Video playback is slowly raising the CPU load and also releases cpu ressources slowly after the video has stopped

[szaimen]

Describe the bug
Video playback is slowly raising the CPU load and also releases cpu ressources slowly after the video has stopped

To Reproduce

0. mount a local external storage to a user
1. upload a mp4 file to nextcloud with around 200MB and 1min length
2. open that file with the viewer app and play it
3. see the cpu load of the server slowly raising; it is doing this until the video has loaded completely in the background and the viewer window was closed. (it seems to load the complete video in the background also if the window was already closed).

Also it releases cpu processes very slowly after the video was closed - it needs around 2min to come back to normal load.

Expected behavior
the video playback with the viewer shouldn't considerably effect the cpu load of the server.

Screenshots

Desktop (please complete the following information):

• OS: Win10
• Browser chromium based browser
• Version 81

Additional context
That problem doesn't appear when not using external storage. it is then only at around 2.0 max which is okay.

BTW: I have tried to disable the viewer and play it with the files_videoplayer and the cpu load much lower and not raising.

addditional info: With the viewer the php-fpm count seems to slowly raise.

Server:
ubuntu 18.04
php 7.2
nextcloud 18.0.4

[skjnldsv]

Hey! :)
I guess we would need an extensive debugging of the php process behind it. I'm unfortunately not the expert for this. I guess this is exactly the same as downloading any big file from nextcloud. I think I saw an issue passing by for this.

Do you have the knowledge for it?

[szaimen]

Hi!

I have unfortunately no experience in debugging php processes.

Is there a good explanation how to do that available so that I can try that out or is there somebody who has the experience to do that and can give me an explanation how to do that or do it himself?

I mean mounting a local external storage folder and uploading a well sized mp4 video to it isn't that complicated, I would say.

[szaimen]

I found out that this happens due to a cifs mount.
I could speed up the loading by a lot through a small change.
So this can be closed, imo.