Region Crossings Revisited

[Fionalein]

There already is a zone near the border where everything is physically known by both sims. That gives you maybe a second extra when traveling slowly (10 meters per second is about 20 miles per hour), so it's limited use on a motorbike. But it's why you don't routinely crash out while walking around in the Ahern telehub.

Not everything. Maybe avatars but definatelly not everything... or we would not have to double bridges over crossings...

 

[Argent Stonecutter]

Not everything. Maybe avatars but definatelly not everything... or we would not have to double bridges over crossings...

Avatars and vehicles. I thought other physical content but I'm not sure.

 

[Chalice Yao]

The wings appear to be an attachment, and not an actual SL vehicle or stand alone object by definition.

I had specifically asked at the latest Server Group meeting if this would improve avatar region crossings, and they said it wouldn't. The way regions handle objects (vehicles) crossing regions is different than avatars crossing regions.

That kind of suprises me, really, as attachments are also purely sim-side. Mostly noticable from the fact that if you make any changes to them and the sim crashes, it's all gone unless you logged out or detached them.

And most vehicles these days have way less scripts and geometry than the average avatar - so, I am confused there.

EDIT: Although I now wonder if your attachments aren't exactly streamed like vehicles, but the avatar doesn't need to wait for them, but vice versa...

 

[Sid]

So SL will come with their first beta release any time soon now?

 

[CronoCloud Creeggan]

I can confirm, they are much improved. I took my SRSLY tricked out Bandit 460AK (additional animations, RiB, running lights) with my usual fashionista self, out for a jaunt in Bellisseria. There's a slight hitch when crossing, but nothing like it used to be. Even crossing borders in quick sucession at corners was good. I even did crossings at max speed. I'll get around to doing another jaunt in the Blake and see how that works out.

 

[Sid]

Indeed, my Unsinkable 23 (Also a 460AK) did NOT sink in the seas around Bellisseria this morning. The sim crossings are still not perfect, but improved.
Imagine how it can be in 2035 with the next overhaul.

I abandoned my houseboat a few weeks ago, frustrated about loosing my boat so often during trips.
I guess I'll go back into the waiting line for a new one. Especially since the victorian sim that I live in now in Bellisseria is totally boring.

 

[Adeon Writer]

Imagine how it can be in 2035 with the next overhaul.

EEP might be out by then. I know they were working on it when I first joined.

 

[Jopsy Pendragon]

I wonder why they can't sort of, render everything in both regions at once, during the transfer. Like when the object or Avatar is within 5-10 m of the border.

Basically, an overlapped edge of each region.

Mirroring unchanging data is easy. Mirroring an active script in a physical object is... hard. Even a slight delay could cause them to get out of sync.

The problem is that scripts run in the region server, and the changing data needs to be 'frozen' and 'handed over' to the next region. I suppose it could be possible to re-architect everything so that moving scripts were run in a non-region server cloud that talked to regions, but it would likely result in an astronomical increase in network traffic. Everything is a compromise.

 

[Khamon]

What Jopsy Said

One reasonable solution might be to provide larger sims for seas and racetracks and high speed fly zones and sandboxes. That’s the ticket. Someone should’ve suggested that to Linden Lab along the way.

 

[Fionalein]

One reasonable solution might be to provide larger sims for seas and racetracks and high speed fly zones and sandboxes. That’s the ticket. Someone should’ve suggested that to Linden Lab along the way.

AFAIK it often has been asked for...

 

[Argent Stonecutter]

Mirroring unchanging data is easy. Mirroring an active script in a physical object is... hard. Even a slight delay could cause them to get out of sync.

You can start the lengthy process of cloning the execution state without waiting for the crossing to be committed (I don't know whether they do this), and keep running the code on the old sim (within the zone) until the handover is complete (they do this).

You can see the latter by walking off the edge of the sim into the void. There's a narrow zone of the void where you can actually stand because the sim is still maintaining your avatar in the zone.

 

[Jopsy Pendragon]

You can start the lengthy process of cloning the execution state without waiting for the crossing to be committed (I don't know whether they do this), and keep running the code on the old sim (within the zone) until the handover is complete (they do this).

You can see the latter by walking off the edge of the sim into the void. There's a narrow zone of the void where you can actually stand because the sim is still maintaining your avatar in the zone.

Either they're freezing and sending the entire dynamic script state at once, or they're doing something I don't want to think about with snapshots and delta checkpoints, and reconciling them in the destination region. *shudder* Not inconceivable, but not something I'd ever have any interest in attempting to code.

 

[Argent Stonecutter]

For the old LSO based code, they just copy the raw data block. It's one simple and fast operation, basically downloading a 16k file.

For the Mono code, they stop the running code, walk the tree, and marshall it into a package and unpack it on the other side. Then they have to run a JIT compiler over the code to reproduce the native code that actually runs. This used to be all done in one operation which is why teleporting and region copying mono scripts was such a load on the sim. I don't remember all the optimizations they've made on this process, but I would definitely describe it as something I'd have no interest in attempting to code.

 

[Chalice Yao]

Either they're freezing and sending the entire dynamic script state at once, or they're doing something I don't want to think about with snapshots and delta checkpoints, and reconciling them in the destination region. *shudder*

Acaaaaatually.....
It's along those lines how live migrations of the running RAM of entire Virtual Machines gets copied between cluster nodes in, say, Hyper-V and VMWare. You know, where you have an *entire OS and application* running while it all gets migrated between two physical host machines without downtime or interruption.

....yeah, it's one of the things that still kinda has me in absolute awe.

 

[Jopsy Pendragon]

Acaaaaatually.....
It's along those lines how live migrations of the running RAM of entire Virtual Machines gets copied between cluster nodes in, say, Hyper-V and VMWare. You know, where you have an *entire OS and application* running while it all gets migrated between two physical host machines without downtime or interruption.

....yeah, it's one of the things that still kinda has me in absolute awe.

What gives me the gibbering horrors, is the idea of -adding- that capability to third party technologies that were integrated into your product. I expect that kind of magic from VMWare, they've got the economy of scale to actually bring talent together to create stuff like that. And I imagine it's easier to accomplish when your field is 'closer to the hardware'. Well, when compared to emulating someone else's operating system at least.

But LL tends to stay higher up the protocol stack so re-engineering that functionality for a special case in someone else's code.... ugh... every update must be a living horror of testing to make sure SL-specific modifications don't start intermitantly having problems.