Re: How cheap/efficient is it to have lots of protocols/instances?

Jason Duell wrote:
> Thinking about the necko protocol layer, I'm realizing I've got a
> choice between two general models:
> 
> 1) Have a single Necko protocol, and one instance per content process,
> over which I multiplex all the channels that are opened.
> 
> 2) Create a "NeckoChannel" sub-protocol of the Necko protocol, and
> create an instance of it per-channel.
> 

Subprotocols are basically free.  They might cause a very small increase 
in code size, but nothing substantial.  Subprotocol actors are also 
pretty cheap: they consist of 2 pointers and an int, and are entered 
into a hash table.

> How expensive, roughly speaking, is IPC traffic?  Do we have data
> structures in place what will keep things efficient with large N
> (well, medium N) numbers of protocol instances? 

Yes, message dispatch is O(1).

I agree with bsmedberg regarding batching.

Cheers,
Chris