Just how much slower are events? I have written a streaming XML parser (that can handle open-ended and incomplete documents) and by tearing out the events and using an interface instead I got a significant speed boost.
Does any one else have any war stories?
(Let's not open the GC can of worms here, we all know it's broken :))
Events are really just delegates. From what I recall, they were made much faster in the 2.0 CLR. I'm surprised that replacing events with an interface made your code significantly faster - in my experience they're pretty fast, and if you're dealing with XML, I wouldn't have expected the event calls to be the bottlenecks.
Did your code constantly subscribe to and unsubscribe from events? Do you have any indication of the number of event calls that were made when parsing a particular document?
If there's no reflection involved in the calls then I assume the overhead is pretty negligible. Assumption could be wrong of course . Do you have a micro benchmark to demonstrate this?
Events are definately slower than a straight function call, i can't tell you exactly how much slower, but significantly. You could also pass delegates around for "middle" ground. The .NET event system uses delegates, but calling a method directly through the delegate vs the whole event system is still faster.
Delegates have a slight overhead compared to virtual method calls because they're lists of methods and can therefore theoretically invoke multiple handlers.