On Sun, 18 Oct 2015 11:06:57 -0400 Ganesh Ajjanagadde <gajja...@mit.edu> wrote:
> On Sun, Oct 18, 2015 at 11:01 AM, wm4 <nfx...@googlemail.com> wrote: > > On Sun, 18 Oct 2015 10:47:52 -0400 > > Ganesh Ajjanagadde <gajjanaga...@gmail.com> wrote: > > > >> Commit e11e32686fdb21aded1ccf70202f1fffe87bb6a2 explains why replacing > >> qsort with AV_QSORT yields performance improvements. > >> > >> This replaces all existing uses of libc's qsort with AV_QSORT. > >> > >> Benchmarks deemed unnecessary due to existing claims about AV_QSORT. > >> Tested with FATE. > >> > >> Signed-off-by: Ganesh Ajjanagadde <gajjanaga...@gmail.com> > >> --- > >> cmdutils.c | 3 ++- > >> cmdutils_opencl.c | 3 ++- > >> ffmpeg.c | 3 ++- > >> libavcodec/aacsbr_template.c | 14 ++++++++------ > >> libavcodec/huffman.c | 3 ++- > >> libavcodec/motion_est_template.c | 3 ++- > >> libavcodec/utvideodec.c | 4 ++-- > >> libavcodec/utvideoenc.c | 5 +++-- > >> libavfilter/f_sendcmd.c | 3 ++- > >> libavfilter/vf_deshake.c | 3 ++- > >> libavfilter/vf_palettegen.c | 2 +- > >> libavfilter/vf_paletteuse.c | 2 +- > >> libavfilter/vf_removegrain.c | 7 ++++--- > >> libavformat/subtitles.c | 10 +++++++--- > >> libswresample/swresample-test.c | 3 ++- > >> tests/checkasm/checkasm.c | 4 ++-- > >> 16 files changed, 44 insertions(+), 28 deletions(-) > > > > By how much does this increase binary code size? > > > > Is it really faster? (libc qsort() could use a better algorithm, > > even if it has to go through indirections.) > > Michael has already shown that AV_QSORT is faster. libc's qsort can > easily be looked up: Michael already uses most of the tricks (usage of > stack to avoid recursion, etc). The main benefits come from the > inlining. Where? It might depend on the actual data to be sorted. Is the data completely random? Is it already sorted in most cases? etc. I'm not fond of such frivolous mass-changes. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
