[Python-ideas] channel (synchronous queue)

[Sturla Molden]

Den 19.02.2012 20:04, skrev Guido van Rossum:
> I think Matt Joiner's original post hinted at some. Matt, could you 
> elaborate? We may be only an inch away from getting this into the 
> stdlib... 

One thing I could think of, is "atomic messaging" with multiple 
producers or consumers talking on the same channel. E.g. while process A 
sends a message to process B, process C cannot write and process D 
cannot read. So you always get a 1 to 1 conversation.

But I am not sure why (or if) Go has this mechanism.

On the other hand, if we put in N**2 pipes (or channels), we could 
achieve the same atomicity of transaction by having an index for sender 
and receiver of a message. This is what MPI does in the functions 
MPI_Send and MPI_Recv. But then I will be scolded for using to many 
semaphores on FreeBSD again :-(

But there are some other useful mechanisms from MPI (and ØMQ) to 
consider as well. For example message broadcasting, message scatter and 
gather, and reductions. The latter is a reduce operation (e.g. add or 
multiply) on messages coming in from multiple processes. OpenMP also has 
reductions in the API. So there is a lot to be considered on the area of 
concurrency if we want to put in more classes in threading and 
multiprocessing.

But now I'll stop before someone tells me to take this to the 
concurrency list :-)


Sturla