Asynchronicity in D

[Brad Roberts]

On Fri, 1 Apr 2011, Sean Kelly wrote:

> On Apr 1, 2011, at 12:59 PM, Jonas Drewsen wrote:
> 
> > On 01/04/11 17.21, Sean Kelly wrote:
> >> 
> >> On Apr 1, 2011, at 7:49 AM, Jonas Drewsen wrote:
> >>> 
> >>> There doesn't have to be a thread for each socket. Actually many servers have very few threads with many sockets each. 32000 sockets is not unimaginable for certain server loads e.g. websockets or game servers. But I know it is not that common.
> >> 
> >> Hopefully not at all common.  With that level of concurrency the process will spend more time context switching than executing code.
> > 
> > For services where clients spend most time inactive this works. An example could be a server for messenger like clients. Most of the time the clients are just connected waiting for messages. As long as nothing is transmitted no context switching is done.
> 
> Fair enough.  Though I'd still say it's a terrible use of resources, given available asynchronous socket APIs.  And as an aside, I think 32K sockets per process is not at all surprising.  I've seen apps that use orders of magnitude more than that, though breaking the 64K barrier does get a bit weird.

I've got an app that regularly runs with hundreds of thousands of 
connections (though most of them are mostly idle).  I haven't seen it 
break 1M yet, but the only thing stopping it is file descriptor limits and 
memory.  It runs a very standard 1 thread per cpu model.  Unfortunatly, 
not yet in D.

Later,
Brad