On Friday 02 December 2011 10:23:49 you wrote:
> My program use co-threads, because creating and reinitialize thread is
> expensive, it first create threads and reuse them. The main thread
> will send each co-thread a event (through condition variable)
> simultaneously to do task in parallel way. Each co-thread has variety
> work-time, let say it can be (in miliseconds) 200ms, 130ms, 317ms,
> 90ms etc to get result to be consumed by main thread.
>
> Here I did to wake-up all threads in the main thread:
>
> .....
> for (i = 0; i < nthread; i++)
> pthread_cond_broadcast(&cond);
> wait_all_worker(); /* wait for all worker threads to finish */
> get_all_worker_result(); /* get result from all worker thread */
> ...
>
>
> And worker-thread routines:
>
> ...
> for (;;) {
> pthread_mutex_lock();
> pthread_cond_wait();
> pthread_mutex_unlock();
>
> do_work();
> fill_result();
> }
> ....
>
> My dilema is:
>
> 1. What the proper way to the main thread to wait for all co-threads
> until finished?
I would use a semaphore which should be locked by the treads once the
condition variable is set en unlocked when the result is available for the
main thread.
> 2. After calling pthread_cond_signal() or pthread_cond_broadcast()
> followed by sleep()/nanosleep(),
> the condition variable looks like not signaled, (the co-thread
> routine doesn't run). What make this?
I don't understand, please provide a working example
--
Bogdan
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