[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Discuss-gnuradio] Request for comment: FFT optimizations

From: Albin Stigö
Subject: [Discuss-gnuradio] Request for comment: FFT optimizations
Date: Thu, 6 Jun 2019 11:13:43 +0200


There's a lot of memcpy/memmove going on in the FFT kernel which I
suspect degrades performance quite a bit... This is partly because
some platforms requires buffers to be aligned for SIMD to work and
partly because DC is not normally centered (which is normally what you
would like to see in a spektrum).

For ARM in particular the alignment requirements are less strict so
that would get rid of at least one memcpy for that platform.

For centering an FFT at DC there's a nice trick, you just rotate the
input by pi, that is multiply by 1, -1, 1, -1... I suspect that would
be quite a bit faster than two memcpy and should be available on all

Has this been discussed on the list before?


reply via email to

[Prev in Thread] Current Thread [Next in Thread]