[Opensim-users] Slow LSL timers

[Jorge Lima]

My project is simple enough - something like throwing a ball off a
cliff with a horizontal impulse and recording its speed. It's for high
school physics teachers/students.

It seems to me that I can either have a fast timer that simulates the
movement and generates points, or I can have a fast timer that trusts
the physics engine to provide an accurate simulation and records its
output :)

I will look into the Timer.cs file and try out C# scripting tomorrow,
then get back to you. Thanks for the help!

On Sat, Dec 4, 2010 at 6:23 AM, dz <dz at bitzend.net> wrote:
> I'd have to agree with Justin...
>
> Expecting event handling to be optimized is too optimistic, but  there are
> alternatives.  The .Net/Mono libraries already include timer functions that
> support fast and accurate timing.
>
> Relying on an LSL event trigger to happen every 4 frames MAY work in SL but
> it is a design begging to cause lag and  stop itself.  Designs like that are
> also susceptible to event buffer overflows  where your events are "lost",
> leaving you to wonder why your "reliable" script  sometimes just isn't..
> The ONLY LSL events I have seen  requiring sub-second repeats  would be in
> an AO, but timer based AO's are obsoleted in OpenSim by the use of the
> Animation_Changed event.
>
> In the extreme, if you are trying to be  very exact,,  you would want to
> insure the timings were made by processes independent of the region time
> dialations, not the ones that may be responsible for them.
>
>
>
> On Fri, Dec 3, 2010 at 5:35 PM, <opensim-users-request at lists.berlios.de>
> wrote:
>>
>> ---------- Forwarded message ----------
>> From: Jorge Lima <jorge.manuel at gmail.com>
>>
>> Subject: [Opensim-users] Slow LSL timers
>> Ran 100 timer events with a single if(++i > 100) inside. I suppose
>> decrementing and comparing to 0 might be faster, but I also
>> copy-pasted 100 inlined if clauses and the time to run them was
>> negligible.
>>
>> llSetTimerEvent(0.1) -> 59 s -> 490% overhead
>> llSetTimerEvent(0.2) -> 59 s -> 195% overhead
>> llSetTimerEvent(0.5) -> 59 s -> 18% overhead
>> llSetTimerEvent(0.75) -> 81 s -> 8% overhead
>> llSetTimerEvent(1.0) -> 108 s -> 8% overhead
>> llSetTimerEvent(2.0) -> 209 s -> 4.5% overhead
>> llSetTimerEvent(4.0) -> 407 s -> 1.75% overhead
>>
>> I am guessing that the overhead is, therefore, internal to the timer
>> implementation. I haven't tested raw C# timers as comparison but 100ms
>> is an eternity in modern computing, I can ping servers across the
>> Atlantic ocean in less than that!
>>
>> I went through the code but I haven't yet found the part that handles
>> timers. It's not in EventManager.
>> Does anyone know what's going on? The code works fine in SL.
>> Should I be posting this in the dev list? I'd like to see if I can fix it.
>> Any thoughts on how to get fast timers in OpenSim?
>> Faster computer? (I did check and was only getting about 20% CPU usage...)
>> Porting them to a Real-Time operating system? :)
>>
>>
>>
>> ---------- Forwarded message ----------
>> From: Justin Clark-Casey <jjustincc at googlemail.com>
>> To: opensim-users at lists.berlios.de
>> Date: Sat, 04 Dec 2010 01:35:32 +0000
>> Subject: Re: [Opensim-users] Slow LSL timers
>
>
>>
>> I'm not familiar with the this area of the code but I had a quick look
>> since I was curious (the meat is in
>> OpenSim/Region/ScriptEngine/Shared/Api/Plugins/Timer.cs).  The code isn't
>> using C# timers so I'm not totally surprised at the behaviour that you're
>> seeing.
>>
>> I suspect addressing this would require a considerably different
>> implementation.
>>
>
> _______________________________________________
> Opensim-users mailing list
> Opensim-users at lists.berlios.de
> https://lists.berlios.de/mailman/listinfo/opensim-users
>
>