Re: [Discuss-gnuradio] How to balance workload among cores? Laptop cannot keep up with the USRP2 data flow.
Tom, This doesn't sound like a performance issue. I absolutely agree. I think you're probably looking at a sample rate mismatch somewhere. If it were the case. Don´t you think that FM transmitter by itself and FM receiver by itself shouldn´t work neither? The point is that both of them when running alone work. That is the fact I do not understand. Regards, Jorge. On 2 October 2010 17:03, Tom Rondeau trondeau1...@gmail.com wrote: On Thu, Sep 30, 2010 at 5:52 AM, Jorge Miguel jmig...@gmail.com wrote: Hi ! Eric, thanks for your advise. Some results here. I set my computer into performance mode. At first sight nothing improves. With the example usrp2_fft.py I can low the decimation to 5 and the application works ok. As I said the FM modulator works ok by itself. The FM demodulator also works ok by itself. The problem is when I run both in the same flowgraph. I think it is not a problem of performance since my CPUs are not very work-loaded when my application is running. My problem is that changes, in the FM modulator, which I think they would increase performance (like increasing my 13 interpolation in the USRP and decreasing my software interpolation) make my receiver chain non-working (SSS messages) although the transmitter outputs a perfect FM signal. I do not understand these mesages since my CPUs are less than 15-20% used. However something is stopping the received data because I got a lot of dropped frames in my rx Ethernet interface (saw with ifconfig). I tried to increase the RX Ethernet buffer (sysctl -w net.core.rmem_max=X) but it didn't work. I also tried to set in my generated code the USRP source instance before the USRP sink but it didn't work neither. Could be any reason why by decreasing software computation (and Ethernet traffic as well) in the transmitter path affects the performance of the RX path? Many thanks, Jorge. This doesn't sound like a performance issue. I think you're probably looking at a sample rate mismatch somewhere. Tom ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] How to balance workload among cores? Laptop cannot keep up with the USRP2 data flow.
Hi ! Eric, thanks for your advise. Some results here. I set my computer into performance mode. At first sight nothing improves. With the example usrp2_fft.py I can low the decimation to 5 and the application works ok. As I said the FM modulator works ok by itself. The FM demodulator also works ok by itself. The problem is when I run both in the same flowgraph. I think it is not a problem of performance since my CPUs are not very work-loaded when my application is running. My problem is that changes, in the FM modulator, which I think they would increase performance (like increasing my 13 interpolation in the USRP and decreasing my software interpolation) make my receiver chain non-working (SSS messages) although the transmitter outputs a perfect FM signal. I do not understand these mesages since my CPUs are less than 15-20% used. However something is stopping the received data because I got a lot of dropped frames in my rx Ethernet interface (saw with ifconfig). I tried to increase the RX Ethernet buffer (sysctl -w net.core.rmem_max=X) but it didn't work. I also tried to set in my generated code the USRP source instance before the USRP sink but it didn't work neither. Could be any reason why by decreasing software computation (and Ethernet traffic as well) in the transmitter path affects the performance of the RX path? Many thanks, Jorge. On 28 September 2010 05:43, Eric Blossom e...@comsec.com wrote: On Mon, Sep 27, 2010 at 10:07:07AM +0200, Jorge Miguel wrote: Hi all! I am Tx/Rx a FM signal at the same time, but I can see a lot of S 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). First off, you don't really have 4 cores. You've got 2 cores + hyperthreading (they may have renamed it, but that's what you've got). GNU Radio will automatically use whatever you've got, without you having to do anything special. Be sure that your laptop is in Performance mode, and not trying to save energy, or throttle back etc. There are also some laptops out there that have poor thermal design and can't really run at full speed without overheating and thus throttling back the CPU. Start with something like usrp_fft.py and see how low of a decimation factor you can work with reliably. That will give you a basic idea of how your system is working. If you're building your own flow graphs, it's quite easy to string together more blocks, or use a a higher sample rate, than your machine can keep up with. After you've ruled out the stuff above, oprofile will help you sort out which parts of your application are burning the most time. Eric ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] How to balance workload among cores? Laptop cannot keep up with the USRP2 data flow.
Hi all! I am Tx/Rx a FM signal at the same time, but I can see a lot of S 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 %MEMTIME+ 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 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] How to balance workload among cores? Laptop cannot keep up with the USRP2 data flow.
Hi all! I am Tx/Rx a FM signal at the same time, but I can see a lot of S 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 %MEMTIME+ 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 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. 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)? You haven't shared much in the way of details about your flow-graph, and I suspect that's where your problem lies. -- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] How to balance workload among cores? Laptop cannot keep up with the USRP2 data flow
* *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 = 9400 self.tune_filter = tune_filter = 75000 self.samp_rate = samp_rate = 32000 self.fm_freq_mod = fm_freq_mod = 9400 ## # 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=8800, maximum=10800, 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=15, 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,
Re: [Discuss-gnuradio] How to balance workload among cores? Laptop cannot keep up with the USRP2 data flow.
On Mon, Sep 27, 2010 at 10:07:07AM +0200, Jorge Miguel wrote: Hi all! I am Tx/Rx a FM signal at the same time, but I can see a lot of S 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). First off, you don't really have 4 cores. You've got 2 cores + hyperthreading (they may have renamed it, but that's what you've got). GNU Radio will automatically use whatever you've got, without you having to do anything special. Be sure that your laptop is in Performance mode, and not trying to save energy, or throttle back etc. There are also some laptops out there that have poor thermal design and can't really run at full speed without overheating and thus throttling back the CPU. Start with something like usrp_fft.py and see how low of a decimation factor you can work with reliably. That will give you a basic idea of how your system is working. If you're building your own flow graphs, it's quite easy to string together more blocks, or use a a higher sample rate, than your machine can keep up with. After you've ruled out the stuff above, oprofile will help you sort out which parts of your application are burning the most time. Eric ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
