1333454 - Poor performance of vertical synchronization on http://vsynctester.com/

Status: RESOLVED DUPLICATE of bug 1315230

(Core :: Graphics, defect, P3)

Description

[Michal K]

Attachment: screen.png

User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:51.0) Gecko/20100101 Firefox/51.0

Steps to reproduce:

Visit website http://www.vsynctester.com/ and check the vsync performance for longer period (30 - 60 secs)


Actual results:

Graphics performance is very poor because frame counter is jumping from 30 to 60 fps and vice versa. After a while the vertical synchronization is totally out of. Then it returns to normal state for a while and then the vertical synchronization is again out of. The view of moving image is also stuttering. Probably because of incorrect vertical synchronization.
I made screenshot of visible results.


Expected results:

I would expect similar / nearly performance of Firefox on Linux or macOS, which don't have problem with it.
Very strange thing is, that vertical synchronization and performance were alright  in version 48.0.2 at least.

Comment 2

[jerryj]

http://www.vsynctester.com/firefoxisbroken.html

Comment 3

[Michal K]

(In reply to Mason Chang [:mchang] from comment #1)
> 
> *** This bug has been marked as a duplicate of bug 1315230 ***

Does it mean, that this bug will not be fixed somehow? If yes, then I don't understand why, at least in long term. Because in older versions of Firefox there was no problem with it - at least FF 48.0 was totally alright. From my point of view it is regression and if it was able to be alright before, then it could be alright again too.

Comment 4

[Mason Chang [Inactive] [:mchang]]

(In reply to Michal K from comment #3)
> (In reply to Mason Chang [:mchang] from comment #1)
> > 
> > *** This bug has been marked as a duplicate of bug 1315230 ***
> 
> Does it mean, that this bug will not be fixed somehow? If yes, then I don't
> understand why, at least in long term. Because in older versions of Firefox
> there was no problem with it - at least FF 48.0 was totally alright. From my
> point of view it is regression and if it was able to be alright before, then
> it could be alright again too.

Does it still happen with FF 48 today? You can download an old version here - http://ftp.mozilla.org/pub/firefox/releases/48.0/ or 49 as well. If you want to try a regression tool to find out what happened, you can try this - http://mozilla.github.io/mozregression/quickstart.html

Otherwise, yes, this will probably not be fixed, sorry :(. You can read the discussion from comment 1.

Comment 5

[Michal K]

(In reply to Mason Chang [:mchang] from comment #4)
> (In reply to Michal K from comment #3)
> > (In reply to Mason Chang [:mchang] from comment #1)
> > > 
> > > *** This bug has been marked as a duplicate of bug 1315230 ***
> > 
> > Does it mean, that this bug will not be fixed somehow? If yes, then I don't
> > understand why, at least in long term. Because in older versions of Firefox
> > there was no problem with it - at least FF 48.0 was totally alright. From my
> > point of view it is regression and if it was able to be alright before, then
> > it could be alright again too.
> 
> Does it still happen with FF 48 today? You can download an old version here
> - http://ftp.mozilla.org/pub/firefox/releases/48.0/ or 49 as well. If you
> want to try a regression tool to find out what happened, you can try this -
> http://mozilla.github.io/mozregression/quickstart.html
> 
> Otherwise, yes, this will probably not be fixed, sorry :(. You can read the
> discussion from comment 1.

Hello, 

I tested F48 and F49 and the problem is also there, but rarely and FPS keeps 50 - 60 fps. Also if it happens it returnes back to normal state after a while. 

In F50 it is critical, because it is always out of synchronization. The framerate itself fluctuates from 60 fps to 30 fps and back again. It seems that if out of synchronization gets worse, fps decreases. If out of synchronization gets better, then fps increases back to 60 fps. Always out of synchronization is small or big and it fluctuates.

Michal