A few things to observe about it:
o The virtual size of this thing in execution is *elephantine* o Manipulating it inside GRC is really, really, really, painfulo Running it above 10Msps causes UHD to silently stop sending data (or maybe it never gets started) o Running it at 5Msps or slower, and it works, although it's still elephantine
So, yeah, the FFT is big, but I tried different sized FFTs from 32768 upwards, and I still see the behaviour that at 10Msps or above, I get *no data* (after a loooong pause while Gnu Radio does some cogitation, presumably in (elephantine) buffer setup).
Now this flow-graph (actually a more-complex version of it) used to work, even at 10Msps, up to about 3 weeks ago, when I updated
UHD and Gnu Radio. Some perhaps useful data points: o 6-core AMD 1090T at 3.2GHz with 4GB of 1333MHz memory o I'm using gr_vmcircbuf_mmap_shm_open_factory o The very latest UHD and Gnu Radio o USRP2 + WBXI'll make the observation that there's just got to be a better buffer allocation policy than the existing one. Should it *really* take Gigabytes of VM, and hundreds of MB of RSS to execute the flow-graph I've attached? The largest inter-block objects--the vectors in front of and behind the FFT, are on the order of a few MB, and even accounting for some ballooning factor so you can have several such vectors "in flight", that doesn't add up to hundreds of MB of RSS, and several GB of Virtual Size.
-- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org
uhd_test_ra_receiver.grc
Description: application/gnuradio-grc
#!/usr/bin/env python
##################################################
# Gnuradio Python Flow Graph
# Title: Integrated Radio Astronomy Receiver--test graph
# Author: Marcus Leech
# Description: gnuradio flow graph
# Generated: Wed Jun 29 00:24:15 2011
##################################################
from gnuradio import eng_notation
from gnuradio import gr
from gnuradio import uhd
from gnuradio import window
from gnuradio.eng_option import eng_option
from gnuradio.gr import firdes
from gnuradio.wxgui import fftsink2
from grc_gnuradio import wxgui as grc_wxgui
from optparse import OptionParser
import wx
class uhd_test_ra_receiver(grc_wxgui.top_block_gui):
def __init__(self, freq=1420.4058e6, gain=55, ratepsr=50000, bandwidth=10.0e6, devaddr="addr=192.168.10.2", setisize=65536*4):
grc_wxgui.top_block_gui.__init__(self, title="Integrated Radio Astronomy Receiver--test graph")
##################################################
# Parameters
##################################################
self.freq = freq
self.gain = gain
self.ratepsr = ratepsr
self.bandwidth = bandwidth
self.devaddr = devaddr
self.setisize = setisize
##################################################
# Variables
##################################################
self.seti_rate = seti_rate = 5
##################################################
# Blocks
##################################################
self.wxgui_fftsink2_0 = fftsink2.fft_sink_c(
self.GetWin(),
baseband_freq=freq,
y_per_div=10,
y_divs=10,
ref_level=50,
ref_scale=2.0,
sample_rate=bandwidth,
fft_size=1024,
fft_rate=10,
average=True,
avg_alpha=0.250,
title="FFT Plot",
peak_hold=False,
)
self.Add(self.wxgui_fftsink2_0.win)
self.uhd_usrp_source_0 = uhd.usrp_source(
device_addr=devaddr,
io_type=uhd.io_type.COMPLEX_FLOAT32,
num_channels=1,
)
self.uhd_usrp_source_0.set_samp_rate(bandwidth)
self.uhd_usrp_source_0.set_center_freq(freq, 0)
self.uhd_usrp_source_0.set_gain(gain, 0)
self.gr_stream_to_vector_0 = gr.stream_to_vector(gr.sizeof_gr_complex*1, int(setisize))
self.gr_single_pole_iir_filter_xx_1 = gr.single_pole_iir_filter_ff(1.0/(bandwidth/setisize), int(setisize))
self.gr_single_pole_iir_filter_xx_0 = gr.single_pole_iir_filter_ff(1.0/(bandwidth/(ratepsr/2.0)), 1)
self.gr_keep_one_in_n_1 = gr.keep_one_in_n(gr.sizeof_float*int(setisize), int(bandwidth/setisize)/seti_rate)
self.gr_keep_one_in_n_0 = gr.keep_one_in_n(gr.sizeof_float*1, int(bandwidth/ratepsr))
self.gr_file_sink_1 = gr.file_sink(gr.sizeof_float*1, "/dev/null")
self.gr_file_sink_1.set_unbuffered(True)
self.gr_file_sink_0_0 = gr.file_sink(gr.sizeof_float*int(setisize), "/dev/null")
self.gr_file_sink_0_0.set_unbuffered(True)
self.gr_fft_vxx_0 = gr.fft_vcc(int(setisize), True, (window.blackmanharris(int(bandwidth))), False)
self.gr_complex_to_mag_squared_0 = gr.complex_to_mag_squared(1)
self.gr_complex_to_mag_0 = gr.complex_to_mag(int(setisize))
##################################################
# Connections
##################################################
self.connect((self.gr_stream_to_vector_0, 0), (self.gr_fft_vxx_0, 0))
self.connect((self.gr_fft_vxx_0, 0), (self.gr_complex_to_mag_0, 0))
self.connect((self.gr_single_pole_iir_filter_xx_0, 0), (self.gr_keep_one_in_n_0, 0))
self.connect((self.gr_complex_to_mag_squared_0, 0), (self.gr_single_pole_iir_filter_xx_0, 0))
self.connect((self.gr_keep_one_in_n_0, 0), (self.gr_file_sink_1, 0))
self.connect((self.gr_complex_to_mag_0, 0), (self.gr_single_pole_iir_filter_xx_1, 0))
self.connect((self.gr_single_pole_iir_filter_xx_1, 0), (self.gr_keep_one_in_n_1, 0))
self.connect((self.gr_keep_one_in_n_1, 0), (self.gr_file_sink_0_0, 0))
self.connect((self.uhd_usrp_source_0, 0), (self.wxgui_fftsink2_0, 0))
self.connect((self.uhd_usrp_source_0, 0), (self.gr_complex_to_mag_squared_0, 0))
self.connect((self.uhd_usrp_source_0, 0), (self.gr_stream_to_vector_0, 0))
def get_freq(self):
return self.freq
def set_freq(self, freq):
self.freq = freq
self.wxgui_fftsink2_0.set_baseband_freq(self.freq)
self.uhd_usrp_source_0.set_center_freq(self.freq, 0)
def get_gain(self):
return self.gain
def set_gain(self, gain):
self.gain = gain
self.uhd_usrp_source_0.set_gain(self.gain, 0)
def get_ratepsr(self):
return self.ratepsr
def set_ratepsr(self, ratepsr):
self.ratepsr = ratepsr
self.gr_keep_one_in_n_0.set_n(int(self.bandwidth/self.ratepsr))
self.gr_single_pole_iir_filter_xx_0.set_taps(1.0/(self.bandwidth/(self.ratepsr/2.0)))
def get_bandwidth(self):
return self.bandwidth
def set_bandwidth(self, bandwidth):
self.bandwidth = bandwidth
self.gr_keep_one_in_n_1.set_n(int(self.bandwidth/self.setisize)/self.seti_rate)
self.gr_keep_one_in_n_0.set_n(int(self.bandwidth/self.ratepsr))
self.gr_single_pole_iir_filter_xx_0.set_taps(1.0/(self.bandwidth/(self.ratepsr/2.0)))
self.wxgui_fftsink2_0.set_sample_rate(self.bandwidth)
self.uhd_usrp_source_0.set_samp_rate(self.bandwidth)
self.gr_single_pole_iir_filter_xx_1.set_taps(1.0/(self.bandwidth/self.setisize))
def get_devaddr(self):
return self.devaddr
def set_devaddr(self, devaddr):
self.devaddr = devaddr
def get_setisize(self):
return self.setisize
def set_setisize(self, setisize):
self.setisize = setisize
self.gr_keep_one_in_n_1.set_n(int(self.bandwidth/self.setisize)/self.seti_rate)
self.gr_single_pole_iir_filter_xx_1.set_taps(1.0/(self.bandwidth/self.setisize))
def get_seti_rate(self):
return self.seti_rate
def set_seti_rate(self, seti_rate):
self.seti_rate = seti_rate
self.gr_keep_one_in_n_1.set_n(int(self.bandwidth/self.setisize)/self.seti_rate)
if __name__ == '__main__':
parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
parser.add_option("", "--freq", dest="freq", type="eng_float", default=eng_notation.num_to_str(1420.4058e6),
help="Set freq [default=%default]")
parser.add_option("", "--gain", dest="gain", type="eng_float", default=eng_notation.num_to_str(55),
help="Set gain [default=%default]")
parser.add_option("", "--ratepsr", dest="ratepsr", type="eng_float", default=eng_notation.num_to_str(50000),
help="Set ratepsr [default=%default]")
parser.add_option("", "--bandwidth", dest="bandwidth", type="eng_float", default=eng_notation.num_to_str(10.0e6),
help="Set None [default=%default]")
parser.add_option("", "--devaddr", dest="devaddr", type="string", default="addr=192.168.10.2",
help="Set devaddr [default=%default]")
parser.add_option("", "--setisize", dest="setisize", type="intx", default=65536*4,
help="Set setisize [default=%default]")
(options, args) = parser.parse_args()
tb = uhd_test_ra_receiver(freq=options.freq, gain=options.gain, ratepsr=options.ratepsr, bandwidth=options.bandwidth, devaddr=options.devaddr, setisize=options.setisize)
tb.Run(True)
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