[FFmpeg-devel] [PATCH] lavc/aacenc_utils: unroll abs_pow34_v loop

Michael Niedermayer michael at niedermayer.cc
Wed Mar 23 00:42:14 CET 2016


On Tue, Mar 22, 2016 at 11:37:16AM -0700, Ganesh Ajjanagadde wrote:
> On Tue, Mar 22, 2016 at 11:30 AM, Rostislav Pehlivanov
> <atomnuker at gmail.com> wrote:
> > On 22 March 2016 at 18:14, Ganesh Ajjanagadde <gajjanag at gmail.com> wrote:
> >>
> >>
> >> Per doc/optimization.txt, aac is a widely used codec, so even a 0.1%
> >> improvement in aac is fair game for optimizations, assuming it is a
> >> small code change. Of course, one can debate whether this is small or
> >> not. I view it as simple and clean, others may disagree.
> >
> >
> > Nope, I still doubt that that 0.1% is a definite performance improvement.
> 
> Then change doc/optimization.txt.
> 
> > Sure it might be on your machine but who knows, maybe for someone else
> > it'll be a 0.1% decrease in performance or hell, a 1% decrease.
> 
> Don't speculate, show evidence. This is something that can be said
> about essentially all patches that affect performance. For example,
> who knows, a compiler may actually omit worse code on a certain
> architecture for something that should be an improvement. This just
> highlights the ridiculousness of this line of reasoning.

if no consense can be found on this ...
maybe theres an easy way out of this problem ?
git makes it easy for 2 people to keep some differences

If one doubts changes improve speed and another belives they do
the 2 can just keep their git trees different.
And once there are 50 disputed 0.1% improvments one git tree will
either be 5% faster or not.
would anyone object to applying 50 small changes which together make
the code 5% faster ?

of course if people agree on changes in the first place that would
be even better

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many things microsoft did are stupid, but not doing something just because
microsoft did it is even more stupid. If everything ms did were stupid they
would be bankrupt already.
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