[FFmpeg-trac] #5568(swscale:open): POWER8 VSX vectorization libswscale/swscale.c

FFmpeg trac at avcodec.org
Tue Jun 19 23:23:46 EEST 2018

#5568: POWER8 VSX vectorization libswscale/swscale.c
             Reporter:  edelsohn     |                    Owner:
                 Type:  enhancement  |                   Status:  open
             Priority:  wish         |                Component:  swscale
              Version:  git-master   |               Resolution:
             Keywords:  bounty vsx   |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |

Comment (by cehoyos):

 Replying to [comment:11 bookmoons]:
 > Hi guys. I have something toward a vectorized hScale8To15_c from
 swscale.c. Profiling with callgrind

 (You are expected to test with FFmpeg's TIMER macros unless this does not
 work for some reason.)

 > shows it's a little faster than the unoptimized version, but not as fast
 as the extant altivec version. Hope to figure out what's causing the
 difference and improve it.
 > Unoptimized - 11,140,574
 > VSX optimized - 9,670,008
 > Altivec optimized - 3,511,966
 > Does this seem like the right direction?
 The direction may be all right but to be accepted in the codebase the
 speed has to be improved significantly.
 If you are interested in the bounty, make sure to first optimize one
 function to learn about our requirements: A patch that unfortunately
 contained a lot of work was rejected because it only offered minimal speed

Ticket URL: <https://trac.ffmpeg.org/ticket/5568#comment:12>
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