[Discuss-gnuradio] GNURadio retrictions

[Mostafa Alizadeh]

Hello GNURadioers!

I've been working with GNURadio since about one year ago. I just figured out the following limitation of GNURadio's framework that I want to diacuss them to clarify whether I'm wrong or not:

1- For general blocks with multiple output ports, there is a problem with the amount of producing items when the general work routine just gives you the "maximum" available number of output items for all output ports, and also set_output_multiple or other functions like set_alignment dealing with all output ports rather than individual ones. So if one wants to produce items on the output ports with large different numbers, such as 100 items on one port and 2000 items on the other one, the scheduler will fail to manage this high "diverse" ports.

2- The scheduler jumps through different blocks before finishing the work routine's job which causes some problems. For example, consider the below code which is placed somewhere in the work (general_work ):

"""""""""""""""""
memcpy (out, temp, n_out_produced * sizeof(gr_complex);

produce(0, n_out_produced);

add_item_tag(0, nitems_written(0), ... , ... );
"""""""""""""""""

So if we change the order of the code like this:

"""""""""""""""""
memcpy (out, temp, n_out_produced * sizeof(gr_complex);

add_item_tag(0, nitems_written(0), ... , ... );

produce(0, n_out_produced);
"""""""""""""""""

In the second case there is no problem with tagging process, although in the first case the scheduler may jump out of this block right after calling produce function, so the position of the tagging which is " nitems_written(0)" will change to the new value. Suppose in the next call to the first code, after calling produce function, the add_item_tag is called and the item is tagged on "nitems_written(0)" position which is the same as the previous call. So these two consecutive tags are placed on the same position in the stream. Why is this happening? This is just because before finishing the job of this work routine, scheduler jumps somewhere else.

Please help me find the rational reason!

Thanks in advance,
Alizadeh