Another YouTube glitch: 100% of CPU core usage

Vort

Shortly after previous glitch disappeared, another one is activated:
After I visit https://youtube.com/, browser starts consuming 100% of 1 CPU core resources.
It not stops when I close YouTube tab. Only browser restart helps.
Most likely (!) it is again reproduces only when I logged in.
Looks like Google is kidding me
Do anyone knows where problem can be?
It is for sure in browser, but triggered by YouTube.

Pathduck

@Vort Hello, I cannot reproduce this in a clean profile of Vivaldi 3.3. On YT main page Vivaldi uses 0% CPU.

Please follow the steps in the troubleshooting guide:
https://help.vivaldi.com/article/troubleshooting-issues/
It's most likely an extension causing this.

Post a link to a specific video page where it happens if not the main page.
Post the output of the Help > About page in a code block.

Also post a screenshot of the Vivaldi Task Manager (Shift+ESC) showing the CPU usage and what process it's coming from.

Vort

@Pathduck thanks.
Something happened to my Vivaldi profile.
It reminds me of a problem with hangs because of large percent-encoded URLs.
But main YouTube page is a short URL, so more investigation is needed.

With clean profile it is not reproducing.
With non-clean profile it is reproducing even with disabled extensions.

Shift+Esc while glitch is active looks like this:

Vort

@Pathduck I have found approximately where bug is located.
I have cleared view history -> no change.
I have cleared cache -> bug disappeared.

But I have backup of glitchy profile.
Any ideas on how to locate problematic place?

Is there a method to check cache correctness?
Or partially clear it to find problematic record with split-half search or something.

upd. It is not specific to YouTube.
Also reproduces with this URL:
https://developers.google.com/web/tools/chrome-devtools/storage/cache
But not with google.com

upd2. Bug may be related to URLs with ?partial=1 parameters.
Just opening of them causes glitch:
https://developers.google.com/web/tools/chrome-devtools/storage/cache?partial=1&hl=en
https://developers.google.com/speed/public-dns/docs/using?partial=1&hl=en
But not in private window.

upd3. I see some differences when try to load these files with private window and without it:

When glitch happens, "Service Worker" is used. What is that thing? I did not requested it. Will dig deeper.
"The core feature discussed in this tutorial is the ability to intercept and handle network requests, including programmatically managing a cache of responses.", and do it wrong, yeah.

upd4. Bug may be related to service worker, but terminating it do not remove core hang.

upd5. I was slightly wrong, hang uses more than 1 core. 140% consumption is a usual thing.

Pathduck

@Vort So it's the "Browser" process, not the YT tab itself that has the CPU usage.

The service-worker should not cause high CPU, you can view registered ones here and remove them here:
vivaldi://serviceworker-internals

With non-clean profile it is reproducing even with disabled extensions.

Some extensions might hook themselves into the code and would need a browser restart, maybe a proper removal to not take effect.

I see some differences when try to load these files with private window and without it:

Obviously because extensions are still active in the regular window.

I think it's pretty much obvious that it's the proxy extension causing this. Remove it, restart browser and test again.

140% consumption is a usual thing.

Yes, V the task manager shows CPU usage as accumulated across all cores. So for 8 cores, 800% is max.

Vort

@Pathduck said in Another YouTube glitch: 100% of CPU core usage:

So it's the "Browser" process, not the YT tab itself that has the CPU usage.

Yes, service worker triggers problem in browser.

There are more conditions for bug reproducing:

Unregistering of any service worker with serviceworker-internals.
Opening of devtools (so I can't debug it).

Some extensions might hook themselves into the code and would need a browser restart, maybe a proper removal to not take effect.

Removing of all extensions and browser restart do not help.

Obviously because extensions are still active in the regular window.

I think that "logged in" state in google services may be related.

Yes, V the task manager shows CPU usage as accumulated across all cores. So for 8 cores, 800% is max.

I mean it uses 1.4 cores, not 1.0.

Pathduck

@Vort

With clean profile it is not reproducing.

Then it's something in your current profile. And most cases are caused by extensions, or possibly external security software.

I won't recommend a full reset of your profile unless it's absolutely necessary, and you seem like you're capable of troubleshooting so there should be a way to avoid doing that by doing more digging.

You can use Process Explorer to examine threads in a process and see what uses CPU.
https://docs.microsoft.com/en-us/sysinternals/downloads/process-explorer
Choose properties on the Browser PID, go to the Threads tab and sort by CPU.

Vort

@Pathduck said in Another YouTube glitch: 100% of CPU core usage:

You can use Process Explorer to examine threads in a process and see what uses CPU.

Not a single one, lots of them:

Vort

Do debug build exists?
I can try to analyze hang with VTune.
But pure addresses (or asm code of functions) will not help too much.

Vort

At least, I know that 45% of CPU resources are lost inside WaitForSingleObject API function:

(hang starts at ~20 sec)

Pathduck

@Vort Good, at least we know you have the toolset required

For all I know, since I'm unable to reproduce it here on Win 10, it might be your OS causing issues. Maybe someone else with Win7 is able to reproduce it.

Are you able to reproduce the same issue in Vivaldi version 3.2? You can install a standalone downloaded from here: https://vivaldi.com/download/archive/

Of course, it will use a clean profile, so likely not. But then you could install extensions and maybe figure out what causes it. Or you could even copy your 3.3 profile to 3.2 standalone to see if that triggers the issue. There's a lot of things you could do to isolate the problem.

Have you changed any of the flags in vivaldi://flags ?
What is the command line of your Vivaldi, from Help > About?

Vort

@Pathduck said in Another YouTube glitch: 100% of CPU core usage:

For all I know, since I'm unable to reproduce it here on Win 10

You do not have contents of my broken(?) cache.
And I can't send 1.5 GiB of private data to you, of course.

Have you changed any of the flags in vivaldi://flags ?

I don't see easy way to check it.

What is the command line of your Vivaldi, from Help > About?

"D:\Vivaldi\Application\vivaldi.exe" --profile-directory=Default --vivaldi-standalone --flag-switches-begin --flag-switches-end --enable-audio-service-sandbox --ppapi-flash-path="C:\Windows\SysWOW64\Macromed\Flash\pepflashplayer32_32_0_0_156.dll" --save-page-as-mhtml

Are you able to reproduce the same issue in Vivaldi version 3.2? You can install a standalone downloaded from here:

No.
Last version there is Vivaldi.2.10.1745.26.x64.exe (2020-01-10).

So what about debug builds?
It is impossible to get them?

samuvuo

@Vort said in Another YouTube glitch: 100% of CPU core usage:

Have you changed any of the flags in vivaldi://flags ?

I don't see easy way to check it.

Just go to vivaldi://flags and the ones you have changed are listed at the top with a blue dot at the left. The dropdown at right is blue as well.

Vort

@samuvuo said in Another YouTube glitch: 100% of CPU core usage:

Just go to vivaldi://flags and the ones you have changed are listed at the top with a blue dot at the left and right hand side dropdown blue as well.

Thanks. No blue dots.

Vort

I have found something.
Not with procexp, but with procmon.
During hang, this happens:

Pathduck

@Vort said in Another YouTube glitch: 100% of CPU core usage:

You do not have contents of my broken(?) cache.

How are you so sure the issue is with your cache? If you want to test this, close Vivaldi and manually delete the contents of:
Cache, Code Cache, File System, GPUCache, IndexedDB (might reset extension settings), Local Storage, Service Worker, Session Storage.

I know you said the problem goes away if clearing the cache, so I say just delete it and save a lot of investigation. Unless the problem returns, then I still say it's an extension.

Your command line looks clean.

Last version there is Vivaldi.2.10.1745.26.x64.exe (2020-01-10).

No, last version is Vivaldi.3.3.2022.36.x64.exe. Maybe you have an old cache entry of the site, try Ctrl+F5.

During hang, this happens:

And PID 14040 is the main Browser process? It's trying to open files in the File System folder which does not exist.

What kinds of security/privacy/third-party software is your system running?
Is it running CCleaner?
https://valkyrie.comodo.com/kill/chain/c705c0b0210ebda6a3301c6ca9c6091b2ee11d5b/behaviour/summary

Vort

@Pathduck said in Another YouTube glitch: 100% of CPU core usage:

How are you so sure the issue is with your cache? If you want to test this, close Vivaldi and manually delete the contents of:
Cache, Code Cache, File System, GPUCache, IndexedDB (might reset extension settings), Local Storage, Service Worker, Session Storage.

Cache, Code Cache, File System, GPUCache, Local Storage, Session Storage -> no changes
Service Worker -> fixes it until website loads worker again.
IndexedDB -> this is where bug lives.

What kinds of security/privacy/third-party software is your system running?

Kaspersky Free 20.0.14.1085(l).

Is it running CCleaner?

No.

No, last version is Vivaldi.3.3.2022.36.x64.exe. Maybe you have an old cache entry of the site, try Ctrl+F5.

Pathduck

@Vort said in Another YouTube glitch: 100% of CPU core usage:

Service Worker -> fixes it until website loads worker again.

And this is the Youtube SW? The only SW showing in vivaldi://serviceworker-internals ?

Kaspersky Free 20.0.14.1085(l).

Have you tried to exclude the Vivaldi folder from scanning for testing purposes?

https://vivaldi.com/download/archive/

You're getting redirected to the RU version of the page, which apparently is not updated. Go manually to the main URL.

Vort

@Pathduck said in Another YouTube glitch: 100% of CPU core usage:

And this is the Youtube SW?

I have tested with file:
https://developers.google.com/speed/public-dns/docs/using?partial=1&hl=en
And site:
https://developers.google.com/web/tools/chrome-devtools/storage/cache

You're getting redirected to the RU version of the page, which apparently is not updated. Go manually to the main URL.

How?
Removing ru/ and changing it to en/ do not help.
Page is still redirected.

mib2berlin

@Pathduck
@Vort
I get redirected to German version and it does not matter if I C/P or type, it is not updated since a Year.
I don´t need it but may one make a bug report?

Cheers, mib