Re: [Discuss-gnuradio] Question about UHD driver

[Mark McCarron]

Guys,

This places a limit on the performance of GNURadio that can be avoid through a push for a more modern type of DMA.

The ideal scenario is to never copy data and it is achievable, to a degree, through proper planning.   If you look at your argument, you are essentially saying that it is better to copy than to have a pointer.

I can't agree with that.

Regards,

Mark McCarron

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From: address@hidden
Date: Fri, 17 May 2013 10:06:08 -0700
Subject: Re: [Discuss-gnuradio] Question about UHD driver
To: address@hidden
CC: address@hidden

On Fri, May 17, 2013 at 9:55 AM, Mark McCarron <address@hidden> wrote:

 

In order to support massive parallelism, data must be duplicated as it comes of the wire and into memory.  Not duplicated in FIFO streams in an application.

There is no duplication of buffer contents in GNU Radio.

To elaborate on what Matt Ettus described earlier, GNU Radio blocks are connected via single-producer, multi-consumer FIFOs.  Upstream blocks (including hardware source blocks) write into the FIFO, and multiple concurrently running downstream-connected blocks have read-only access to its contents, while writing the output of their individual DSP functions into new FIFOs for the next stages of the pipeline.

There is no need to pre-copy the data into different memory areas for multiple consumers to access, and no need to worry that processing in one block has any side effects on processing in another block.

--
Johnathan Corgan
Corgan Labs - SDR Training and Development Services
http://corganlabs.com