[vlc-devel] [PATCH] Drop POSIX real-time priorities

[Steve Lhomme]

On 2020-03-31 16:07, Rémi Denis-Courmont wrote:
> Le tiistaina 31. maaliskuuta 2020, 9.44.49 EEST Steve Lhomme a écrit :
>> On 2020-03-30 16:50, Rémi Denis-Courmont wrote:
>>> Le maanantaina 30. maaliskuuta 2020, 16.48.23 EEST Francois Cartegnie a
>>> écrit>
>>>> Le 30/03/2020 à 15:44, Rémi Denis-Courmont a écrit :
>>>>> This only worked with root privileges, meaning it was pure placebo for
>>>>> those few users that actually invoked the command line flag.
>>>>>
>>>>> And then it seems more likely to crash the system than the achieve its
>>>>> purpose, seen as VLC was never designed to handle real-time scheduling.
>>>>
>>>> AFAIU the vlc_thread priorities have also zero effect.
>>>
>>> Sure, I am in favor of removing vlc_set_priority() and the priority
>>> argument to vlc_clone(). But maybe some other platforms want to keep
>>> their placebo.
>> How is that a placebo ? It does have an effect on Windows
> 
> The OS scheduler takes care of that sort of thing better than code written by
> VLC devs two decades ago. That's how.

The fact is may not be well written doesn't mean it doesn't have its 
use. Prioritizing audio over video/ui/network in a multimedia player is 
certainly desirable.

And I don't think the priorities currently applied have zero effect. 
They are not placebos.

I also fail to see how the OS can tell which thread should be schedule 
first/more often.