Re: [Discuss-gnuradio] FX2 firmware

[Marcus D. Leech]

Dominik Auras wrote:
>
> When doing RX only, I am at 45 Mb/s (yes! decim=6 works without
> underruns). On the TX side, I can't get above 32.7 Mb/s. Now I suspect
> that this is a host side bottleneck. On the FX2, if using only one
> direction, I am setting the GPIF to loop infinitely. With
> GPIFABORT=0xFF to switch if the state changes. Hence there is no main
> loop left that could be a bottleneck. The TX state machine now
> consists of 2 states, where state one is the idle state, and state 2
> transferring data (one word per clock, as before). The 8051 core is
> completely out of the data path. (Auto commit etc.)
> Same for RX, except that a few more states were needed.
Hmmm.  My application is RX-only.   Using 8-bit samples, that 45Mb/s
gives about 20Msps.    I have a QX9770 system running
  at 3.7GHz, but *still* get overruns at two channels, 8Msps per
(complex) channel.  I also get overruns at 16Msps, single-channel.

At 8Msps dual-channel, my application (an all-mode radio astronomy
receiver system) burns up about 2.75CPU on the above-mentioned
  address@hidden (with slower memory that will get upgraded soon!).   I
get overruns a couple of times per minute with this
  setup.

What type of system are you getting reliable 45Mb/s receive throughput
on, and how complicated is your signal processing
  flowgraph?

-- 

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