On Fri, Dec 21, 2018 at 06:09:50PM +0800, Steven Liu wrote:
> Before patch:
> init nbits = 17, get 10000 samples, average cost: 16105 us
> After patch:
> init nbits = 17, get 10000 samples, average cost: 15221 us
>
> Signed-off-by: Steven Liu <l...@chinaffmpeg.org>
> ---
> libavcodec/fft_template.c | 26 +++++++++++++++-----------
> 1 file changed, 15 insertions(+), 11 deletions(-)
>
> diff --git a/libavcodec/fft_template.c b/libavcodec/fft_template.c
> index 762c014bc8..2b528be882 100644
> --- a/libavcodec/fft_template.c
> +++ b/libavcodec/fft_template.c
> @@ -261,17 +261,21 @@ av_cold int ff_fft_init(FFTContext *s, int nbits, int
> inverse)
> if (s->fft_permutation == FF_FFT_PERM_AVX) {
> fft_perm_avx(s);
> } else {
> - for(i=0; i<n; i++) {
> - int k;
> - j = i;
> - if (s->fft_permutation == FF_FFT_PERM_SWAP_LSBS)
> - j = (j&~3) | ((j>>1)&1) | ((j<<1)&2);
> - k = -split_radix_permutation(i, n, s->inverse) & (n-1);
> - if (s->revtab)
> - s->revtab[k] = j;
> - if (s->revtab32)
> - s->revtab32[k] = j;
> - }
> +#define SPLIT_RADIX_PERMUTATION(num) do { \
> + for(i=0; i<n; i++) {\
> + int k;\
> + j = i;\> + if (s->fft_permutation == FF_FFT_PERM_SWAP_LSBS)\ maybe this if() should be factored out too ? the change looks good though, and iam not sure this is speed relevant enough thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Never trust a computer, one day, it may think you are the virus. -- Compn
signature.asc
Description: PGP signature
_______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
