User:Babbage Linden/Office Hours/2008 11 12

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Transcript of Babbage Linden's office hours:

[8:16] Nock Forager: Hi Babbage fallin

[8:16] Babbage Linden: hi everyone

[8:16] Babbage Linden: sorry i'm late

[8:16] Imaze Rhiano: hi

[8:16] Fake Fitzgerald: hi

[8:16] Babbage Linden: stuck in a meeting

[8:16] Babbage Linden: let me ping the lists

[8:16] WolfPup Lowenhar: that is ok

[8:17] Imaze Rhiano: Arawn... move bit - let Babbage to sit his throne chair :P

[8:17] Chaley May: hi

[8:17] Arawn Spitteler: Your heart is mechanical, so you must nly be tardy

[8:18] WolfPup Lowenhar: hey sheet

[8:18] Sheet Spotter: G'day, eh.

[8:18] Babbage Linden: thanks arawn :-)

[8:19] Babbage Linden: so, we haven't been working on any specific scripting tasks this week

[8:19] Babbage Linden: but there has been more discussion about script limits for open spaces

[8:19] Babbage Linden: and we've also been talking about embedding mono in the viewer for scripting

[8:20] Babbage Linden: and we've built a proof of concept viewer which embeds mono and iron python

[8:20] Babbage Linden: which has been interesting

[8:20] Babbage Linden: we've got a meeting at 9 to talk about whether we want to take that forward

[8:20] Babbage Linden: the initial goal will be to use it for automating testing

[8:21] Babbage Linden: but ultimately it would be nice if we could also use it for resident scripting

[8:21] Chaley May: err it dont work like that

[8:21] Chaley May: oops wrong chat

[8:21] Sheet Spotter: Are there any plans to show an AV the scripting impact they have on a sim?

[8:21] Joshewa Daniels: we need a way to get useable websites on prims interactive abilitys, i know it will work i have seen it in other 3d world games

[8:21] Babbage Linden: sheet, good question

[8:21] WolfPup Lowenhar: that is already built into the virewer

[8:22] Sheet Spotter: Similar to Avatar Rendering Cost, but focussed on the load their scripts are creating.

[8:22] Babbage Linden: for the script limits work, we're creating parcel and avatar pools for script resources

[8:22] Joshewa Daniels: really need better parcel prim limits as well

[8:22] Joshewa Daniels: thats something that has been needed for a long time

[8:23] Joshewa Daniels: and i know 98% of all us members would agree

[8:23] Babbage Linden: there will be ll* library calls for scripts to find out the used and available script resources in the current pool

[8:23] WolfPup Lowenhar: kewl

[8:23] Babbage Linden: so you will be able to attach and object which could tell you how many script resources in your pool are being used

[8:23] Babbage Linden: and are available

[8:23] Babbage Linden: we are also talking about making that visible in the ui

[8:24] Sheet Spotter: Awesome.

[8:24] Babbage Linden: but there's lots of work being done on the ui

[8:24] Sheet Spotter: Most AVs are not aware of the impact they have.

[8:24] Babbage Linden: so i'd prefer not to add more ui complexity where there are lots of people try to remove complexity

[8:24] Sheet Spotter: If they were aware, they might moderate their impact.

[8:24] Babbage Linden: yes, i agree

[8:24] WolfPup Lowenhar: that would help builders out cause then they could better script there items to use less of the pool

[8:24] Babbage Linden: making people aware of their impact would help

[8:25] Babbage Linden: we are likely to first expose script resource usage

[8:25] Nock Forager: What "resources" parameters will be shown?

[8:25] Babbage Linden: then work on determining reasonable limits

[8:25] Babbage Linden: based on both the current script usage

[8:25] Babbage Linden: and the script usage we can support on various configurations

[8:26] Babbage Linden: full regions get around 800MB of memory for example

[8:26] Babbage Linden: for scripts, physics, updates, texture transfers and everything else

[8:26] Babbage Linden: open spaces end up with far less memory

[8:26] WolfPup Lowenhar: im alwas wondering how big an impact im having on regions with my builds

[8:26] Babbage Linden: as there are 16 sharing the same host

[8:26] Myla Moody: when you say "script usage", are you speaking of memory use, instructions per second, events, etc? :)

[8:26] Babbage Linden: i'm mostly talking about memory in the first instance

[8:27] Babbage Linden: the biggest performance problem we have is when simulator processes grow and make the host swap

[8:27] Babbage Linden: so the first resource we'll look at is memory

[8:27] Babbage Linden: CPU is somewhat self limiting

[8:27] Babbage Linden: in that we give scripts a certain number of ms to run per frame

[8:27] Babbage Linden: if all the scripts aren't run, they are run next frame

[8:28] Babbage Linden: so, running many scripts that use lots of CPU

[8:28] Babbage Linden: makes the scripts slow down

[8:28] Babbage Linden: but shouldn't make the sim slow down

[8:28] Babbage Linden: whereas many scripts causing the host to swap

[8:28] Sheet Spotter: Are sims allocated to servers based on their historical memory usage? Can low usage sims be paired with high usage sims?

[8:28] Babbage Linden: will slow the entire region down

[8:28] Babbage Linden: and all the other regions on that host

[8:29] Babbage Linden: sims are allocated based on the software installed on hosts

[8:29] Babbage Linden: so, if you've used the preview grid

[8:29] Babbage Linden: you may have noticed that you get "this simulator is running a different version" message

[8:29] Babbage Linden: where we have hetrogenous grids

[8:29] Babbage Linden: ie grids where different hosts have different software

[8:29] Sheet Spotter: That message also appears on the main grid, during rolling upates.

[8:29] Babbage Linden: het grid has been a massive success for us

[8:30] Babbage Linden: it allows us to do rolling restarts

[8:30] Babbage Linden: and test multiple versions of second life

[8:30] Babbage Linden: at the same time

[8:30] Arawn Spitteler: Before Het Grid, we'd be closed right now.

[8:30] Babbage Linden: when hosts start up

[8:30] Babbage Linden: they find regions that should be running on the software that the host has installed

[8:31] Babbage Linden: so, we don't use load to determine where regions get run

[8:31] Babbage Linden: we use the region's channel

[8:31] Babbage Linden: and find a host with that channel's software

[8:31] Babbage Linden: the biggest problem with the memory bloat due to scripts

[8:31] Babbage Linden: is that one heavily scripted region

[8:32] Sheet Spotter: Without that assessment, all the high memory usage sims could be placed on one server; all the low usage on another.

[8:32] WolfPup Lowenhar: that is an interesting approach

[8:32] Babbage Linden: can affect the performance of lightly loaded regions

[8:32] Babbage Linden: and when regions swap hosts due to restarts

[8:32] Babbage Linden: a region that ran ok last week

[8:32] Babbage Linden: might struggle this week

[8:32] Babbage Linden: when we have resource limits

[8:32] Babbage Linden: the performance should be more predictable

[8:32] Sheet Spotter: Cool.

[8:33] WolfPup Lowenhar: that makes since

[8:33] Babbage Linden: no combinations of regions should cause bad performance

[8:33] Sheet Spotter: Will the limits trigger a throttle?

[8:33] Babbage Linden: the limits will work like prim limits

[8:33] Sheet Spotter: A progressive throttle.

[8:33] WolfPup Lowenhar: and that would improve the overall SL experience

[8:33] Babbage Linden: so we don't add yet another rationing system

[8:34] Babbage Linden: if there isn't enough memory availabe

[8:34] Babbage Linden: an object won't rez

[8:34] Babbage Linden: just as if there isn't enough prims for it

[8:34] WolfPup Lowenhar: i know thee are some places that no mater what when you go there you get hit with so much lagg it is horiable

[8:34] Myla Moody: how would scripted attachments be handled in such a case?

[8:34] Babbage Linden: myla, scripted attachments would use the avatar resource pool

[8:34] Myla Moody: ahh

[8:34] Babbage Linden: which is a constant size

[8:34] Babbage Linden: so that if you attach a bunch of scripts

[8:35] Babbage Linden: you will be able to teleport anywhere

[8:35] Imaze Rhiano: how is script initial memory usage decided? like classic lsl initial memory 16K - mono - initial memory usage 64k?

[8:35] Babbage Linden: without being told that resources are available

[8:35] Babbage Linden: imaze, LSO scripts will still be 16KB always

[8:35] Babbage Linden: if there is 16KB available, an LSL script will rez

[8:35] Babbage Linden: with Mono scripts, we'll probably use the same mechanism initially

[8:36] Babbage Linden: check to see whether there is 64KB availabe

[8:36] Babbage Linden: allow the rez to happen if there is

[8:36] Babbage Linden: but, in future

[8:36] Nock Forager: Currently, do you have in your mind what the memory limit should be?

[8:36] Babbage Linden: we would be able to have Mono scripts request memory

[8:36] Babbage Linden: so they might say I need 2KB

[8:36] Babbage Linden: and be able to rez whenever there is 2KB availabe

[8:36] Babbage Linden: on the other hand, they might say that they want 2MB

[8:37] Babbage Linden: and then be able to use much more memory than scripts can currently use

[8:37] Babbage Linden: without having to break the script up in to tiny parts

[8:37] Sheet Spotter: If the attachment limit is per avatar (i.e., not sim-specific), then high numbers of avatars could impact a sim.

[8:37] Imaze Rhiano: if mono's initial memory is going to be 64k then many script are going to stay in orginal LSL. At least those small one.

[8:38] Babbage Linden: until we allow Mono scripts to request less, yes

[8:39] Nock Forager: perhaps region owner should maintain that's limit maybe? Sheet.

[8:39] Sheet Spotter: Or some combination. The region owner could adjust the limit?

[8:39] WolfPup Lowenhar: but how can we determine whis would be better for a certin type of script?

[8:39] WolfPup Lowenhar: as builders

[8:39] Babbage Linden: we haven't talked about region owner adjustments yet

[8:40] Babbage Linden: i know there are prim bonus settings for prims

[8:40] Imaze Rhiano: wolfpup... initially for simple script LSL would be better - until Mono can request less memory

[8:40] Sheet Spotter: The region owner can adjust the max number of AVs.

[8:40] Sheet Spotter: That might be a crude proxy for limit the number of AV scripts.

[8:41] WolfPup Lowenhar: that is true sheet

[8:41] flopsie McArdle: hi everyone

[8:41] Babbage Linden: open spaces will likely have script limits first

[8:42] WolfPup Lowenhar: and then the regio owner when he parcels the the regein he could set how many AV's on a particular parcel

[8:42] Myla Moody: if the resource limits would initially consider all mono scripts to consume the full 64k memory, my concern is how it would affect multi-use avatar attachments which may contain 30-40 scripts. would these be an issue?

[8:42] Myla Moody: assuming those 30-40 scripts compile and work fine as non-mono, within the old 16k memory limits

[8:43] WolfPup Lowenhar: mayla babbage said that region and av pools are seperate

[8:43] Myla Moody: yes, i heard :)

[8:43] Sheet Spotter: In a heavily populated sim I would be concerned about the impact an AV with 30+ scripts in their attachments has on those around them.

[8:43] Imaze Rhiano: Myla... that would likely mean that only option would be use classic LSL until Mono can decide it's memory usage

[8:43] Obi Woebegone: is there a protocol for questions here?

[8:44] Babbage Linden: obi, yes, ask them :-)

[8:44] Babbage Linden tries to keep up

[8:44] Juls Rosca grins

[8:44] WolfPup Lowenhar: so their might be a limit of how many script would be availabe for say tinting windows and such in the region but the av's would have a different limit

[8:44] Obi Woebegone: I have an issue with physics here... I was hoping to apply forces from several places on a linked object (from child prims) but the results i'm getting are pretty unpredictable

[8:44] Babbage Linden: sheet, an av with 30-40 scripts on them wouldn't have an effect unless everyone had that many scripts and the region itself had many scripts

[8:45] Arawn Spitteler asks, and might be heard: AD Scripting is something I'd think of, but would placing the scripting load where it belongs cost too much on the communications channels.

[8:45] Babbage Linden: only when the combined script memory usage makes the sim swap does it become an issue

[8:45] Babbage Linden: our next job is to work out good settings for the limits

[8:45] Sheet Spotter <-- works and plays on heavily scripted sims with multiple heavily scripted AVs. :-)

[8:45] Obi Woebegone: It seems that only one force and one torque is considered for the entire object - but there is clearly room in the havok engine for forces to be applied locally from all around the object...

[8:46] WolfPup Lowenhar: < work the same place sheet dose :)

[8:46] Nock Forager: People may say "more!" if you choose any limit size :)

[8:46] Obi Woebegone: one could work around this if it was possible to apply a torque to an arbitrary point but I don't see a way to do that... does this make sense?

[8:46] Babbage Linden: nock, yes people will say more

[8:47] Babbage Linden: we're going from "unlimited" to "some limit"

[8:47] Babbage Linden: but we're doing it to avoid the tragedy of the commons

[8:47] Babbage Linden: currently, in some places, everyone over uses the simulators resources

[8:47] Babbage Linden: and so everyone suffers

[8:48] Babbage Linden: but there is also an upside

[8:48] Babbage Linden: we're going from arbitrary 16KB or 64KB limits per script

[8:48] Imaze Rhiano: so it is decided that limit comes? it is not anymore just talk?

[8:48] Babbage Linden: to script sizes only limited by the resources available in the parcel

[8:48] Babbage Linden: or avatar pool

[8:48] Babbage Linden: imaze, no this is still being discussed

[8:48] Babbage Linden: no final decisions have been made

[8:48] Babbage Linden: but it's looking likely

[8:49] Chaley May: if you create limits so people get their fair share of the sims server then you can increase prims :)

[8:49] Myla Moody: purely curiosity question, has anyone toyed with a timeline for beta deployment yet? :)

[8:49] WolfPup Lowenhar: well having the limits is understandable

[8:49] Babbage Linden: chaley, we could move to some super complicated over-engineered solution which allows people to trade of prims vs scripts vs foo

[8:50] Babbage Linden: but i'd really like to come up with something simple that works :-)

[8:50] WolfPup Lowenhar: i used to live on a soiim that has a club and a couple of stores and some time the lag there was awful

[8:50] Babbage Linden: ok, i need to go to another meeting in 10 minutes

[8:50] Babbage Linden: and i need a bio break first

[8:50] Babbage Linden: so, we need to wrap up in a minute

[8:50] Arawn Spitteler: If scripts are alocated by Parcel, not every parcel is going to be used, so there'd be left over resources, and sim owners could allocate multipliers.

[8:50] Babbage Linden: arawn, yes

[8:51] Imaze Rhiano: I hope that you will find to set Mono's memory usage to lower - 64K vs 16K will kill mono until it is fixed.

[8:51] Babbage Linden: we haven't talked much about that yet, but will do

[8:51] Babbage Linden: so, before i go

[8:51] Babbage Linden: i'd like to give you all a set of new carbon goggles

[8:51] Babbage Linden: i fixed a load of bugs last night

[8:51] Babbage Linden: so now it's much more usable

[8:52] WolfPup Lowenhar: kewl

[8:52] Babbage Linden: and it's open source so you have have a look and play with it

[8:52] Babbage Linden: to come up with lots of interesting augmented virtual reality applications in SL

[8:52] Babbage Linden: there you go

[8:53] Babbage Linden: it's set for sale for 0L$

[8:53] Myla Moody: thank you :)

[8:53] Babbage Linden: there's also a Carbon Goggles group you can join if you'd like updates

[8:53] WolfPup Lowenhar: thx

[8:53] Sheet Spotter: Thank you for this time, Babbage. Always interesting to see how the gears are turning within LL. :-)

[8:53] flopsie McArdle: thanks babbage

[8:53] Babbage Linden: let me know if you build anything interesting with it :-)

[8:54] Imaze Rhiano: thanks Babbage

[8:54] Chaley May: thanx

[8:54] Babbage Linden: and I'll be looking at to see if you annotate any objects

[8:54] Chaley May: still not sure what it is i have to read it

[8:54] Chaley May: i thought my avatar would be wearing goggles

[8:54] Babbage Linden: there's more information here:

[8:55] Babbage Linden: ok, now i need to go

[8:55] Babbage Linden: thanks for coming everyone

[8:55] Chaley May: bye

[8:55] Myla Moody: have a great day :)

[8:55] White Platini waves

[8:55] Nock Forager: Thanks for the meeting Babbage

[8:55] flopsie McArdle: bye babbage

[8:55] Juls Rosca waves

[8:56] Babbage Linden: bye!