[FFmpeg-devel] [PATCH v5] libswscale/ppc: VSX-optimize 9-16 bit yuv2planeX

[Lauri Kasanen]

On Sat, 12 Jan 2019 14:52:07 +0100
Michael Niedermayer <michael at niedermayer.cc> wrote:

> On Sat, Jan 12, 2019 at 10:47:50AM +0200, Lauri Kasanen wrote:
> > ./ffmpeg_g -f rawvideo -pix_fmt rgb24 -s hd1080 -i /dev/zero -pix_fmt yuv420p16be \
> > -s 1920x1728 -f null -vframes 100 -v error -nostats -
> > 
> > 9-14 bit funcs get about 6x speedup, 16-bit gets about 15x.
> > Fate passes, each format tested with an image to video conversion.
> > 
> > Only POWER8 includes 32-bit vector multiplies, so POWER7 is locked out
> > of the 16-bit function. This includes the vec_mulo/mule functions too,
> > not just vmuluwm.
> > 
> > yuv420p9le
> >   12341 UNITS in planarX,  130976 runs,     96 skips
> >   73752 UNITS in planarX,  131066 runs,      6 skips
> > yuv420p9be
> >   12364 UNITS in planarX,  131025 runs,     47 skips
> >   73001 UNITS in planarX,  131055 runs,     17 skips
> > yuv420p10le
> >   12386 UNITS in planarX,  131042 runs,     30 skips
> >   72735 UNITS in planarX,  131062 runs,     10 skips
> > yuv420p10be
> >   12337 UNITS in planarX,  131045 runs,     27 skips
> >   72734 UNITS in planarX,  131057 runs,     15 skips
> > yuv420p12le
> >   12236 UNITS in planarX,  131058 runs,     14 skips
> >   73029 UNITS in planarX,  131062 runs,     10 skips
> > yuv420p12be
> >   12218 UNITS in planarX,  130973 runs,     99 skips
> >   72402 UNITS in planarX,  131069 runs,      3 skips
> > yuv420p14le
> >   12168 UNITS in planarX,  131067 runs,      5 skips
> >   72480 UNITS in planarX,  131069 runs,      3 skips
> > yuv420p14be
> >   12358 UNITS in planarX,  130948 runs,    124 skips
> >   73772 UNITS in planarX,  131063 runs,      9 skips
> > yuv420p16le
> >   10439 UNITS in planarX,  130911 runs,    161 skips
> >  157923 UNITS in planarX,  131068 runs,      4 skips
> > yuv420p16be
> >   10463 UNITS in planarX,  130874 runs,    198 skips
> >  154405 UNITS in planarX,  131061 runs,     11 skips
> 
> The number of skips in the benchmark is much larger on one
> side. That way the numbers become hard to compare as
> more cases aer skipped on one side
> 
> please adjust the parameters so the skip counts are compareable
> or redo the tests until the numbers are more similar
> thanks

How do I do that? It's a VM, so there are going to be pauses no matter
what, when other VMs run. Or should I take the largest run count with
about the same skips?

- Lauri