Re: [Discuss-gnuradio] FIFO latency

[Marcus D. Leech]

On 05/28/2011 04:28 PM, Alexander Chemeris wrote:
> > So, while this method is simple and good for non-realtime
> > applications, it doesn't fit our needs. It may be usable for PHY<->MAC
> > interaction, but even here I'm not sure it would work well.
> >
> > PS I test on Core 2 Duo 1.6 GHz with all the GUI stuff running.
> Ok, setting CPU affinity and cutting off startup artifacts definitely helps.
> Results are in attachment.
> Still you can see quite some uncertainty.
OK, so a roughly 3:1 improvement in peak latency, and somewhat better 
predicability.

But I'd still counter-assert, to your assertion, that latencies in the 
10s-of-usec are entirely acceptable for
  a wide-range of "real-time" applications, even with occasional 
latency excursions that increase the variability
  by 50:1 or so.

I can well imagine that they aren't acceptable for *your* application.  
I mean, if all applications were the same, it would
  be a very boring world, with most of us working at fast-food 
restaurants :-)

But I'll stand by my original suggestion that use of FIFOs are an 
acceptable technique for a wide variety of applications, including
  "real-time" applications, depending on constraints and requirements.



--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org