[sldev] Script/Parcel/Memory Limits

[Aleric Inglewood]

On Wed, Dec 16, 2009 at 2:03 AM, Stickman <stickman at gmail.com> wrote:
> The comfort or early warning I expect is that we're going to get
> better tools to see behind the scenes on scripts before the limits
> actually show up. My fear is that it's going to be right when midterms
> crop up and have a two week window to rewrite every script I've ever
> written.
>
> Can any Lindens on this project provide any information, or point us
> to a magical page on the wiki that explains this? Or, at the very
> least, give us a rough timetable so we know about what time is
> appropriate to begin our panicked search for information?

To save him from typing this again, here is some info about this
topic from IRC. I editted it (removed other conversation):

[23:53] <tehKellz> Aleric: in general script run time isn't an issue.
Scripts do run fast, and we dedicate a fairly fixed amount of time
each simulator frame to running scripts.

[23:54] <Aleric> tehKellz: If you are going to set limits on scripts,
you should not do so in any way that normal scripters are affected
imho. Only those that really try to abuse it.  You cannot set limits
per-script in order to control the server load; the only way to do
that is using load balancing (NO limits for a script if there is
enough resources)
[23:55] <tehKellz> Sure, I can cover some points here:

[23:55] <tehKellz> *) Correct.  When we start enforcing limits most
won't notice, only those extreme cases.

[23:56] <tehKellz> (everyone just always assumes they will be effected)
[23:56] <tehKellz> *) We won't be limiting CPU (for now at least) just memory

[23:56] <tehKellz> *) The limits aren't "per script" but "per region"
and "per avatar".  A region will get probably ~300MB for scripts.
give or take.

[23:57] <tehKellz> *) The problem being solved isn't performance
because of script run time.  It is because when memory bloats too much
it pushes sims into swap which kills the performance not only of that
region but every other region on the host.
[...]
[00:00] <tehKellz> In all cases, even if the memory limits we set are
1gig of mem for scripts per region, the truth is that we *do* have a
tragedy of the commons problem and we need the limits.