Re: [Discuss-gnuradio] Optimal way of performing multiple FFTs on a stream of data

[Tom Rondeau]

On Thu, Sep 30, 2010 at 2:54 PM, John Andrews <address@hidden> wrote:
> Thanks Eric. My FFTs are not that big so I guess I will be fine.

Yeah, FFT's are extremely efficient. In fact, sometimes larger is
better. If you're doing really small FFTs on the order or 16 or 32,
you might be able to get better performance by doing at 64 point FFT,
instead. Of course, measuring is the only way to know for sure.

My guess is you aren't doing FFTs that small, so just stick with the
normal approach and, like Eric said, save the optimization for later
if you need it.

Tom



> On Wed, Sep 29, 2010 at 4:59 PM, Eric Blossom <address@hidden> wrote:
>> I'd measure first, and see if you've really got a problem.
>> (Premature optimization is the root of all evil.)
>>
>> Note also that GNU Radio itself is multithreaded, and if you're doing
>> substantial work in other blocks, your cores may already being put to
>> productive work.
>>
>> Make sure that the version of FFTW you're using was built with SSE
>> support enabled.
>>
>>  http://fftw.org/fftw3_doc/Installation-on-Unix.html
>>
>>  ./configure --enable-sse --enable-float
>>
>> Measure again :-)