Re: [Discuss-gnuradio] Manager for blob and message passing - Blocking in E110

[Josh Blum]

On 11/26/2012 10:11 PM, Jose Torres Diaz wrote:
> Hi All,
> 
> I'm still doing some blocks using message passing technique. Now, I'm
> working with blob passing downstream, however, my code blocks if I run a
> infinite loop. Before, I had some issues with memory blowing out (using PMT
> dictionaries), but using the pmt manager solves the problem.
> 
> My code is quite easy, but it does not runs infinitely in E110.
> 
> BLOCK 1 (Source of Blobs)   -------- >  BLOCK 2 (Count the number of Blobs
> received)
> 
> *BLOCK 1 - Source:*
> This is the source block and it is similar to stream to blob. I'm creating
> a pool of 17 blobs with size 1500 bytes. I added some data into it and then
> posting downstream.
> 
> *BLOCK 2 - Counter:
> *It counts the number of blobs received.
> 
> Running this in the E110 does it only 1000 times (in an infinite loop). I
> checked the memory usage and it looks stable all the time. I read in
> https://github.com/guruofquality/grextras/wiki:
> 
> "Normally, a PMT is created and passed to a downstream consumer. When all
> downstream consumers delete their references to the PMT, the object is
> deconstructed and freed back into nothingness. With the PMT manager, rather
> than being deconstructed, the PMT will return to the manager, where the
> user can reuse the deleted PMT without re-allocation."
> 
> When it is mention the consumer deleting their reference to the PMT, should
> I do it into my work function in BLOCK 2? or is it done automatically by
> the manager?.

The PMTs are reference counted. When BLOCK2 work() function consumes the
input, the scheduler will delete the PMT references in BLOCK2. Then, the
manager see a reference count of 1, allowing BLOCK1 to use the
allocation again. So its automatic.

-josh

> 
> Thanks for your help and directions,
> 
> Regards ,
> 
> Jose.
> 
> 
> 
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