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List of biggest contributors to lag and sim load?

Fushichou Mfume
Registered User
Join date: 30 Jul 2005
Posts: 182
09-16-2005 07:58
I've become more aware of things that cause bad client framerate and generally degrade sim framerate. Experimenting with things on my own land has surprised me in some regards. I've known that any script that uses active sensors tends to be bad. I was more surprised to learn that something like a fog machine can make a noticeable hit.

Can we get a list of things to avoid in a build if you're looking for the minimal impact on sim framerate and local client framerate for visiting AVs? Yes, I know that AVs themselves often wear things that kill framerate (hoochie hair, lots of bling, and other things). It would be good to list those as well, I suppose.

So, if you have any input, please try to list the most common "big offenders" for both AVs and builds. Thanks!
Pendari Lorentz
Senior Member
Join date: 5 Sep 2003
Posts: 4,372
09-16-2005 08:10
Well, one resource I always like to compare my items to is this list of scripting tips in the scripting forums. Since scripts can be a major part of what causes lag. That thread is here:

Good Scripting Standards - let's formalize this
/54/5b/46104/1.html

I know there are other lag causing things, but for scripts, this list is a start at least! :D
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Richie Waves
Predictable
Join date: 29 Jun 2005
Posts: 1,424
09-16-2005 08:11
Willows Inventory :p
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Kris Ritter
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Join date: 31 Oct 2003
Posts: 6,627
09-16-2005 08:12
ME!
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09-16-2005 08:13
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Aimee Weber
The one on the right
Join date: 30 Jan 2004
Posts: 4,286
09-16-2005 08:13
From: Fushichou Mfume
I've become more aware of things that cause bad client framerate and generally degrade sim framerate. Experimenting with things on my own land has surprised me in some regards. I've known that any script that uses active sensors tends to be bad. I was more surprised to learn that something like a fog machine can make a noticeable hit.

Can we get a list of things to avoid in a build if you're looking for the minimal impact on sim framerate and local client framerate for visiting AVs? Yes, I know that AVs themselves often wear things that kill framerate (hoochie hair, lots of bling, and other things). It would be good to list those as well, I suppose.

So, if you have any input, please try to list the most common "big offenders" for both AVs and builds. Thanks!


I would love to see this quantified. A great building tool would be some kind of chart that lists all the prims types, texture sizes, and scripting features along with some kind of lag index for server and client. I fear it may not be possible, but if it were it would be a really valuable tool for making judgement calls.

Example: Should I use 15 prims with the same simple 128x128 pixel texture, or should I build the same thing using one large prim with a detailed 512x512 sized texture? (I don't really need the answer to this but it's the KIND of question that often comes up while building)
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Margaret Mfume
I.C.
Join date: 30 Dec 2004
Posts: 2,492
09-16-2005 08:30
From: Fushichou Mfume
Yes, I know that AVs themselves often wear things that kill framerate (hoochie hair, lots of bling, and other things).


Hootchie hair and bling are often cited but what about those other things? How do they rank on the lag inducing scale? I'm wondering if I would be less of a burden as a visitor in your sim if I wasn't wearing my ROAM? I'd gladly relinquish it if LL would activate P2P teleporting without any regret over the year's subscription which I paid for the service.

How about my PersonalSecurity device? Is that better or worse than the hootch? Giving up that would require a system which more effectively deals with griefers. There's no quick fix for that.

I really hate to bring up my next item, as it is my favorite. What about my Skoopf Skates? How badly am I imposing upon other people's performance by indulging myself with that whimsy?

I want to have an environmentally friendly avatar so please inform. Must I just say no to my halo?
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Chosen Few
Alpha Channel Slave
Join date: 16 Jan 2004
Posts: 7,496
09-16-2005 08:56
Well, if you want to talk client FPS, then one of the biggest killers is textures. Think about the average mall in SL. There are literally gigabytes worth of textures in it, in some cases even terrabytes, but the average video card can only process in the megabytes. Most builders in SL are way too thoughtless to consider the importance of keeping textures small and repeating the same ones as much as possible.
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Pendari Lorentz
Senior Member
Join date: 5 Sep 2003
Posts: 4,372
09-16-2005 09:00
From: Chosen Few
Well, if you want to talk client FPS, then one of the biggest killers is textures. Think about the average mall in SL. There are literally gigabytes worth of textures in it, in some cases even terrabytes, but the average video card can only process in the megabytes. Most builders in SL are way too thoughtless to consider the importance of keeping textures small and repeating the same ones as much as possible.



Yes! I know this is a big thing to consider too!

Can anyone list the sizes that I've heard are good to go by (from smallest to highest). It is in some muliple of something. I tend to end up just using 512 x 512 so often. I forget the other ones. :o
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Aimee Weber
The one on the right
Join date: 30 Jan 2004
Posts: 4,286
09-16-2005 09:05
From: Chosen Few
Well, if you want to talk client FPS, then one of the biggest killers is textures. Think about the average mall in SL. There are literally gigabytes worth of textures in it, in some cases even terrabytes, but the average video card can only process in the megabytes. Most builders in SL are way too thoughtless to consider the importance of keeping textures small and repeating the same ones as much as possible.


I totally agree (this is why we enforce texture size limitations in Midnight City and I noticed they do the same in Amsterdam).

The question is, how many prims = a large texture when it comes to lag? Would it be better for me to make a building using no textures but dozens of prims to form doors and windows...or use a single prim with a large texture that depicts those doors and windows?

Quantifying the lag generated by different facets of SL seems like it would be a good project for some of the brilliant minds floating around here :D I know I would use the results on a daily basis too!
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Ellie Edo
Registered User
Join date: 13 Mar 2005
Posts: 1,425
09-16-2005 09:06
From: Aimee Weber
Example: Should I use 15 prims with the same simple 128x128 pixel texture, or should I build the same thing using one large prim with a detailed 512x512 sized texture? (I don't really need the answer to this but it's the KIND of question that often comes up while building)
In this case, Aimee, can't you have the best of both worlds, by using the one big prim, and setting "repeats" to replicate the 128x128 across it ?
Aimee Weber
The one on the right
Join date: 30 Jan 2004
Posts: 4,286
09-16-2005 09:11
From: Ellie Edo
In this case, Aimee, can't you have the best of both worlds, by using the one big prim, and setting "repeats" to replicate the 128x128 across it ?


Often yes! But sometimes no. The details being represented by the 128x128 texture could be scattered.

The other example I gave of an office building is one I delt when I was making the skyscapers in Midnight City. I wanted some of the windows to be illuminated, and some not (like real buildings at night) but they only looked good in a random pattern. If repeats were used it looked VERY unnatural.
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FlipperPA Peregrine
Magically Delicious!
Join date: 14 Nov 2003
Posts: 3,703
09-16-2005 09:12
Wow, this conversation again!

:-)

One idea for textures, to give incentive to keep size reasonable, AND create a new L$ sink... pay by the pixel!

256x256 (65536 pixels) texture or smaller = L$10 to upload
512x256 or 1024x128 (131072 pixels) textures = L$20 to upload
512x512 (262144) textures = L$40 to upload
1024x1024 (1048576 pixels) = L$160 to upload

This would make people more responsible about using reasonable texture sizes instead of always going for the big ones. :-) I've seen people with 40 object boxes in a mall setting with all 1024x1024 textures - not because they're evil, just because they don't know any better! This would force the learning curve.

I won't go into my opera about sensors, timers and listeners - its well documented - except to say that YES, arrogant coding that uses open listeners on channel 0 (which also causes CHAT SPAM), and other channels simultaneously still gets under my skin... as do timers set to run 10 times a second unnecessarily and llSensorRepeat set to anything more than twice a minute.

Regards,

-Flip
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Chosen Few
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Join date: 16 Jan 2004
Posts: 7,496
09-16-2005 09:17
From: Pendari Lorentz
Yes! I know this is a big thing to consider too!

Can anyone list the sizes that I've heard are good to go by (from smallest to highest). It is in some muliple of something. I tend to end up just using 512 x 512 so often. I forget the other ones. :o

It's all powers of two. 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024...

For most applications, 256x256 is a nice happy medium, allowing enough room for detail without a huge file size. The important thing to consider when choosing a texture size is how much of the screen is the image intended to occupy under normal circumstances. If it's a tire tread on a car, then chances are it's only going to require just a few pixels since people are likely to look at the car as a whole, and never focus just on the tire tred. If it's the ceiling of the Sistine Chapel, then chances are it's going to be viewed full screen, so it should be fairly large, maybe 1024x1024.

The rule of thumb I usually sugest is that 75% of your textures should be 256x256 or smaller, 20% of them should be 512x512, and 5% should be 1024x1024.

One of the most commonly oversized images are signs. It's crazy how many people put 1024x1024 sized textures on a 2-foot sign in a store. The guideline for signs really should be to make the image just big enough so that the text is clearly legible when the image is viewed at 100% magnification in Photoshop. If it's a one-word sign, then 64x128 is usually plenty big enough. If it's more informational, then do what you have to do to make it legible, but no more.
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Aimee Weber
The one on the right
Join date: 30 Jan 2004
Posts: 4,286
09-16-2005 09:21
From: FlipperPA Peregrine
Wow, this conversation again!

:-)

One idea for textures, to give incentive to keep size reasonable, AND create a new L$ sink... pay by the pixel!

256x256 (65536 pixels) texture or smaller = L$10 to upload
512x256 or 1024x128 (131072 pixels) textures = L$20 to upload
512x512 (262144) textures = L$40 to upload
1024x1024 (1048576 pixels) = L$160 to upload


I'm fine with this, particularly since the fees aren't scaled more than the pixels (If 1024x1024 were to cost more than 16 times the price of a 256x256 it would discourage those of us that try to combine textures into a texture sheets, another lag saving technique)
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FlipperPA Peregrine
Magically Delicious!
Join date: 14 Nov 2003
Posts: 3,703
09-16-2005 09:22
From: Pendari Lorentz
Yes! I know this is a big thing to consider too!

Can anyone list the sizes that I've heard are good to go by (from smallest to highest). It is in some muliple of something. I tend to end up just using 512 x 512 so often. I forget the other ones. :o


Pendari, I'll take a stab at explaining how all this texture size stuff works. Textures width and heigh are coverted to the nearest power of two. So, textures can be any combination in X and Y of (eliminating super small ones):

32, 64, 128, 256, 512, 1024

128x1024 is valid. 32x32 is valid. 1024x64 is valid... etc. :-)

A 512x512 will (typically) load about 4 times as fast as the same graphic at 1024x1024.
A 256x256 will (typically) load about 16 times as fast as the same graphic at 1024x1024.

Also, due to compression and artifacting - and the sharpening filter SL uses - graphics will often look *better* at lower resolutions than the higher ones.

Now, consider the problem I posted above, of the friend I had in our mall who just didn't know any better.

She had, on a single 10 meter by 10 meter wall, forty 1 meter by 1 meter boxes, each with a different 1024x1024 texture displaying the item that was being sold.

Since a 1024x1024 texture is 1048576 pixels, and a 256x256 texture is 65536:

The sim was forced to send (1048576 times 40) = 41943040 pixels worth of data, instead of 2621440 pixels worth of data to every client.

In this example, we reduced the pixels downloaded per avatar viewing from:
41943040
to:
2621440

You're looking at orders of magnitude now... now imagine having 20 people in the mall area. It goes up MUCH higher, again.

This is why keeping your texture sizes small is so important... if you EVER want stuff to rez for people who don't have it cache'd on their hard drive. :-)

Make sense? :-)

-Flip
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Pendari Lorentz
Senior Member
Join date: 5 Sep 2003
Posts: 4,372
09-16-2005 09:55
Wow!! Thank you Chosen and Flip! That all makes perfect sense. I'm going to bookmark this thread!! :D
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Omaire Abattoir
O-Magine
Join date: 26 Jun 2004
Posts: 86
09-16-2005 12:46
Flipper,

Now THAT, was a great explanation.

Let me, hearby, apologize to those who I've lagged out, I've always tried to keep textures small but I know I have some 1024x1024's wandering around out there somewhere.

This is a very good thread and should be saved somewhere.

Thanks again!

Omaire
Julian Fate
80's Pop Star
Join date: 19 Oct 2003
Posts: 1,020
09-16-2005 13:16
From: Aimee Weber
(If 1024x1024 were to cost more than 16 times the price of a 256x256 it would discourage those of us that try to combine textures into a texture sheets, another lag saving technique)

Does it really reduce lag? Is that conventional wisdom or documented somewhere?

I support a graduated scale of upload fees, but only if the fees are retroactive. :) No, really, that's a good idea but something more like:
CODE
0x0 - 256x256	L$10
512x512 L$50
1024x1024 L$Eleventy-kajillion
Aimee Weber
The one on the right
Join date: 30 Jan 2004
Posts: 4,286
09-16-2005 13:26
From: Julian Fate
Does it really reduce lag? Is that conventional wisdom or documented somewhere?

I support a graduated scale of upload fees, but only if the fees are retroactive. :) No, really, that's a good idea but something more like:
CODE
0x0 - 256x256	L$10
512x512 L$50
1024x1024 L$Eleventy-kajillion


Well I have had discussions with some of the engineers about this and the answer to your question is... "sometimes" LOL.

Making texture sheets (that is, putting 16 different 256x256 textures onto one 1024x1024 texture) reduces some of the overheard that would have been duplicated 16 times if 16 different files were used. So overall the amount to data that needs to be downloaded will be less.

However Second Life prioritizes texture loading based on what you are looking at, and spares you that load time for things far away. So if you make a texture sheet for 16 textures that will appear on a single vehicle or building, you should enjoy the benefits of reduced overhead.

HOWEVER, if you make a texture sheet for something like...all the road signs in your sim, then it would mean that when you look at a single 256x256 stop sign, SL has to send you a 1024x1024 texture that features all kinds of stuff you aren't looking at! Obviously a bad decision.
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Moxie Grumby
the errant Miss Cupcake
Join date: 29 Apr 2005
Posts: 48
09-16-2005 13:54
I'm one of the people who doesn't know better but would like to.

I've been making building textures lately and setting them at 512x512. As soon as I get home I'll change them to be 256x256, I promise.

Another question though - I have a penchant for building objects out of light, partly because I love the way it looks and partly because in the deep dark of SL night, I can't see a damned thing. However, does this add to lag? If so I'll have to find another solution.

And thanks for this thread - these are issues that would just never occur to folks- especially new-ish ones like me.
Fushichou Mfume
Registered User
Join date: 30 Jul 2005
Posts: 182
09-16-2005 14:01
Okay great conversation so far. I get that texture loading is an *initial* drain on every AV coming into draw distance of a given texture. If you have AVs coming and going in that location, they are all taking sim resources up, because the sim keeps having to upload lots of texture info to people who don't have it cached already.

That's good to know and design around, but....

... it's a one-time load on the server (per AV anyway). Once you have a relatively stable population in a given space, like a dance floor in a club, the texture issue goes away after every AV has had them loaded up.

What I'm also curious about, perhap more curious, are the typical script offenders, and perhaps the more common items used by many AVs, that contribute to *ongoing* performance drops. For example, tons of AVs have animation overrides, dance bracelets, hug/kiss/bite devices, poof balls, ROAM units, flight packs, bling jewelry, etc. Are any of these *very* common accessories especially big offenders? What makes them big offenders?

Why is it I can go to one club and its essentially lag-free (relatively speaking) and I can go to another club and I'm lucky to get 4FPS on my client? Why does one new AV show up at a club and suddenly a scrubbie (or your status window) show the sim suddenly divebombing, as well as your own client framerate plummeting?

And a related question: Why can my client be humming along at 15 to 23 FPS and suddenly my partner's machine (in the room next to me) suddendly divebombs to 4 FPS and nothing will fix it for her but to relog? Why can most people at a club location experience decent framerate, while another person complains of having horrible framerate? Why is the sky blue? Why did we elect an idiot as our president for a second term even after it was clear to everyone buy then that he was an idiot? (Sorry, couldn't resist--please ignore that if you're in the dubya camp.)
Julian Fate
80's Pop Star
Join date: 19 Oct 2003
Posts: 1,020
09-16-2005 14:04
From: Moxie Grumby
Another question though - I have a penchant for building objects out of light, partly because I love the way it looks and partly because in the deep dark of SL night, I can't see a damned thing. However, does this add to lag?

Oh yes, light objects can be a significant factor in client lag. There are two possible solutions, 1) In 1.7 (coming soon!) you can set textures Fullbright, meaning they appear lit but don't cast light which should help performance, and 2) There is a slider in the SL preferences for nighttime brightness that can make a big difference. Be aware that it is labelled incorrectly and is darkest at what should be the lightest setting.
Nala Galatea
Pink Dragon Kung-Fu
Join date: 12 Nov 2003
Posts: 335
09-16-2005 14:23
From: FlipperPA Peregrine
One idea for textures, to give incentive to keep size reasonable, AND create a new L$ sink... pay by the pixel!

256x256 (65536 pixels) texture or smaller = L$10 to upload
512x256 or 1024x128 (131072 pixels) textures = L$20 to upload
512x512 (262144) textures = L$40 to upload
1024x1024 (1048576 pixels) = L$160 to upload

This would make people more responsible about using reasonable texture sizes instead of always going for the big ones. :-) I've seen people with 40 object boxes in a mall setting with all 1024x1024 textures - not because they're evil, just because they don't know any better! This would force the learning curve.


I find your ideas inspiring and/or intriguing and wish to subscribe to your newsletter. :D
Shadow Weaver
Ancient
Join date: 13 Jan 2003
Posts: 2,808
09-16-2005 14:40
Hey I know how about you RICH Famous people pay more for upload Charges based on your chart and leave us little business people alone.

Or Better Yet all y'all advocating this pay OUR upload charges bet that will change your minds quickly....

Shadow
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