Re: [Discuss-gnuradio] Strange output of "0" at the terminal

[Wu Ting]

Hi! Thank you for your response. I've kept working on this problem for two
days, but still cannot find a way to solve it.

I simplified the program and have determined that the 'O' is produced is
this while loop:

while msgCount<10000:
    msg = tb.queue.delete_head()
    payload = msg.to_string()
    f.write(payload)
    msgCount += 1

I also tried to make it sleep for a short time after each operation:

while msgCount<10000:
    msg = tb.queue.delete_head()
    sleep(0.00001)
    payload = msg.to_string()
    sleep(0.00001)
    f.write(payload)
    sleep(0.00001)
    msgCount += 1

It still has the problem. I'm using a USRP source with 4M smapling rate, and
connect it with message_sink.

self.source = uhd.usrp_source(device_addr="",
stream_args=uhd.stream_args('sc16', 'sc16', args="scalar=1024"))
self.source.set_samp_rate(4e6)
self.queue = gr.msg_queue()
self.sink = gr.message_sink(gr.sizeof_short*2, self.queue, False)
self.connect(self.source, self.sink)

This is really a serious problem for our application because we want to
continuously record some data. Does anyone has any idea how to deal with
this problem, or at least catch this error when it happens? Any suggestions
will be greatly appreciated.

Wu

-----Original Message-----
From: Andrew Davis [mailto:address@hidden 
Sent: 2012年2月23日 0:15
To: Wu Ting; address@hidden
Subject: Re: [Discuss-gnuradio] Strange output of "0" at the terminal

"O" means there has been an overflow, some part of your system is not fast
enough to keep up with the incoming data, probably your hard drive, or you
may not have a fast enough CPU to process as the sample rate you have
chosen.

2012/2/22 Wu Ting <address@hidden>:
> The output is “O” (Oh) not “0” (zero).
>
>
>
> I made more tests and feel the problem may be from use of write() to 
> write data into files. Anyone had similar problem?
>
>
>
> Wu
>
>
>
> From: 
> address@hidden
> [mailto:discuss-gnuradio-bounces+wu.ting=comf5.comm.eng.osaka-u.ac.jp@
> gnu.org]
> On Behalf Of Wu Ting
> Sent: 2012年2月22日 14:48
> To: address@hidden
> Subject: [Discuss-gnuradio] Strange output of "0" at the terminal
>
>
>
> Hi all,
>
>
>
> I’m now using message_sink and msg_queue to receive data from USRP. I 
> do some calculation for all the data in the msg_queue one by one and 
> write some of them into a file. Everything seems to be working 
> smoothly. But once in a while, a “0” is printed in the terminal. 
> (There is no code to print “0” in my program.) I checked the data, and 
> found that every time a “0” is printed, some data are lost, and the 
> length of lost data seems to be of hundreds of messages.
>
>
>
> There is no other error information, so I’m really confused by this
problem.
> Does anyone has a clue of what happened and how should I deal with it?
>
>
>
> Thanks,
>
>
>
> Wu
>
>
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