On 5 July 2017 at 16:22, wm4 <nfx...@googlemail.com> wrote:
> On Wed, 5 Jul 2017 16:12:07 +0100
> Rostislav Pehlivanov <atomnu...@gmail.com> wrote:
>
> > On 5 July 2017 at 07:15, Muhammad Faiz <mfc...@gmail.com> wrote:
> >
> > > Make it thread-safe and avoid redundant initialization.
> > >
> > > Signed-off-by: Muhammad Faiz <mfc...@gmail.com>
> > > ---
> > > libavcodec/fft_template.c | 81 ++++++++++++++++++++++++++++++
> > > +++++++++++------
> > > 1 file changed, 71 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/libavcodec/fft_template.c b/libavcodec/fft_template.c
> > > index 6477372..6c77854 100644
> > > --- a/libavcodec/fft_template.c
> > > +++ b/libavcodec/fft_template.c
> > > @@ -29,11 +29,19 @@
> > > #include <stdlib.h>
> > > #include <string.h>
> > > #include "libavutil/mathematics.h"
> > > +#include "libavutil/thread.h"
> > > #include "fft.h"
> > > #include "fft-internal.h"
> > >
> > > #if FFT_FIXED_32
> > > #include "fft_table.h"
> > > +
> > > +static void av_cold fft_lut_init(void)
> > > +{
> > > + int n = 0;
> > > + ff_fft_lut_init(ff_fft_offsets_lut, 0, 1 << 17, &n);
> > > +}
> > > +
> > > #else /* FFT_FIXED_32 */
> > >
> > > /* cos(2*pi*x/n) for 0<=x<=n/4, followed by its reverse */
> > > @@ -52,6 +60,66 @@ COSTABLE(16384);
> > > COSTABLE(32768);
> > > COSTABLE(65536);
> > > COSTABLE(131072);
> > > +
> > > +static av_cold void init_ff_cos_tabs(int index)
> > > +{
> > > + int i;
> > > + int m = 1<<index;
> > > + double freq = 2*M_PI/m;
> > > + FFTSample *tab = FFT_NAME(ff_cos_tabs)[index];
> > > + for(i=0; i<=m/4; i++)
> > > + tab[i] = FIX15(cos(i*freq));
> > > + for(i=1; i<m/4; i++)
> > > + tab[m/2-i] = tab[i];
> > > +}
> > > +
> > > +typedef struct CosTabsInitOnce {
> > > + void (*func)(void);
> > > + AVOnce control;
> > > +} CosTabsInitOnce;
> > > +
> > > +#define INIT_FF_COS_TABS_FUNC(index, size) \
> > > +static av_cold void init_ff_cos_tabs_ ## size (void)\
> > > +{ \
> > > + init_ff_cos_tabs(index); \
> > > +}
> > > +
> > > +INIT_FF_COS_TABS_FUNC(4, 16)
> > > +INIT_FF_COS_TABS_FUNC(5, 32)
> > > +INIT_FF_COS_TABS_FUNC(6, 64)
> > > +INIT_FF_COS_TABS_FUNC(7, 128)
> > > +INIT_FF_COS_TABS_FUNC(8, 256)
> > > +INIT_FF_COS_TABS_FUNC(9, 512)
> > > +INIT_FF_COS_TABS_FUNC(10, 1024)
> > > +INIT_FF_COS_TABS_FUNC(11, 2048)
> > > +INIT_FF_COS_TABS_FUNC(12, 4096)
> > > +INIT_FF_COS_TABS_FUNC(13, 8192)
> > > +INIT_FF_COS_TABS_FUNC(14, 16384)
> > > +INIT_FF_COS_TABS_FUNC(15, 32768)
> > > +INIT_FF_COS_TABS_FUNC(16, 65536)
> > > +INIT_FF_COS_TABS_FUNC(17, 131072)
> > > +
> > > +static CosTabsInitOnce cos_tabs_init_once[] = {
> > > + { NULL },
> > > + { NULL },
> > > + { NULL },
> > > + { NULL },
> > > + { init_ff_cos_tabs_16, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_32, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_64, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_128, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_256, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_512, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_1024, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_2048, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_4096, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_8192, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_16384, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_32768, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_65536, AV_ONCE_INIT },
> > > + { init_ff_cos_tabs_131072, AV_ONCE_INIT },
> > > +};
> > > +
> > > #endif
> > > COSTABLE_CONST FFTSample * const FFT_NAME(ff_cos_tabs)[] = {
> > > NULL, NULL, NULL, NULL,
> > > @@ -90,14 +158,7 @@ static int split_radix_permutation(int i, int n,
> int
> > > inverse)
> > > av_cold void ff_init_ff_cos_tabs(int index)
> > > {
> > > #if (!CONFIG_HARDCODED_TABLES) && (!FFT_FIXED_32)
> > > - int i;
> > > - int m = 1<<index;
> > > - double freq = 2*M_PI/m;
> > > - FFTSample *tab = FFT_NAME(ff_cos_tabs)[index];
> > > - for(i=0; i<=m/4; i++)
> > > - tab[i] = FIX15(cos(i*freq));
> > > - for(i=1; i<m/4; i++)
> > > - tab[m/2-i] = tab[i];
> > > + ff_thread_once(&cos_tabs_init_once[index].control,
> > > cos_tabs_init_once[index].func);
> > > #endif
> > > }
> > >
> > > @@ -176,8 +237,8 @@ av_cold int ff_fft_init(FFTContext *s, int nbits,
> int
> > > inverse)
> > >
> > > #if FFT_FIXED_32
> > > {
> > > - int n=0;
> > > - ff_fft_lut_init(ff_fft_offsets_lut, 0, 1 << 17, &n);
> > > + static AVOnce control = AV_ONCE_INIT;
> > >
> >
> > This needs to be a global variable.
>
> It's not global, but it's static, so good enough for the purpose?
>
> I'm not sure how the file being a template factors into this, though.
>
> (Patch LGTM btw.)
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
Ah, yeah, its fine then. Patch LGTM as well.
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
