Re: [Discuss-gnuradio] WX GUI FFT Sink Performance

[Mark McCarron]

Marcus,

I have run some tests and it looks like the WX GUI FFT Sink stops responding with any settings above address@hidden FPS.

I've upgrade my video card drivers and they work fine with everything else.  Processor usage is fine, nothing in the event logs.

Regards,

Mark McCarron

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From: address@hidden
To: address@hidden
Subject: RE: [Discuss-gnuradio] WX GUI FFT Sink Performance
Date: Thu, 16 May 2013 06:21:34 +0100

Marcus,

Sorry for the late reply on this, I've been upgrading my hardware and I'm just catching up.  Here is my issue, in Spectrum lab if I provide a FFT Input length of 65536 on a 192Ksps stream, I get the following characteristics:

Effect of FFT settings with fs= 192.000 kHz:
Width of one FFT-bin: 2.92969 Hz
Equiv. noise bandwidth: 4.39453 Hz
Max freq range: 0.00000 Hz .. 96.0000 kHz
FFT window time: 0.341 s
Overlap from scroll interval: 98.4 %

It runs quite fast.  If I provide the same FFT size to WX GUI FFT sink, it basically hangs.  Do you know why?

Regards,

Mark McCarron

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Date: Sat, 11 May 2013 15:59:18 -0400
From: address@hidden
To: address@hidden; address@hidden
Subject: Re: [Discuss-gnuradio] WX GUI FFT Sink Performance

I figured that one out, but why is the performance so poor?

In other applications, I can push over half a million samples without causing issues.

Regards,

Mark McCarron

Your OpenGL implementation may suck.  

What sample rate are you using?

If it's quite a low rate, then with a large number of bins, there may be no way to achieve the given frame rate, given the sample rate, and FFT size.

-- 
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org