queue_node is slow

[vishketan]

Hi

I am new to Intel TBB, and am trying to write some code which uses a flow graph.

I have a reader class to read data from a file which I want to queue using a buffer (there are other classes which read data from this buffer and process it). Here is what I tried:

[cpp]graph g; data_source the_source(g, reader(p, db, iter, cont), false); data_pool the_data_pool(g); try { task_scheduler_init init(p.num_threads); make_edge(the_source, the_data_pool); tick_count begin=tick_count::now(); the_source.activate(); g.wait_for_all(); tick_count end=tick_count::now(); cout << (end-begin).seconds() << "seconds " << endl; } catch(std::exception& e) { cerr<<"error occurred. error text is :"" <

data_pool is a queue_node. This takes about 7 seconds to read a file with 100,000 lines.

The reader only takes around 3 - 3.5 seconds. I verified this by using the following code:

[cpp]graph g; data_pool the_data_pool(g); reader r(p, db, iter, cont); size_t idx; while(r(idx)){ } [/cpp]

To confirm that it is the queing that is taking up more time I used the following code:

[cpp]
[/cpp][cpp]graph g; data_pool the_data_pool(g); reader r(p, db, iter, cont); size_t idx; while(r(idx)){ the_data_pool.try_put(idx); the_data_pool.try_consume(); }[/cpp]

and sure enough the time doubles. I am wondering why merely queing up data takes up so much time.

Please ask if you need any other information. I am using the tbb installed by macports

tbb @4.0-20120201 (devel)

thanks

vishy