Re: [Boost-users] [Threads] How to keep number of running thread constant, performing different operations

On Fri, Jun 17, 2011 at 10:12:47AM +0200, Ovanes Markarian wrote:

On Fri, Jun 17, 2011 at 9:05 AM, Alessandro Candini wrote:

...

I have different threads which have to work on completely different input and output data (non critical sections): an atomic operation per thread, each one with different time execution but everyone with an intense use of the CPU. Let's say I have 10 operations to perform (10 threads): I would like to run concurrently only 2 threads because of resource consumption.

My problem is that when a threads ends its execution, I would like to suddenly start another thread performing operation 3, in order to have constantly 2 threads working, and so on until the end of operations.

How can I achieve this? I thought to insert my threads into a vector...but I have no idea on how start and join them in order to obtain what described above.

Can anyone post me a little example?

Thanks in advance.

I think you should use a thread pool. You can extend your thread pool with more threads, without impacting other application parts. Take a look at this thread pool implementation: http://threadpool.sourceforge.net/tutorial/intro.html

Or you could stick to the things that are in Boost, like Boost.Asio. Create an asio::io_service; create an asio::io_service::work to keep the workers alive; start N threads, each running asio::io_service::run(); enqueue work by invoking asio::io_service::post() with your tasks. When you're done, destroy the 'work' object and the run() calls will terminate when they're done. For managing the N threads, you can use a thread_group. -- Lars Viklund | zao@acc.umu.se