>* *CPU scheduling is generally the responsibility of the operating system
>* *kernel, *NOT* Gnu Radio. What Gnu Radio does is schedule
> blocks to threads, and the execution of those threads, and CPU
> assignment is up to the kernel. In general, the kernel does a good
> job of CPU scheduling.
>* *Your problem is probably that your flow-graphs aren't optimal in some
>* *way, and thus take more system resources than they should.
Yes, I do not why it takes a lot of resources alhough I can see with
gkrellm application that my CPUs are about 50-60%, so it is not so
bad.
>* *The other issue may be your GiGE network interface might be one that
>* *isn't very good in the buffering department, and thus makes the
>* * system work *much* harder than it should handling continuous packet
>* *traffic.
>* *What bandwidth are you using? (That is, what decimation/interpolation
>* *are you using)?
I am using 30,76Mbps in the transmitter (USRP interpolation sink 104)
I am using 6,25Mbps in the receiver (USRP decimation source 512)
>* *You haven't shared much in the way of details about your flow-graph, and
>* *I suspect that's where your problem lies.
I can post my .py file which is:
from gnuradio import audio
from gnuradio import blks2
from gnuradio import gr
from gnuradio import usrp2
from gnuradio.eng_option import eng_option
from gnuradio.gr import firdes
from gnuradio.wxgui import forms
from grc_gnuradio import wxgui as grc_wxgui
from optparse import OptionParser
import wx
class top_block(grc_wxgui.top_block_gui):
def __init__(self):
grc_wxgui.top_block_gui.__init__(self, title="Top Block")
##################################################
# Variables
##################################################
self.tune_osc_dem = tune_osc_dem = 94000000
self.tune_filter = tune_filter = 75000
self.samp_rate = samp_rate = 32000
self.fm_freq_mod = fm_freq_mod = 94000000
##################################################
# Controls
##################################################
_tune_osc_dem_sizer = wx.BoxSizer(wx.VERTICAL)
self._tune_osc_dem_text_box = forms.text_box(
parent=self.GetWin(),
sizer=_tune_osc_dem_sizer,
value=self.tune_osc_dem,
callback=self.set_tune_osc_dem,
label="Tunned frequency demodulator",
converter=forms.float_converter(),
proportion=0,
)
self._tune_osc_dem_slider = forms.slider(
parent=self.GetWin(),
sizer=_tune_osc_dem_sizer,
value=self.tune_osc_dem,
callback=self.set_tune_osc_dem,
minimum=88000000,
maximum=108000000,
num_steps=800,
style=wx.SL_HORIZONTAL,
cast=float,
proportion=1,
)
self.Add(_tune_osc_dem_sizer)
_tune_filter_sizer = wx.BoxSizer(wx.VERTICAL)
self._tune_filter_text_box = forms.text_box(
parent=self.GetWin(),
sizer=_tune_filter_sizer,
value=self.tune_filter,
callback=self.set_tune_filter,
label="LPF Cutoff Freq",
converter=forms.float_converter(),
proportion=0,
)
self._tune_filter_slider = forms.slider(
parent=self.GetWin(),
sizer=_tune_filter_sizer,
value=self.tune_filter,
callback=self.set_tune_filter,
minimum=15000,
maximum=150000,
num_steps=1000,
style=wx.SL_HORIZONTAL,
cast=float,
proportion=1,
)
self.Add(_tune_filter_sizer)
_fm_freq_mod_sizer = wx.BoxSizer(wx.VERTICAL)
self._fm_freq_mod_text_box = forms.text_box(
parent=self.GetWin(),
sizer=_fm_freq_mod_sizer,
value=self.fm_freq_mod,
callback=self.set_fm_freq_mod,
label="FM frequency modulator",
converter=forms.float_converter(),
proportion=0,
)
self._fm_freq_mod_slider = forms.slider(
parent=self.GetWin(),
sizer=_fm_freq_mod_sizer,
value=self.fm_freq_mod,
callback=self.set_fm_freq_mod,
minimum=0,
maximum=110000000,
num_steps=300,
style=wx.SL_HORIZONTAL,
cast=float,
proportion=1,
)
self.Add(_fm_freq_mod_sizer)
##################################################
# Blocks
##################################################
self.audio_sink_0 = audio.sink(32000, "plughw:0,0", True)
self.blks2_fm_demod_cf_0 = blks2.fm_demod_cf(
channel_rate=320000,
audio_decim=10,
deviation=75000,
audio_pass=1000,
audio_stop=16000,
gain=20.0,
tau=75e-6,
)
self.blks2_rational_resampler_xxx_0_0 =
blks2.rational_resampler_fff(
interpolation=5,
decimation=1,
taps=None,
fractional_bw=None,
)
self.blks2_rational_resampler_xxx_1 =
blks2.rational_resampler_fff(
interpolation=4,
decimation=1,
taps=None,
fractional_bw=None,
)
self.blks2_rational_resampler_xxx_1_0_0 =
blks2.rational_resampler_ccc(
interpolation=100,
decimation=61,
taps=None,
fractional_bw=None,
)
self.gr_frequency_modulator_fc_0 =
gr.frequency_modulator_fc(0.980)
self.gr_multiply_const_vxx_1 = gr.multiply_const_vcc((32000, ))
self.gr_wavfile_source_0 =
gr.wavfile_source("/home/jorge/Desktop/outfile2.wav", True)
self.low_pass_filter_0 = gr.fir_filter_ccf(1, firdes.low_pass(
3, 320000, tune_filter, 5000, firdes.WIN_HAMMING, 6.76))
self.low_pass_filter_0_0 = gr.interp_fir_filter_fff(1,
firdes.low_pass(
1, 240000, 18e3, 2e3, firdes.WIN_HAMMING, 6.76))
self.usrp2_sink_xxxx_0 = usrp2.sink_32fc()
self.usrp2_sink_xxxx_0.set_interp(104)
self.usrp2_sink_xxxx_0.set_center_freq(fm_freq_mod)
self.usrp2_sink_xxxx_0.set_gain(0)
self.usrp2_source_xxxx_0 = usrp2.source_32fc()
self.usrp2_source_xxxx_0.set_decim(512)
self.usrp2_source_xxxx_0.set_center_freq(tune_osc_dem)
self.usrp2_source_xxxx_0.set_gain(10)
##################################################
# Connections
##################################################
self.connect((self.gr_frequency_modulator_fc_0, 0),
(self.gr_multiply_const_vxx_1, 0))
self.connect((self.blks2_rational_resampler_xxx_0_0, 0),
(self.low_pass_filter_0_0, 0))
self.connect((self.low_pass_filter_0_0, 0),
(self.blks2_rational_resampler_xxx_1, 0))
self.connect((self.gr_wavfile_source_0, 0),
(self.blks2_rational_resampler_xxx_0_0, 0))
self.connect((self.blks2_rational_resampler_xxx_1, 0),
(self.gr_frequency_modulator_fc_0, 0))
self.connect((self.usrp2_source_xxxx_0, 0),
(self.blks2_rational_resampler_xxx_1_0_0, 0))
self.connect((self.blks2_fm_demod_cf_0, 0), (self.audio_sink_0,
0))
self.connect((self.blks2_rational_resampler_xxx_1_0_0, 0),
(self.low_pass_filter_0, 0))
self.connect((self.low_pass_filter_0, 0),
(self.blks2_fm_demod_cf_0, 0))
self.connect((self.gr_multiply_const_vxx_1, 0),
(self.usrp2_sink_xxxx_0, 0))
def set_tune_osc_dem(self, tune_osc_dem):
self.tune_osc_dem = tune_osc_dem
self._tune_osc_dem_slider.set_value(self.tune_osc_dem)
self._tune_osc_dem_text_box.set_value(self.tune_osc_dem)
self.usrp2_source_xxxx_0.set_center_freq(self.tune_osc_dem)
def set_tune_filter(self, tune_filter):
self.tune_filter = tune_filter
self.low_pass_filter_0.set_taps(firdes.low_pass(3, 320000,
self.tune_filter, 5000, firdes.WIN_HAMMING, 6.76))
self._tune_filter_slider.set_value(self.tune_filter)
self._tune_filter_text_box.set_value(self.tune_filter)
def set_samp_rate(self, samp_rate):
self.samp_rate = samp_rate
def set_fm_freq_mod(self, fm_freq_mod):
self.fm_freq_mod = fm_freq_mod
self._fm_freq_mod_slider.set_value(self.fm_freq_mod)
self._fm_freq_mod_text_box.set_value(self.fm_freq_mod)
self.usrp2_sink_xxxx_0.set_center_freq(self.fm_freq_mod)
if __name__ == '__main__':
parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
(options, args) = parser.parse_args()
tb = top_block()
tb.Run(True)
Frequency sample rates are matched.
I cannot understand why changing the USRP sink interpolation affects
the FM demodulator.
They should be independent if the Ethernet traffic is under the limit.
I see a lot ot SSSSSS mesages and also audio underruns.
Many thanks for your help,
Jorge
>* *--
>* *Marcus Leech
>* *Principal Investigator
>* *Shirleys Bay Radio Astronomy Consortium>* *http://www.sbrac.org
><http://www.sbrac.org/>
>* Hi all!*
>
>* I am Tx/Rx a FM signal at the same time, but I can see a lot of SSSSS*
>* messages that mean my CPU cannot keep up with all frames generated by*
>* the USRP2 and drop most of them.*
>* However I have a quite new laptop with a CPU:Intel(R) Core(TM) i5*
>* CPU M 520 @ 2.40GHz on Ubuntu 10.4*
>
>* I guess that my laptop is enough to run my FM Tx/Rx and I wonder if I*
>* can balance the workload among all my four cores to see if my*
>* application improves (ethernet interface doens't drop any frame).*
>
>* Looking at other post of the mailing list I found:*
>
>* 1)"Try using numactl".*
>* Well, for me is not possible, after installing that library and running:*
>* :~$ numactl -s*
>* physcpubind: 0 1 2 3*
>* No NUMA support available on this system.*
>
>* 2)"Look at the output of cat /proc/cpuinfo "physical id" indicates*
>* which cores are in which sockets"*
>* In all four processors physical id : 0*
>
>* Furthermore whe I execute top command I can see:*
>* PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND *
>* 3022 root 20 0 238m 66m 45m S 166 3.6 *
>* 3:32.12 python*
>
>
>* Is my GRC file only executing in one core? How can I find it out?*
>* Any idea to fix it?*
>
>* Many thanks,*
>* Jorge*
>
>
>* *
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