I missed the Simulator User Group meeting. But, I just saw the meeting minutes got posted. There are a few interesting things that came up in the meeting.

TimeWarp

This is the Linden name for the problem of simulators stalling for 30 to 60 seconds, which knocks people in the simulators’ regions offline. Since the operating system kernel upgrades on the ADITI grid that problem has disappeared.

This week, Oct 3 to 7, The Lab will be upgrading the kernel on all the servers running simulators. If I understood correctly, that upgrade will also be applied to many of the support services servers. This means the week will see lots of region restarts. See: Critical OS Software Upgrade — Region Restarts

Regions will see at least 2 restarts and if unlucky 3.

Continue reading →

Tuesday a new version of the server rolled to the main grid. Only one high priority fix made it to the main channel this week. This version contains the fix for SVC-7283 – llRemoteLoadScriptPin and llGiveInventory fail when installing non-full perm items into worn attachments.

This problem was causing the permanent loss of scripts in worn objects. As it was breaking existing content, this was a top priority to get fixed. It was considered enough of a priority that it was placed on all three Release Channels to assure we would have a fix this week, provided the fix passed testing, it did. See Second Life Server News Week 38 for more information.

Some are upset that it took 2 weeks to roll out this fix. The plan is to test and test and be sure a fix actually fixes the problem without breaking something else. That means a week of testing in ADITI and a week of testing in a release channel. The Lindens thought this fix important enough to place it on all 3 RC’s. If it had failed it would have failed all the release channels and delayed all other fixes in progress. Their concern and urgency on this issue pushed them to use all 3 channels. But, for some that is not good enough. That’s life.

Continue reading →

There was lots of interesting news at this week’s meeting. Check these things out.

Roll Outs

Surely by now you know the main grid gets new server software Tuesday morning. The Release Channels get new software on Wednesday. This week the main grid got the the Server-Maintenance update running on Blue Steel.

Data Collection

The Lab is doing lots of analysis of the regions to find bottlenecks and problems. This roll includes new data collection features. One of the more confusing and hard to find problems is labeled TimeWarp. The Lindens think they have found the problem, at least where the problem resides. The additional data collection will provide more information on many aspects of the Second Life servers and reveal more about the TimeWarp problem (more on that later).

Unexpected Prim Return

The addition of Land Impact costs has created some surprising situations where region prim limits are hit and prims get returned. Changes made by scripts can change object shape and trigger a Land Impact value and trigger returns.  A feature has been added to the Linden Scripting Language (LSL) to anticipate such changes and prevent them. I think the idea is to return an error message in the script error channel rather than allow the change and trigger returns. Nice idea.

Continue reading →

Andrew Linden talked about caching in the 9/13 Simulator User Group. He has the job of writing code to track cache misses. I’ve never thought the viewer cache was doing much for me. I don’t see much difference in render speed for returning visits to places I’ve visited from places I’ve never been to.

The trick is figuring out which are planned or expected misses and which are cache failures. If you have been to a region you should have all the needed textures in your cache. Those textures should be found and avoid the need for a download. If the texture is in the cache and it downloads again, it can be considered a miss or failure.

Of course if you have never been to a region, one expects all the texture to have to download. So, misses are not a bad thing. The challenge is in knowing when the caching system is failing. It has broken in the past. So, the new code will be an alerting system.

The simulator has an Interest List. In the list are the things the viewer needs to render the scene for its avatar. As Andrew describes it; when an avatar arrives in a region things around them have specific positions, geometry, and textures needed to render them. The simulator figures out what objects are in the avatar’s view and assembles a list that it sends labeled with a version number. When things in the list change, a new list is sent with an updated version number.

Continue reading →

As with the Sim User Group, things are a bit mundane right now. That are a few interesting things that came up in the user meeting.

Two second lags… some people are seeing short lags where the viewer sort of freezes up. One fix that has been suggested is to change the Debug Settings value for curlUseMultipleThreads. Because of some crash issues the default value is FALSE. Some say changing this to TRUE solved the mini freeze/lag problem. Try it at your own risk.

Curl typically requires a connection for each thread, afaik. So, setting curlUseMultipleThreads true may increase your number of connections. Some user modems can only handle a limited number of NAT connections. One can try to reduce the maximum number HTTP Texture Get connections to offset the cURL increase.

One of the changes rolled to the main grid was the ability for regions to detect users with Premium Accounts. That is needed for the new enhancements to premium membership. Oskar hints that other benefits than just the two announced for premium membership are coming.

Continue reading →

Not a lot is happening in sim development right now, well … that is exciting anyway. The work of fixing bugs and tweaking performance continues and keeps Lindens busy. There are a few interesting tidbits.

The Morris region in ADITI got a new version of the LSL Optimization Project last week, week 35. Scripts should run faster there. Andrew is looking for any data people may gain experimenting with scripts there.

Andrew Linden is looking at the Lab’s auto-build service and considering how to move server development over to it and VS2010. There are advantages to using VS2010. I’m not doing any serious software application development, so I have no idea why it is better, other than the general newer is better thing.

But, there are several compile issues that will be improved by moving the server development over to the auto-build process. Things like using newer libraries and upgrading the server’s OS kernel are dependent on moving to auto-build. So, the move to VS2010 may just be a side effect.

Continue reading →