[sldev] Cache speed experiment & results...

[Carsten Juttner]

Sean Lynch wrote:
>
> I thought we already had a separate texture decoding thread; isn't 
> that what "enable multiple threads" does in the advanced menu?

I looked at that code a while ago, from what I saw threads are always 
enabled (but note that not every "thread" that is derived from one of 
the thread classes is actually run threaded. The place to look at here 
is initThreads() in llappviewer.cpp.

So if I see this correctly, texture decoding and texture caching thread 
are currently run threaded, only the texture fetching is not.

As for the advanced switch "Run Multiple Threads": if it is enabled, the 
texture decoding and caching threads are run in parallel with rendering, 
else they are put to sleep right before (but they are not frozen so I 
guess depending on the workload it's possible that one of them extends 
into the begin of rendering which is probably the cause for VWR-4067 
since it occured in a debug build where things naturally run a bit slower).

Also if MEM_TRACK is defined, threading is disabled (all "threads" run 
in the main thread in this case).


Carsten