Public bug reported:

At a high level, in certain instances we’re experiencing sustained
abnormally high (100%) CPU utilization from Firefox.  This utilization
is competing with other critical application processes on the systems,
starving them of resources, causing issues in the application
processing.  This happens, at times, when the browser should be idle,
even.

We have not isolated this issue to be a bug with firefox itself or an issue 
with the webpage content being provided to the browser. Regardless, here are 
the symptoms:
    * CPU usage is extremely high for the FireFox process (>100% on average vs 
<10% average for healthy stations) even while the screen is sitting idle (no 
animations, user interactions, etc.)
   * We have isolated the thread within FireFox causing the most CPU usage to 
the Renderer thread with the SwComposite threads also consuming abnormally high 
CPU.
   * In the FireFox Task and Process Managers, we have validated there is no 
single tab or window consuming abnormally high CPU, just the FireFox master 
process.
   * Additionally, we have confirmed that the FireFox browser history (taken 
from the places.sqlite file) does not have any webpages being loaded during the 
times when CPU consumption experiences a step function change up or down.
   * We also have linux perf logs for the FireFox process on healthy stations 
and impacted stations while sitting idle on the login screen, which can provide 
some stack traces for the Renderer and other threads which may be more useful 
to someone with FireFox expertise.
   * The biggest difference is that the impacted workcells have the Renderer 
and Compositor 'tracks' very active while the healthy workcells see no usage of 
these tracks at all.
   * These 2 tracks also have supporting tracks such as SwComposite and 
WRRendererBackend#X. There were 2 of each of these, which may indicate the 
issue is happening across both FireFox windows. For reference, the stations 
always have 2 windows open: one for the screen UI and one for the projector on 
the pod face.
   * (Using the term 'track' here as defined by the open source FireFox 
profiler: https://profiler.firefox.com/. Basically a thread within the FireFox 
main process) 
   * There are many memory copy and SW interrupt calls being made in these 
tracks.
   * This validates that FireFox is contributing to increased software 
interrupt load
   * Additionally, we found an interesting pair of calls occurring periodically 
in the Renderer track. We have not deep dived these yet, but on the off chance 
it matters, we're including it in this report:
   * viaduct_log_error - every 50 - 500ms
   * wgpu_render_pass_end_pipeline_statistics_query - every 50 - 1000ms

** Affects: firefox (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/2048792

Title:
  Firefox utilizins 100% of station CPU

Status in firefox package in Ubuntu:
  New

Bug description:
  At a high level, in certain instances we’re experiencing sustained
  abnormally high (100%) CPU utilization from Firefox.  This utilization
  is competing with other critical application processes on the systems,
  starving them of resources, causing issues in the application
  processing.  This happens, at times, when the browser should be idle,
  even.

  We have not isolated this issue to be a bug with firefox itself or an issue 
with the webpage content being provided to the browser. Regardless, here are 
the symptoms:
      * CPU usage is extremely high for the FireFox process (>100% on average 
vs <10% average for healthy stations) even while the screen is sitting idle (no 
animations, user interactions, etc.)
     * We have isolated the thread within FireFox causing the most CPU usage to 
the Renderer thread with the SwComposite threads also consuming abnormally high 
CPU.
     * In the FireFox Task and Process Managers, we have validated there is no 
single tab or window consuming abnormally high CPU, just the FireFox master 
process.
     * Additionally, we have confirmed that the FireFox browser history (taken 
from the places.sqlite file) does not have any webpages being loaded during the 
times when CPU consumption experiences a step function change up or down.
     * We also have linux perf logs for the FireFox process on healthy stations 
and impacted stations while sitting idle on the login screen, which can provide 
some stack traces for the Renderer and other threads which may be more useful 
to someone with FireFox expertise.
     * The biggest difference is that the impacted workcells have the Renderer 
and Compositor 'tracks' very active while the healthy workcells see no usage of 
these tracks at all.
     * These 2 tracks also have supporting tracks such as SwComposite and 
WRRendererBackend#X. There were 2 of each of these, which may indicate the 
issue is happening across both FireFox windows. For reference, the stations 
always have 2 windows open: one for the screen UI and one for the projector on 
the pod face.
     * (Using the term 'track' here as defined by the open source FireFox 
profiler: https://profiler.firefox.com/. Basically a thread within the FireFox 
main process) 
     * There are many memory copy and SW interrupt calls being made in these 
tracks.
     * This validates that FireFox is contributing to increased software 
interrupt load
     * Additionally, we found an interesting pair of calls occurring 
periodically in the Renderer track. We have not deep dived these yet, but on 
the off chance it matters, we're including it in this report:
     * viaduct_log_error - every 50 - 500ms
     * wgpu_render_pass_end_pipeline_statistics_query - every 50 - 1000ms

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