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Firefox sometimes consumes extra CPU at startup for several minutes

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Silntknight
Silntknight
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Occasionally, and typically only after a reboot, Firefox starts consuming a significant amount of CPU time. This typically goes on for several minutes, and if I close and reopen Firefox, the process begins again. It's enough CPU that the fans kick on high through most of the process, and considering I'm only opening the browser (not even switching tabs to actively load any other pages), I don't know why it would do this. Similarly, if it were related to typical startup behavior, why doesn't it do this every time?

While I generally trust that this is intentional and is unlikely the result of malware, I'd still like to know why Firefox does this at all and what it's doing. I'm not sure if I can collect any logs or get any other info about this. From process monitors, it appears to be the main executable that's consuming the additional CPU and not any of the isolated instances.

I collected the troubleshooting information, and saved it, but I am hesitant to share without knowing what type of information is contained (and I can see some sensitive stuff like file paths)

OS: Ubuntu 24.04 LTS (Linux 6.8.0-36-generic) Firefox Version: 127.0.2 (deb) Build ID: 20240624183754

Occasionally, and typically only after a reboot, Firefox starts consuming a significant amount of CPU time. This typically goes on for several minutes, and if I close and reopen Firefox, the process begins again. It's enough CPU that the fans kick on high through most of the process, and considering I'm only opening the browser (not even switching tabs to actively load any other pages), I don't know why it would do this. Similarly, if it were related to typical startup behavior, why doesn't it do this every time? While I generally trust that this is intentional and is unlikely the result of malware, I'd still like to know why Firefox does this at all and what it's doing. I'm not sure if I can collect any logs or get any other info about this. From process monitors, it appears to be the main executable that's consuming the additional CPU and not any of the isolated instances. I collected the troubleshooting information, and saved it, but I am hesitant to share without knowing what type of information is contained (and I can see some sensitive stuff like file paths) OS: Ubuntu 24.04 LTS (Linux 6.8.0-36-generic) Firefox Version: 127.0.2 (deb) Build ID: 20240624183754

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