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I'm seeing high CPU usage on YouTube after recent updates on Xubuntu. I think it started when they enabled GPU acceleration by default. Previously I could watc

I'm seeing high CPU usage on YouTube after recent updates on Xubuntu. I think it started when they enabled GPU acceleration by default. Previously I could watch even FHD videos without much fan noise, but after recent updates, fans spin at the max speed by playing even 480p quality vids. Anyone else?

jansan 6y ago
GPU acceleration is not a magic bullet it seems. In our case drawing large SVGs suddenly becomes really slow when GPU rasterization is enabled. Chrome has the same problem. I really hope we will see more polishing in this area and maybe a cooperation between Chrome and Firefox developers?
- ducktective 6y ago
  Thing is, when I play the same video with VLC which uses HW decoding, it doesn't even break a sweat. So I think there might be something wrong on the browser part...
  - jansan 6y ago
    You can issue a bug report on https://bugzilla.mozilla.org/home https://bugzilla.mozilla.org/home Sometimes bugs are fixed really fast, sometimes never. Just give it a try.
  - danielEM 6y ago
    There could be something related to FAN thresholds that resides in BIOS directly thus starting using GPU just slightly over some minimal limit might raise FAN speeds significantly and not be related to temperature raise as there is some inertia between temperature readings and real temperature inside GPU core. I'm also experiencing FAN noise raise on my Ryzen APU based laptop.
  - samoa42 6y ago
    i mostly stopped bothering with in-browser video when mpv wiht youtube-dl integration came around. either drag the url to the player window or use an open-with addon. hardware decoding, no ads, buffering as i please
- muizelaar 6y ago
  Do you have an example url for this?
  - jansan 6y ago
    Here is a bug report that shows the issue on Chrome. It is roughly 7 times slower with hardware rasterization enabled: https://bugs.chromium.org/p/chromium/issues/detail?id=1143672#makechanges https://bugs.chromium.org/p/chromium/issues/detail?id=114367... This particular example is only slow on Chrome. Even if you move the edge of the shape into the viewport Firefox is much faster than Chrome. But I know from real life examples that Firefox becomes slow if handling large SVGs. I will have to investigate this and file a bug report.
    - jansan 6y ago
      I checked again with our app on Firefox and performance is not that bad. Rendering gets a slower with large SVGs, but it is still good and there is not much difference between hardware rendering enabled and disabled. So I was either wrong about slow performance on Firefox or things have improved recently.
padenot 6y ago
Would you mind capturing a profile? https://blog.paul.cx/post/profiling-firefox-media-workloads/#the-media-preset https://blog.paul.cx/post/profiling-firefox-media-workloads/... explains how. It's very very very simple and quick, there is a video demo and a text explaining what to do, and then you can open a bug at https://bugzilla.mozilla.org/enter_bug.cgi?product=Core&component=Audio%2FVideo%3A%20playback https://bugzilla.mozilla.org/enter_bug.cgi?product=Core&comp..., with the profile link (you can login with a github account or email). This will be triaged and hopefully we'll understand what's up. Please use a Nightly build or a Mozilla-provided build when doing so (so there are symbols). It's just a matter of downloading and untaring the tarball. Please also attach a copy of `about:support` raw data (button at the top), so we can understand what your configuration is: desktop Linux systems can be pretty diverse and sometimes it isn't clear what works, what doesn't and why. If you're playing 480p, then youtube might be serving you AV1, and this is (for now) using the CPU (trading a lot less bandwidth for increased CPU usage), you can check the codec it's using by right clicking on the video and clicking on `Stats for nerds`, there is the codec string. You can adjust your codec preferences in your youtube profile I believe.
- danielEM 6y ago
  Just did some tests on Firefox 83 and DOM reflow time grows exponentially with the depth of DOM tree. With grid elements of depth 10 single reflow takes seconds on my Ryzen laptop while on chromium is not noticable at all.
  - muizelaar 6y ago
    Can you post a link to a test case?
    - danielEM 6y ago
      Did already profiling and posted a bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1682686 https://bugzilla.mozilla.org/show_bug.cgi?id=1682686 https://jsfiddle.net/fuh7c894/ https://jsfiddle.net/fuh7c894/
penguin_booze 6y ago
I'm on Linux. I stubled on webrender from a blog yesterday, and enabled it. My observation was the same - high CPU usage, so I then disabled. Got 84.0 today, and gave it another go. It appears to be behaving well so far. So I'm guessing there was some fix in 84.0 that made it work for me.
deleted 6y ago
[deleted]

jansan 6y ago

GPU acceleration is not a magic bullet it seems. In our case drawing large SVGs suddenly becomes really slow when GPU rasterization is enabled. Chrome has the same problem. I really hope we will see more polishing in this area and maybe a cooperation between Chrome and Firefox developers?

ducktective 6y ago
Thing is, when I play the same video with VLC which uses HW decoding, it doesn't even break a sweat. So I think there might be something wrong on the browser part...
- jansan 6y ago
  You can issue a bug report on https://bugzilla.mozilla.org/home https://bugzilla.mozilla.org/home Sometimes bugs are fixed really fast, sometimes never. Just give it a try.
- danielEM 6y ago
  There could be something related to FAN thresholds that resides in BIOS directly thus starting using GPU just slightly over some minimal limit might raise FAN speeds significantly and not be related to temperature raise as there is some inertia between temperature readings and real temperature inside GPU core. I'm also experiencing FAN noise raise on my Ryzen APU based laptop.
- samoa42 6y ago
  i mostly stopped bothering with in-browser video when mpv wiht youtube-dl integration came around. either drag the url to the player window or use an open-with addon. hardware decoding, no ads, buffering as i please
muizelaar 6y ago
Do you have an example url for this?
- jansan 6y ago
  Here is a bug report that shows the issue on Chrome. It is roughly 7 times slower with hardware rasterization enabled: https://bugs.chromium.org/p/chromium/issues/detail?id=1143672#makechanges https://bugs.chromium.org/p/chromium/issues/detail?id=114367... This particular example is only slow on Chrome. Even if you move the edge of the shape into the viewport Firefox is much faster than Chrome. But I know from real life examples that Firefox becomes slow if handling large SVGs. I will have to investigate this and file a bug report.
  - jansan 6y ago
    I checked again with our app on Firefox and performance is not that bad. Rendering gets a slower with large SVGs, but it is still good and there is not much difference between hardware rendering enabled and disabled. So I was either wrong about slow performance on Firefox or things have improved recently.

padenot 6y ago

Would you mind capturing a profile? https://blog.paul.cx/post/profiling-firefox-media-workloads/#the-media-preset https://blog.paul.cx/post/profiling-firefox-media-workloads/... explains how. It's very very very simple and quick, there is a video demo and a text explaining what to do, and then you can open a bug at https://bugzilla.mozilla.org/enter_bug.cgi?product=Core&component=Audio%2FVideo%3A%20playback https://bugzilla.mozilla.org/enter_bug.cgi?product=Core&comp..., with the profile link (you can login with a github account or email). This will be triaged and hopefully we'll understand what's up. Please use a Nightly build or a Mozilla-provided build when doing so (so there are symbols). It's just a matter of downloading and untaring the tarball. Please also attach a copy of `about:support` raw data (button at the top), so we can understand what your configuration is: desktop Linux systems can be pretty diverse and sometimes it isn't clear what works, what doesn't and why. If you're playing 480p, then youtube might be serving you AV1, and this is (for now) using the CPU (trading a lot less bandwidth for increased CPU usage), you can check the codec it's using by right clicking on the video and clicking on `Stats for nerds`, there is the codec string. You can adjust your codec preferences in your youtube profile I believe.

danielEM 6y ago
Just did some tests on Firefox 83 and DOM reflow time grows exponentially with the depth of DOM tree. With grid elements of depth 10 single reflow takes seconds on my Ryzen laptop while on chromium is not noticable at all.
- muizelaar 6y ago
  Can you post a link to a test case?
  - danielEM 6y ago
    Did already profiling and posted a bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1682686 https://bugzilla.mozilla.org/show_bug.cgi?id=1682686 https://jsfiddle.net/fuh7c894/ https://jsfiddle.net/fuh7c894/

penguin_booze 6y ago

I'm on Linux. I stubled on webrender from a blog yesterday, and enabled it. My observation was the same - high CPU usage, so I then disabled. Got 84.0 today, and gave it another go. It appears to be behaving well so far. So I'm guessing there was some fix in 84.0 that made it work for me.

deleted 6y ago

[deleted]