[Qt-interest] efficient Wait for Thread finished?

[Arnold Krille]

On Tuesday 20 January 2009 12:04:32 Bradley T. Hughes wrote:
> Matthias Pospiech wrote:
> > How should it look like?
> Why aren't you using QThread::wait()?

Anything with wait( X ) is a not so optimal solution as the quantization you 
choose for the wait will have an influence on the performance. Either you are 
checking to often, thus stealing valuable calculation time or you are checking 
not often enough and thus introduce dead-time.

As the various mutexes and semaphores in Qt have platform-specific 
implementations, these allow for the waiting thread to really sleep and get 
woken up by the kernel/os only when the condition is met (or a timeout 
occured), not at regular intervals.

Another solution would be to use a ringbuffer (or fifo) for the communications. 
This would have several advantages: The buffer would only need a lock when it 
gets full and the reading thread could read (and save) multiple datasets at 
once which could make better use of disk-bandwidth.

Have fun,

Arnold
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