multithreading - Executing multiple PHP scripts in parallel, and being notified when finished

Question

So, that's what I'm trying to do - pretty self-explanatory actually :

• Initiate X 'simultaneous' processes (each bound to a different php script)
• Be able to say when all of them are finished

I've had a look at various different approaches, and I'm probably going to use exec and background processes. (Something along these lines).

The thing - which I really can't get my head around - is :

I can't figure out which is the most efficient way to check whether ALL of the processes are finished (being able to keep an eye on the general progress - e.g. X out of Y finished, is also a must).

What is important is time-efficiency, and - obviously - not causing any unnecessary server overload (so, I suppose any 'frozen' while loop checking for live pids, even if at intervals, is out of the question, right?)

ANY suggestions are very much welcome!

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P.S.: I've initially set this whole thing up with asynchronous Ajax requests starting from the client-side, but I'm currently considering a migration to a non-javascript fully-server-side environment. The issue with parallel-processing though remains...

Answer 1

You should investigate the pcntl_fork and related functions. This allows one master process to form a number of child processes and be notified of child exit status.

http://php.net/manual/en/function.pcntl-fork.php