Other parts of OpenSimulator are relying on SP.Velocity == 0 for vehicles.
So add and use SP.GetWorldVelocity() instead when we need vehicle velocity, along the same lines as existing SP.GetWorldRotation()
As per http://wiki.secondlife.com/wiki/LlSetStatus
Setting STATUS_BLOCK_GRAB_OBJECT prevents or allows move of a physical linkset by grab on any prim.
Setting STATUS_BLOCK_GRAB prevents or allows move of a physical linkset by grab on a particular prim.
Previously, setting STATUS_BLOCK_GRAB would prevent drag via all prims of the linkset.
This was previously effectively being done by XmlDocument in the multiple passes through the XML.
This change tells XmlReader to ignore whitespace. This also means changing arguments to use XmlReader instead of XmlTextReader (a descendent of XmlReader) directly.
XmlReader.Create() has been the recommend way to create XML readers since .NET 2.0 as per MS SDK and is the only way to specific ignore whitespace settings.
Reading large XML documents (e.g. complex attachments) is CPU expensive - this must be done as few times as possible (preferably just once).
Reading these documents into XmlDocument is also more resource intensive than using XmlTextReader, as per Microsoft's own publication "Improve .NET Application Performance and Scalability"
Optimization of other cases will follow if this change is successful.
This is to see if an inaccuracy in sleep times under load is responsible for increase in frame times even when there is spare time still available.
Can currently only be activated by setting "debug scene set update-on-timer true".
Can be switched between timer and thread with sleep updates whilst the scene is running.
However, many locks remain since they may effectively be providing transactionality in some operations (e.g. prim updates across multiple tables).
These are candidates for being replaced with proper database transactions, since this would not block unrelated operations (e.g. land save and object save)
or unrelated operations on the same tables (e.g. storage of one linkset whilst another is being removed).
In practice, any performance deg due to contention is probably rare and short lived as the major prim operations are performed in memory and only persisted some time afterwards.
These locks are not necessary since the connection is taken from the underlying mysql pool and not shared.
Such locking is already not done by some other parts of OpenSim.Data.MySQL.
Pointed out by arribasim-dev
Disabled by default. Currently can only be enabled with console "debug lludp oqre start" command, though this can be started and stopped whilst simulator is running.
When a connection requires packet queue refill processing (used to populate queues with entity updates, entity prop updates and image queue updates), this is done via Threadpool requests.
However, with a very high number of connections (e.g. 100 root + 300 child) a very large number of simultaneous requests may be causing performance issues.
This commit adds an experimental engine for processing these requests from a queue with a persistent thread instead.
Unlike inbound processing, there are no network requests in this processing that might hold the thread up for a long time.
Early implementation - currently only one thread which may (or may not) get overloaded with requests. Added for testing purposes.
Also closes behaviours on disconnect instead of interrupt, though this makes no practical difference.
If existing behaviour is None, other added behavious will not take affect until None is removed (as this is an infinite wait until interrupted).
If n > 1 for RootTerseUpdatePeriod only every n terse update is actually sent to observers on same region, unless velocity is effectively zero (to stop av drift).
If n > 1 for ChildTerseUpdatePeriod only every n terse update is sent to observers in other regions, unless velocity is effectively zero.
Defaults are same as before (all packets are sent).
Tradeoff is reduction of UDP traffic vs fidelity of observed av mvmt.
Increasing n > 1 leads to jerky observed mvmt immediateley for root, though not on child, where experimentally have gone to n = 4 before jerkiness is noticeable.
Rapid polls are more expensive than triggered events (several polls vs one trigger) and may be problematic on heavily loaded simulators where many threads are vying for processor time.
A triggered event is also slightly quicker as there is no maximum 200ms wait between polls.
This is already going to be correctly set by WaitForUpdateAgent() earlier on in that method, which is always called where a callback to the originating region is required.
This kind of polling is very expensive with many bots/polling threads and appears to be the primary cause of bot falloff from the client end at higher loads.
Where inbound packet threads can't run in time due to contention and simulator disconnect timeout occurs.
This adds the "show stats", "stats record", etc. commands and information on available Threadpool threads, etc.
It also adds the Watchdog which logs warnings if time between executions is unexpectedly large.
This is to avoid issues where many bots connect to a single end point with multiple regions, where each region requires a long-lived poll connection for each bot.
Justin Clark-Casey (justincc)