Re: [Discuss-gnuradio] buffer size 32k

[Charles Swiger]

On Wed, 2006-07-05 at 09:39 -0700, Eric Blossom wrote:
> On Wed, Jul 05, 2006 at 11:25:55AM -0400, Chuck Swiger wrote:
> > I'm curious about this statement in
> > $PYTHONPATH/gnuradio/gr/flow_graph.py
> > 
> >         # We could scan the graph here and determine individual sizes
> >         # based on relative_rate, number of readers, etc.
> > 
> > 
> > In the meantime, it would be nice to be able, somehow, to tweak the
> > global buffer size from inside an application, without having to
> > edit flow_graph.py manually. Or a GR_BUF_SIZE environment variable.
> > 
> > Because: One of my simple test apps works 600% faster using 4k buffer
> > instead of 32k, since it doesn't have to wait for stale data to clear.
> 
> Chuck, can you point me at the code for the application?
> I wouldn't expect the size of buffer to matter as long as each block
> returned all the data asked for on each call to work.
> 

No biggie in the grand scheme, for one particular app with lots of
fg starting and stopping here's two plots with the only change being
self.fixed_buffer_size = 32*1024 or 4*1024:

4k buffer:

http://webpages.charter.net/cswiger/80m_filter_4kbuf.jpg

nice, smooth and fast - 10 data points per second. But with
default 32k buffer:

http://webpages.charter.net/cswiger/80m_filter_32kbuf.jpg

no good. That's where I had to slow it down to 3/4 second per
data point (bletch).