Re: [Discuss-gnuradio] Running out of memory during BER simulations

[Marcus Müller]

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Hi Felix,


On 11/25/2014 06:15 PM, Felix W. wrote:
> Between every run, I call tb.stop() followed by tb.wait().
> Unfortunately, after a few runs (around 20), I get the following
> error message:
> 
> gr::vmcircbuf_sysv_shm: shmget (2): No space left on device
I have a suspicion.
First of all, I know this sounds basic, but you're not using a 32bit
GR on your 64 bit machine, are you? (that would explain running out of
RAM faster, just because process memory is so very limited for 32bit
processes)

then: vmcircbuf is one of the things I always was kind of hesitant to
touch (or even try to understand in depth), just because it deals with
a lot of POSIX/OS specifics that I'm not an expert in, but:

Maybe tb.stop()/wait doesn't actually successfully unmap the shared
memory segments of the buffers; there's a global maximum of segments,
and it 4096 by default (/proc/sys/kernel/shmmni). However, this
shouldn't be the problem at hand: there's an error number for this
condition. And it would be: ENOSPC. Great. The same thing as for "No
space left on device"; Thank you, Posix.1...

Cheers,
Marcus
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