex will be adopted, something which was hinted at by Oz when talking at the Open/Dev meeting on Thursday 11th October.

Teleport Timeouts

Baker Linden has been looking into the issue of teleport timeouts, and has managed to pin down one cause as a reproducible bug. He’s not sure as to whether it can be fixed, and is currently investigating further as to why it is happening.