SL projects news week 44/2: server, group services, mesh and more

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Server Updates

Deployments this week are being delayed some 24 hours, which means the main channel deployment will not take place until Wednesday 31st October, and the RX channels on Thursday November 1st. This has led to concerns that the main channel deployment / restarts may impact any Halloween events taking place across the grid on Wednesday 31st. Simon Linden promised to raise the concerns at an internal LL meeting taking place later on the 30th October, however, at the time of writing, the Grid Status page reports that the deployment will go ahead, starting at 05:00 SLT on the 31st.

In the meantime, the deployments for the week remain largely as previously indicated:

  • The main channel should receive the code currently on BlueSteel and Magnum. As mentioned above, the code has no externally visible changes but has some system level adjustments – release notes
  • LeTigre will receive a further update for the code currently running on it, which will include a number of bug fixes and pathfinding updates – release notes
  • On Friday 26th October, Simon Linden indicated to me that Magnum should be receiving the code planned for week 43 (the llSensor() problem has been fixed) which will include Baker Linden’s Group Services code currently on Snack, however, as of the Simulator User Group meeting on the 30th October, the final release notes for Magnum had yet to be published, so the update may still be in a state of flux
  • BlueSteel should get the same code as is on LeTigre.

Interest List

Andrew Linden has fixed a bug wherein some child prims in linkset fail to rez and he has carried out further work on performance issue he reported last time. This turned out to be an issue with the code which caused the simulator to send a full update of everything within view to the viewer each time an avatar within visual range moved. Understandably, on  crowded regions, this led to performance issues.

The code is in the process of being revised to ensure it only calls for “terse” updates to be sent to the viewer, which will help ensure more relevant information is sent to viewers when updating, which should reduce the performance hits.

Group Services

Baker Linden, speaking at the Simulator User Group on Tuesday 29th October, said that the server-side code for this project, which should improve the load times and editing abilities for very large group lists, seems to be working “moderately well” since the deployment to the Snack RC channel last week. However, some bugs have been found, Commenting on these, Baker explained that, “The group name, description, and other things don’t load right now on the Snack RCs.” However, the bugs have been investigated and fixes found, which should be merged into the code ahead of the planned deployments on Thursday November 1st. The fixes have also been tested on Aditi, where they’ve been found to induce a slight lag on group loading.

For the time being, testing this now code continues to require a dedicated SL project viewer (available for Windows, Mac and Linux), until such time as issues with the SL beta viewer code can be fixed and merges with viewer project code resumed / made available to TPV for integration.

Avatar Baking

Work is still progressing, Nyx Linden confirmed, talking at the content Creation User Group on Monday 28th October. How far down the road the work is, is unclear. The server-side of things will apparently be using the code being developed for the viewer, and it is this which is the focus of attention for the present, as has been the case for some time.In talking to TPV developers on the subject the last time the matter came up, Oz Linden confirmed LL’s plan is still to give TPVs “at least” 2 months (eight weeks) notice prior to anything being rolled out for testing, in order to give TPVs sufficient time to incorporate the code into project viewers of their own and assist with the overall testing.

SL Issues

Mesh Alpha Issue

Theresa Tennyson demonstrates the skinned mesh / alpha issue

Also during the Content Creation meeting, a problem with alpha textures as applied to worn skinned meshes was brought up. Theresa Tennyson demonstrated the issue during the meeting, which somewhat resembles the old invisiprim  / alpha issue.

Siana Gearz suggested two possible causes for the issue, “[The] first is that rigged mesh transparent surfaces appear to be drawn before prim transparent surfaces. [The] second issue is that the shader apparently writes depth for whole fragment, not just for relatively in transparent pixels.”

Nyx Linden requested a JIRA item be raised for the issue, again highlighting the problem with the recent JIRA changes, in that outside of those with access privileges to the new system, no-one could actually confirm if a JIRA had already been raised.

ETA 31st October: Seems a public JIRA on the matter is available – see MartinRJ’s comments which follow this article. Many thanks, Martin!

With thanks to Theresa Tennyson for the Simulator UG meeting transcript

SL projects update week 42 / 1

Server Updates

The main channel deployment took place as planned on Tuesday 16th October. As previously indicated, this was the code deployed to the BlueSteel RC channel in week 41 (essentially an improved database query that should help with the back-end system load).

Of the Release Candidate channels, these are due to be updated on Wednesday 17th October as follows:

  • Magnum – will not receive an update, but will continue to run with the code deployed in week 41, probably in the same configuration
  • BlueSteel – will get code that’s almost the same as the main channel, with some OS-level configuration changes that shouldn’t be visible to anyone
  • LeTigre – will be getting a minor update to the Havok library which is mostly about getting our servers to build under Visual Studio 2010 on Windows and autobuild on Linux.

The LeTigre update will use “slightly newer” versions of the Havok libraries, so concerns were raised at the Server  / Sim meeting on Tuesday 16th October as to whether this may lead to a resumption of the problem with mesh vehicles being unable to travel between regions running different versions of Havok.Andrew Linden confirmed this might well be the case for mesh vehicles moving between LeTigre regions and other regions following the deployment.

To help reduce issues with situations like this arise, it was suggested that areas such as the Blake Sea regions are either removed from the RC channels, or placed on the same channel. While this would not solve the problem grid-wide, it would reduce the impact somewhat for people using mesh vehicles in these regions. A query was put to the LL deployment team on this by Andrew Linden, and they  agreed to try to make the Blake Sea regions more homogenous by ensuring they are all on the same channel.

SL Viewer

A further stability test build for the beta viewer was made on Friday October 12th, and reached the download page on Tuesday 16th (3.4.1.265898release notes) after being cleared by QA. This should be the last stability test release and should see the OK for code merges to resume. Merges and release priorities are still being looked at, and speaking at the Open Dev meeting on Monday 15th October, Oz indicated that there are “a few open source contributions in the pipeline that are in the mix”, as well as the anticipated LL merges such as the Steam code, Monty Linden’s HTTP library updates, Baker Linden’s Group Services project code, Apple OSX Mountain Lion support (including gatekeeper compatibility), etc.

Kelly Linden reports fixing SVC-7870 (Edit Linked Parts isn’t returning creator/owner), but given the current backlog, it may be a while before this makes it through to a beta  / release viewer.

Avatar Baking

The aim of this work (Project Sunshine) is to improve issues around avatar baking and to eliminate bake fail issues. It will primarily focus on moving the emphasis for the baking process from the viewer to a new Texture Compositing server. The viewer will retain some elements involved in avatar baking – the actual baking of the avatar shape (i.e. shape values and IDs) will still take place on the viewer side, for example.

As of Monday 15th October, no major news. Commenting at the Content Creation / Mesh Import meeting, Nyx Linden said, “Still plugging along at it :). It’s a complex project with many moving pieces, we’ll let you know when there are updates, and I will definitely be asking for beta testers here when we’re ready for feedback”.

Interest Lists and Object Caching

The focus of this project is to optimise the data being sent to the viewer, information already cached on the viewer and the manner in which that data is used in order to ensure it is used more efficiently so that things rez both faster and in a more orderly manner than is currently the case.

Interest lists and object rezzing: ironing-out the bugs, wherever they are

Andrew Linden continues to iron-out the bugs in the interests lists project, including one in the main viewer codebase wherein after crossing a region boundary the connection to the region you were just in will get reset after about 60 seconds. This is impacting the interest lists work and requires resolving, so Andrew is currently focused on trying to sort it out. A problem has also been reported with objects rezzing in the test regions on Aditi (e.g. Ahern) when moving through them in a vehicle, and will be looked into.

Pathfinding

A question was raised at the Content Creation / Mesh Import meeting on the 15th October as to why a 1-prim pathfinding character  has a land impact of 15. The reason for this is due to the increase physics load on the character. As previously covered, while this may seem harsh, it actually means that characters with a much higher prim count will also have a land impact of 15 (for example, a 30-prim character will still only have a land impact of 15), unless other factors (such as streaming cost) come into effect.

There are a couple of other issues with pathfinding characters which are being (or are about to be) looking at:

  • A bug whereby copies of single-prim characters only have a land impact of one (not 15). This problem is being addressed under PATHBUG-194.
  • A problem wherebypathfinding characters suddenly appear to “fly away” when adjusting your camera position, almost as if they are suffering from lag, and then reappearing there they should actually be (I gather this tends to happen when looking at a pathfinding character, which is following a set path then turning the camera away and then back again). Andrew Linden believes the problem is related to interest list updates, and will be looking into it.

Mesh

The patch to enhance the mesh uploader when dealing with rigged mesh items was discussed at the Content Creation Mesh Import group meeting on October 15th, with Nyx expressing interest in the idea, and agreeing with a suggestion that the patch needs to be formally submitted to LL’s bit bucket repo applied to a cloned version of the development viewer, supported by a JIRA outlining the patch and with a link to the repro.

Mesh uploda enhancement: suggested that it is submitted as a patch to LL

SH-3055 is a bug relating to mesh uploads which has been around for a while, but which appears to be affecting more people of late. With it, mesh uploads fail without any error message or warning on clicking CALCULATE or UPLOAD on the mesh upload floater. The issue is hard to track down (or even reproduce) as it doesn’t occur with any consistency. Either the upload works, or it simply sits as if waiting for something – whether it is waiting for data to be returned by the server, or whether it is receiving information and failing to action upon it.

Darien Caldwell and Nicky Dasmijn have been working with a debug viewer in an attempt to pin the problem down, but so far without success. One school of thought they are pursuing is that it is a problem with the viewer’s cURL wrapper (which is also thought to have been responsible for the recent crash issues being experienced in the beta viewer). The thinking behind this is that the problem appeared to come about with the introduction of a multi-threaded cURL in v3.2.5 of the viewer – with 3.2.4 having exhibited no major issues with uploading.Nyx Linden has stated he’ll take the problem to the team work on cURL to see if they can identify anything.

Materials Processing

No further updates. When talking to Geenz Spad and Oz Linden on Tuesday 16th October, Geenz could only say, “There’s not much to really report on materials for the time being unfortunately, but when there is something I’ll be more than happy to tell everyone.” Oz then added, “We’ll do more than tell you – we’ll give you something to play with :-)”.

Network Pile-on Test Update

Commenting on the thread for the pile-on test, Oskar Linden said: “All of the tests passed and the code will be going to RC next week. Thank you all for your help!”

With thanks to Baz deSantis for information on the Sim / server Group meeting.

SL projects update week 40 / 2

Server Deploys

As many are aware, there was a major error in this week’s LeTigre Release Channel deploy. Apparently, the root cause of the problem lay in the server-side prim account code, which Simon Linden describes as having “blown up” on the LeTigre RC channel. This resulted in a large number of items (including partial builds) being returned to people’s inventories as a result of regions being seen as “full”. The problem required a two-stage recovery:

  • LeTigre regions were rolled back to a state prior to the faulty deployment, and were then updated with the BlueSteel code also deployed on Wednesday October 3rd. This helped to determine the extent of the damage (a total of some 1200 regions)
  • The regions damaged by the land impact miscalculation were then restore to a state prior to the roll-out of the original faulty LeTigre code. These had to be restored manually, which took a considerable time

There is further post-mortem work going to to try and discover why this error did not reveal itself when the code deployed to LeTigre was being tested on Aditi, and whether there is anything specific to the regions impacted by the error which may have triggered it. Thought is now also being given to managing large scale region restorations, despite this being the first time there has been such a massive issue of this kind occurring across the grid.

Current RC plans for next week call for the same maintenance release to be made to all three RC channels, which Simon Linden describes as, “Mostly internal changes but [which] does include a minor update for the physics engine library … It’s almost all updating libraries … we’ve been using a fairly old set of compilers and such to make some of the development builds of the servers, and this brings us to more recent code.” Further details on the deploy should be available next week in the Second Life Server section of the Technology forum.

SL Viewer

As indicated in part one of this report earlier this week, problems have continued with the Beta viewer code and high crash rates. Work has been ongoing to try and locate the probable cause(s), some of which included the temporary return of tcmalloc. While not actually a cause of the crash issues, having tcmalloc disabled was affecting efforts to reproduce the problems. a beta release was made on the 3rd/4th October (3.4.1.265434), which is proving to be a lot more stable than previous versions, and which happens to have tcmalloc enabled.

The current plan is for a further beta release to be made, most likely on Monday 8th October, which should see tcmalloc turned off once more (if not removed). Should this also prove to be stable, the fixes it contains will be merged back into the development viewer code, and this will clear the way for clearing the backlog of code merges for both the beta and development viewers. It may also see a further 3.4.1 release version of the viewer being made.

Among the projects awaiting merging into the development and beta viewer code are:

  • The Steam support changes, which have been available within a development viewer stream, and which are described as “mostly cosmetic”. There is apparently a version of the viewer on Steam, but it is not available for general viewing / download, and is presumably there for testing purposes
  • Monty Linden’s HTTP library (texture fetch) code
  • Baker Linden’s Group Services project code
  • Apple OSX 10.8 Mountain Lion support work, including gatekeeper compatibility
  • Bug fixes and further regionalisation work.

Previous plans for these releases called for them to be made under the 3.4.2 code base. While this wasn’t discussed at the TPV/Dev meeting, one assumes this is still the case. However, speaking at the TPV Dev meeting on Friday October 5th, Oz Linden indicated that the order, etc., in which waiting merges will be cleared hasn’t been fully defined, and will be the subject of internal conversations next week at the Lab.

Avatar Baking Project

Bake fail: a familiar problem for many

There is still no major news on this project, although work is continuing both on the viewer and on the server code.

The plan remains to provide TPV developers with access to the viewer code at least 8 weeks ahead of any initial deployment of the server-side code to an Agni release channel. This is to allow TPVs time to merge the code into their viewers and participate in ongoing testing of the new service.There is a possibility that that viewer code will be available sufficiently well ahead of things in order for TPVs to be able to use it alongside the testing on Aditi (beta grid), depending on the status of the beta grid tests and how development of the viewer code progresses.

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SL viewer and project mini-update

A couple of items came up at the Open Dev meeting held last night (Thursday 27th September) which are worth pushing out by way of updates to my SL Projects Update from earlier in the week.

Beta Viewer

The beta release ((3.4.1.265134) made available on September 24th is still suffering from high crash rates. Whether these are related to memory leaks or not is currently unclear, as the Lab is apparently having trouble reproducing specific causes of crashes. It is believed that tcmalloc is no longer a part of the code. As a result of the investigations, the planned frequent deploys of 3.4.1 beta releases as specified by Oz last week has been delayed. This is liable to have a knock-on effect with planning for the 3.4.2 beta releases as well, although 3.4.2 continues to roll to the development branch, with 3.4.2.265141, released on the 25th September being the current development build at the time of writing.

Mesh Deformer

Following the release of version 3.4.1.265139 on September 25th, the Mesh Deformer project viewer updated to 3.4.1.265192 on September 26th. This version has the normals calculation disabled, as it conflicted with how Blender creates sharp edges and would cause the deformer to split the edge. In addition, it appears from comments made at the Open Dev meeting that meshes uploaded prior to this version will not deform unless worn with a mesh uploaded using this version, which is intentional.

There have been further contributions to the test clothing at Hippotropolis, and Nalates Uirriah commented that some creators are placing free copies of clothing for testing up on the SL Marketplace for people to use in tests. Oz requested that anyone doing this to please explicitly state the version number of the project viewer they used to upload the mesh clothing.

At the moment, and based on contributions received, Oz is hoping to arrange for a new series of tests to be run to test the overall functionality for the deformer as it stands. Again, if you do wish to contribute clothing (uploaded using the current version of the project viewer), please refer to Oz’s original request on the subject.

Avatar Baking

Bake fail: a familiar problem for many

Avatar baking is progressing, although there is still no time-frame for any project viewer or roll-out of code on the server-side.

Currently, work is being undertaken to move the viewer’s baking code to its own library, which will be used with the new server-side baking service as well. Thus the same code will be used when changing your appearance locally, and to send your updated appearance out via the new baking service, once it has received the updates from your viewer. This aim of this work is to further eliminate some of the errors which can occur as a result of the current baking process being reliant upon viewer-side hardware, drivers, etc., wherein the same inputs can lead to different results when using different hardware.

One of the biggest benefits of this work will be removing the burden of texture caching from the simulators. With the new system, avatar texture caching will essentially be a global service: the Texture Compositing service becomes a single point-of call for avatar texture information, instead of a simulator having to contact the simulator a visiting avatar was originally baked on in order to obtain texture data.

This not only means that texture caching will be removed from the simulators once the new service is up and running smoothly, it could pave the way for other benefits as well, as Oz mentioned in the meeting, “In theory at least, that lets us introduce persistent connections and pipelined requests (don’t know if that will be in the first version or not), which could enormously speed up getting the bakes when you enter a crowded area.”

Plans for the project remain aimed towards providing TPV developers with as much advanced warning as possible prior to the new service being enabled on the main grid (Oz has been aiming at around two months’ notice), to give them time to incorporate the viewer-side code changes and assist with testing the new service. When the server-side code is ready, a project viewer will be released, and a series of regions on Aditi (the beta grid) will be updated to use the new service for testing purposes.

I have a more explicit explanation of the core aims of the new avatar baking service available in an overview of the Shining project.

Related Links

SL projects update, September 26th

Update 28th September: Please also refer to an update post on some of the projects / news given here.

SL Viewer Status Updates

Linden Lab have been working hard on a range of viewer-related issues, notably crash rates and memory leaks, which have slowed the viewer update a release process up over the last few weeks. In terms of memory leaks, tcmalloc has been identified as the culprit, with Linden Lab deciding that dropping it is “probably a good idea”, according to Oz (tcmalloc has previously been implicated in crashes linked to the use of things like Microsoft’s Skydrive). There have also been an issues with LL’s statistics system which have meant that the viewer hasn’t necessarily been accurately tracked in terms of crash rates, etc.

Beta Releases

As it stands, LL hope to have the blocks on the various code merges removed during this week, which should see a rapid series of beta releases coming down the pipe. This work commenced with an initial 3.4.1 beta release (3.4.1.265134) emerging on September 24th. It will be followed by around three or so additional and rapid 3.4.1 build iterations aimed at confirming the viewer’s stability and at replacing various fixes which had previously been removed from the viewer code while trying to identify the causes for the viewer crashing / suffering memory leaks. It is expected that each of these iterations will be on the beta release build channel for a couple of days, prior to being replaced. Following these there will be a series of project updates, the first of which gatekeeper compliance project, which is also targeted for a 3.4.1 release build.

Project-related Releases

Once the stability of the beta viewer has been confirmed, it is anticipated that project-related code will be merged into the viewer, most likely starting with 3.4.2 builds. Among the releases planned for 3.4.2 is Monty Linden’s HTTP Library Services and Baker Linden’s Group Services code. These are currently targeted to reach the beta build channel in week 40 (week commencing Monday October 5th).

These releases will at some point include the Steam updates currently in a Development branch as well, which might in turn mean that Second Life could be ready to appear on Steam in the very near future, once these updates have reached a release version of the viewer.

Account creation prompt: heading for the beta viewer

Group Services Project

The Group Services project is an attempt to improve the management and editing of large SL groups by replacing the current UDP-based service (which has capacity issues with the size of group lists it can comfortably handle) with a new HTTP-based service. The project viewer for this is already available (for Windows, Linux and OSX.), however, as mentioned above, the current plan is to get this into the 3.4.2 build stream alongside the HTTP textures project, possibly in week 40.

Originally, the server code for this project was due to have been rolled to the RC channels during week 38, (week commencing September 17th), but the channel deploys were postponed after QA issues were found. As a consequence, the roll-out was due to take place on Wednesday 26th September, but has again been postponed.

There has been some confusion as to the aim of this project, with some people believing it is focused on fixing group chat issues such as  lag and chat failing to start. This is not the case at all; as stated above, the project is aimed at improving the management and editing of large groups (10K+) through the use of a new HTTP service.

HTTP Library Services

As indicated above, the first phase of this work, covering a new texture fetch service, should be appearing in a 3.4.2 beta release of the viewer in the near future.

HTTP Libraries project viewer: improved texture loading and rezzing

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Upcoming SL projects update

There is a lot going on in terms of projects and development work in Second Life. The following is a further update on a number of key projects I’ve been following and reporting upon through the pages of this blog.

Group Services Project

The Group Services project is an attempt to improve the management and editing of large SL groups by replacing the current UDP-based service (which has capacity issues with the size of group lists it can comfortably handle) with a new HTTP-based service. The project viewer for this is already available (for Windows, Linux and OSX.), as I reported last week.

This week sees the server-side code rolled-out to all three RC channels (Magnum, LeTigre and BlueSteel), allowing the project viewer to be tested in handling very large groups (significantly larger than are available on Aditi). Note that those running viewers without the new code on any RC region will be unaffected, as they will continue to access the current UDP service.

There are still no timescales as to how long the testing of the service will last (“It’ll take as long as it takes,” Baker commented recently), or when the viewer code will progress beyond the project viewer. However, a number of things should be noted in reference to the eventual roll-out:

  • The viewer code is not being made back-compatible with V1 code by the Lab. Therefore, TPV developers using the V1 code base will have to backport the code themselves in order to use the new service
  • The initial HTTP service roll-out does not include any data compression. This means there will still be some delay in downloading member lists for very large groups with tens of thousands of members
  • Once the new service is rolled-out, which service is used is entirely transparent to the user. If a viewer with the new code is running on a region which has the server-side HTTP service, it will connect to that service. If it is on a region using the older UDP service, it will connect to that service instead
  • Once the HTTP service is fully deployed, viewers which do not implement the viewer-side code will still be able to access groups with member lists up to 10K in size via the UDP service until such time as it is switched off (which will not occur for some time after the HTTP service has been rolled-out). However, attempts to access groups with lists larger than 10K will fail.

Interest Lists and Object Caching

It’s been a while since I’ve reported on Interest Lists Object Caching, which forms a part of the Shining Project.

To recap: when you enter a region at the moment, your viewer receives a huge amount of information on what requires updating, much of it relating to things you can’t even see from your position in the region. This information is received in no particular order, with the familiar result that things appear to rez in your view in a totally random order. Not only that, but the chances are that if you’ve previously visited the region, much of the information being sent to your viewer is already locally cached – but is being ignored. The focus of this project is to both optimise the data being sent to the viewer and the information already cached on the viewer with the aim of significantly improving object rezzing times in terms of speed and order (so objects closer to you rez before those further away, for examples).

Object caching and interest list changes: easing the pain of random rezzing

Andrew Linden had hoped the project would be going to QA this week ready for roll-out to one or more RC channels in the near future, but some last-minute problems popped-up and have delayed things until he can get them sorted out. In the meantime, the code has been deployed to a number of regions on Aditi, and Andrew plans to, “Try to throw a pile of test avatars at it to stress it out. Later this week.” No viewer-side changes are associated with this work.

Materials Processing

Work continues on the project to bring materials processing to Second Life. Last week, it appeared as if the new materials – normal and specular maps – would have their own rotation and positioning options independent of any texture (diffuse) map. This week, it appears that this is the hoped for situation, but the matter is still open to question – which goes to show how fluid the project is.

The new capabilities require changes to the rendering pipeline, and details have been released on some of what this entails.

In order to work, normal and specular maps require what is referred to as per-pixel lighting (as noted in the original blog post on the subject). As such, there has been a debate on whether it would be better to develop a per-pixel lighting framework within the viewer, or work to make the current deferred rendering system more accessible to per-pixel lighting capabilities. As the latter approach will allow getting materials processing working within SL sooner than would otherwise be the case, it has been decided to go that route. Thus work is focused on making the current lighting system more configurable and able to better handle a broad range of material types (metallic, matte, plastic, etc.), together with adding support for both per-object and per material shading differences.

However, a dedicated per-pixel lighting framework does offer advantages of its own, and as such is being considered as a possible future extension to the project, which may be implemented at some point down the road. One such advantage is that could potentially be run in a non-deferred mode, which might lightening the load on older graphics systems.

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