[FFmpeg-devel] [PATCH v2] avfilter/pthread: rewrite implementation

[Michael Niedermayer]

On Mon, Jul 10, 2017 at 10:53:42AM +0200, wm4 wrote:
> On Sat, 8 Jul 2017 01:45:06 +0200
> Michael Niedermayer <michael at niedermayer.cc> wrote:
> 
> > On Fri, Jul 07, 2017 at 09:04:37PM +0700, Muhammad Faiz wrote:
> > > Avoid pthread_cond_broadcast that wakes up all workers. Make each of them
> > > uses distict mutex/cond. Also let main thread help running jobs.
> > > 
> > > Benchmark using afir with threads=5 and 4096 taps fir:
> > > channels=1:
> > > old:
> > >     1849650 decicycles in afir_execute,       2 runs,      0 skips
> > >     1525719 decicycles in afir_execute,    1024 runs,      0 skips
> > >     1546032 decicycles in afir_execute,   16356 runs,     28 skips
> > > new:
> > >     1495525 decicycles in afir_execute,       2 runs,      0 skips
> > >      968897 decicycles in afir_execute,    1024 runs,      0 skips
> > >      941286 decicycles in afir_execute,   16384 runs,      0 skips
> > > 
> > > channels=2:
> > > old:
> > >     3135485 decicycles in afir_execute,       2 runs,      0 skips
> > >     1967158 decicycles in afir_execute,    1024 runs,      0 skips
> > >     1802430 decicycles in afir_execute,   16364 runs,     20 skips
> > > new:
> > >     1864750 decicycles in afir_execute,       2 runs,      0 skips
> > >     1437792 decicycles in afir_execute,    1024 runs,      0 skips
> > >     1183963 decicycles in afir_execute,   16382 runs,      2 skips
> > > 
> > > channels=4:
> > > old:
> > >     4879925 decicycles in afir_execute,       2 runs,      0 skips
> > >     3557950 decicycles in afir_execute,    1022 runs,      2 skips
> > >     3206843 decicycles in afir_execute,   16379 runs,      5 skips
> > > new:
> > >     2962320 decicycles in afir_execute,       2 runs,      0 skips
> > >     2450430 decicycles in afir_execute,    1024 runs,      0 skips
> > >     2446219 decicycles in afir_execute,   16383 runs,      1 skips
> > > 
> > > channels=8:
> > > old:
> > >     6032455 decicycles in afir_execute,       2 runs,      0 skips
> > >     4838614 decicycles in afir_execute,    1023 runs,      1 skips
> > >     4720760 decicycles in afir_execute,   16369 runs,     15 skips
> > > new:
> > >     5228150 decicycles in afir_execute,       2 runs,      0 skips
> > >     4592129 decicycles in afir_execute,    1023 runs,      1 skips
> > >     4469067 decicycles in afir_execute,   16383 runs,      1 skips  
> > 
> > this causes a strange change:
> > 
> > ./ffmpeg -i ~/videos/matrixbench_mpeg2.mpg  -vcodec libxavs  -vf scale=80x60 -t 1 file3.nut
> > 
> > results in different files before and after this patch. Neither plays
> > i suspect this is not a bug in the patch but something odd elsewhere
> > but i dont know
> 

> OK so you're saying there's no bug.

no, i didnt say that


> Something changed,

yes


> and you're too
> lazy to investigate,

no, i didnt say that either, nor is that true


> but I guess he has all time in the world.
> 
> So why should he care?

You seem to try to imply that i asked Muhammad to look into this
or take care of or fix the issue.

please read my reply again its just 3 lines, i have not asked
Muhammad to do anything. Nor was it intended to imply that.
It is just a report of some odd findings which were triggered by
the patch but which quite possibly are unrelated to the patch excpt
by coincidence.

Thanks

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

Breaking DRM is a little like attempting to break through a door even
though the window is wide open and the only thing in the house is a bunch
of things you dont want and which you would get tomorrow for free anyway
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