Re: [Discuss-gnuradio] Parallel programming

[Michael Dickens]

Assuming you're using a reasonably recent GIT checkout, then your flow-graph 
should be executing in "thread per block" mode by default -- each block you 
create in your flow-graph will reside in its own unique thread.  You can 
manually override this setting to be in "single threaded scheduler" mode 
instead, where all blocks are executed within a single thread in a round-robin 
fashion (roughly; no need for its complexities here).  Those are your 2 choices 
when using GNU Radio (without rewriting the scheduler yourself).  IIRC the 
latter (STS) is being deprecated "real soon now" -- someone please correct me 
if I'm remembering incorrectly.

Generally, you shouldn't need to further parallelize beyond what's already 
provided.  A specific case where one would want do add another thread is when 
data must be transferred non-synchronously (e.g., async or isync) -- for 
example, the native USB driver for Mac OS X spawns a new thread to handle the 
OS-interface part.  Otherwise, you can probably find a clever way to create a 
"meta-block" that encloses a number of actual blocks, and then let the "thread 
per block" scheduler handle them.  GNU Radio uses Intel's TBB already, so if 
you feel for some reason that your particular block(s) need more 
parallelization, then that's probably the best way to go.

My US$0.02, for what it's worth. - MLD

On Jan 10, 2011, at 10:52 AM, sirjanselot wrote:
> I've been writing my own signal processing blocks and I noticed that
> gnuradio only uses one of my cores.
> 
> I'm not sure if it is using just one core for my blocks or for all
> processing.
> 
> Is gnuradio written to take advantage of  multicore processing?
> 
> I have been writing my blocks in generic c++ code, but now I am looking to
> write my blocks using multithreading/multicore processing.  However, I am
> new to this and would like some advice on how to approach this.  
> 
> I have an Intel 8-Core Xenon in my PC (I don't know the exact model but I
> believe the clock rate works around 2.8 Ghz).  What libraries should I use? 
> I have been looking into Intel Thread Building Blocks, but I am wondering
> what people mainly use for gnuradio.