> Guys,
> I know my question is long, but it is actually very simple. It can be
> summarized as: "Have you used shared_mutex and shared_locks and have you
> seen an improvement against regular locks?"
>
> Thanks, any comments appreciated
>
> Alessandro
>
> On Aug 25, 2009, at 7:27 AM, Alessandro Bellina <
abellina@gmail.com> wrote:
> > Hello
> > I am testing the boost mutex/lock classes in order to implement a
> > multiple reader single writer model.
> >
> > Because of this I thought that the shared mutex with lock_shared and
> > lock_unique would be perfect. I'm finding that the performance is no
> > better than with a simple mutex.
> >
> > My writer is adding a bunch of elements, locking the shared container
> > exclusivelly until it is done. The readers looks at all elements of the
> > container, locking on a per element basis.
> >
> > Any ideas as to why the shared mutex would be slower in this case than
> > the simple mutex?
> >
> > This is the code for my producer thread and my consumers (as a side note,
> > employee_set is a multi index):
> >
> >
> > typedef boost::shared_mutex mutex_type;
> > typedef boost::shared_lock<mutex_type> read_lock_type;
> > typedef boost::unique_lock<mutex_type> write_lock_type;
> >
> > static mutex_type rw_mutex;
> > struct ConsumerThread{
> > ConsumerThread (employee_set* e):es(e){}
> > void operator()(){
> > for (int i=0; i<es->size(); i++){
> > read_lock_type l(rw_mutex);
> > es->get<1>();
> > }
> > }
> > employee_set* es;
> > };
> >
> > struct ProducerThread{
> > ProducerThread(int n, employee_set* e):N(n),es(e){}
> > void operator()(){
> > write_lock_type l(rw_mutex);
> > for (int i=0; i<N; i++){
> > es->insert (employee(i, "TestEmployee",100-i));
> > }
> > l.unlock();
> > }
> > int N;
> > employee_set* es;
> > };