The main cause of the issues experienced by mesh vehicles, Oskar and Maestro Linden explained at the Server Beta meeting, is that Havok doesn’t concern itself with back compatibility and outside of Second Life, it has no requirement to do so. “We use Havok in ways Havok was never intended to work,” Oaskar commented. “Havok was created for single version offline games, Like Call of Duty or something. In a game like that there is only one version. It [Havok] wasn’t built for a perpetual virtual world like SL that can have different versions of the same thing next to each other. We really push the limits of what Havok can do so I can’t really blame them. SL is very unique in a lot of ways.”
Commenting on the optimisations in the LeTigre Havok code, and responding to concerns things might get worse for vehicles, Maestro said, “On the contrary, it should be slightly smoother. A lot of the bumpiness is from the terrain shape being too complicated, extra triangles where you don’t really need them. With this change, it first generates the same collision mesh, then simplifies that mesh to have fewer triangles”.
However, if region owners / estate managers believe the change is having a negative impact on their regions, the optimisation can be disabled using the Region Debug Console command “set optimize_terrain false”.
As it is, the deployment revealed some LeTigre regions entered a crash loop situation, so deployment of the LeTigre update to the rest of the grid may be delayed while the reasons for this are investigated.
Upcoming Deployments for Week 43
At the Friday Simulator User Group meeting on the 19th October, Simon Linden indicated the deployments planned for Tuesday 23rd and Wednesday 24th October comprise:
- On Tuesday 23rd, the main channel should be updated with the code currently on the Magnum RC which are intended to “make things run better on new hardware”
- On Wednesday 24th, the Magnum channel should receive bug fixes together with Baker Linden’s Group Services project code (the viewer side of which is still blocked)
- Also on Wednesday 24th, LeTigre should receive further updates for the new Havok code (which presumably include fixes for the crash loop situation Maestro reported in the Server Beta UG meeting (see above)
- And again on Wednesday 24th, BlueSteel should receive, “Some more invisible changes that should help us deal with some problems like full disks that make servers very unhappy”
Some of the code being deployed into the RC channels relates to new hardware. Furthermore, on Monday 15th October there were region restarts connected to new hardware of some description. This has led to questions being asked about the hardware the Lab is apparently deploying. At the Beta Server UG meeting, Oskar could only say in reply to questions, “I’m not allowed to talk about hardware specifics, sorry.” Andrew Linden, speaking at the Simulator User Group on Friday 19th October, was a little more forthcoming, without giving much away, “We do have some hardware upgrades in the works. I don’t know much about it, but one of the ‘helps with backend issues’ server upgrades that either just went out, or is going out soon, is part of that effort.”
Linden Lab has tended to keep quiet on hardware for a while now, so the reticence to speak is not surprising. It is also not entirely clear where the new hardware is going, although the fact that simulator code is being deployed to ensure regions “make better use of new hardware” suggests some will be use for running regions. Whether this means the hardware will have more cores (so more regions per server) or faster clock speeds (so better performance) or both (most likely), is something the Lab are keeping to themselves.
A Little More on Interest Lists
Andrew Linden continues to chip away at Interest Lists, fixing his code and is getting to the point of “seeing the light at the end of the tunnel. The issue of now seeing things when moving through a region in vehicle appears to be resolved, and Theresa Tennyson reported she is no longer crashing into invisible buildings any more – the result, apparently, of Andrew coding a wrong call in the new code. Other issues remain, but overall things are starting to look better.
Teleport Timeout and Region Crossings
Baker Linden reported to the Friday Sim / Server User Group that he’d completed his investigations into teleport timeouts. “Another Linden was working on multithreading region crossing,” he stated, “And his new code disables the offending code which (I think) is the main cause of timeouts when teleporting. Once that code gets in, I’m hoping we’ll see a decrease in the amount of timeouts while teleporting.”
When this will be is unclear, as Simon Linden commented that while the region crossing code is in QA, it is not ready for any RC channel, nor has it been deployed to Aditi.
Once the code has been deployed, there should be a noticeable reduction in the lag event felt by everyone in a region as someone crosses into a neighbouring region.
Clearly in the mood for dealing with lag issues, Baker also reported that he is now looking into object lag during rezzing to see if there is anything “blatantly obvious” which can be eliminated / changed to help reduce issues.