[Live-devel] Problems with RTSPClient, CSeq variable and SANYO network cameras ...

[Ross Finlayson]

>I personally find your disdain for threads antiquated and naive

This shows a lack of understanding.  It's like saying that the 
designers of a bullet train have a "disdain" for air transportation, 
or conversely that the designers of an aircraft have a "disdain" for 
rail transport.  On the contrary.  We are talking about two 
completely different computation models, each with their pros and 
cons.

I have been programming with threads since the mid 1980s - but for 
the LIVE555 libraries, I chose a single-threaded event-driven model 
instead.  This works well for the type of applications that these 
libraries are typically used for, especially given that lots of 
inexperienced programmers (far more than I had originally 
anticipated, actually) are using the software.

If anyone is interested in this topic, I encourage them to view 
Professor John Ousterhout's slide presentation: 
http://www.softpanorama.org/People/Ousterhout/Threads/tsld001.htm 
(Personally, I wouldn't state the conclusion quite as strongly as he 
does, but - as a very experienced threads programmer myself - I agree 
with the general argument.)


>BTW Have you ever encountered anyone that has ever successfully 
>implemented a TaskScheduler that was multi-threaded?

In principle, it would be possible to replace the "event loop" with 
an "event pool" that contains events (tasks) that could be claimed 
and acted on concurrently by multiple threads (i.e., with each thread 
claiming and acting on a single event (task) at a time).  This would 
not, however, eliminate potential problems with concurrent access to 
shared data structures - so programmers (especially inexperienced 
programmers) would still likely run into problems there.  (Plus, 
problems might arise from having events being handled in an 
unexpected and non-deterministic order.)  So, the "multi-threaded 
event pool" would be a different computation model again from the 
existing "single-threaded event loop" - and one that it's unlikely 
that I would support, absent a complete redesign of the whole 
software.
-- 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/