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Re: [Discuss-gnuradio] FX2 firmware
From: |
Marcus D. Leech |
Subject: |
Re: [Discuss-gnuradio] FX2 firmware |
Date: |
Wed, 06 May 2009 15:46:19 -0400 |
User-agent: |
Thunderbird 2.0.0.19 (X11/20090105) |
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