Performance - high cpu load after a while #567

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1. dobin

   added

   type: bug

   on Jan 20, 2026
2. rabbitstack commented on Jan 20, 2026

   

   rabbitstack

   on Jan 20, 2026

   Last edited by rabbitstack

   Owner

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   Hi @dobin. I appreciate raising the bug. I have a wild guess that excessive CPU utilization could be triggered by a tight loop happening under unpredictable conditions.

   Can I kindly ask for CPU profiles?

   You'll need Go 1.23.x installed on the machine. Then run the following command when Fibratus is stuck in a high CPU consumption state:

   go tool pprof http://localhost:8482/debug/pprof/profile
   

   After the command completes, you'll land into pprof CLI. Then type proto and attach the pb.tgz file.

   Additionally, could you also get the following by opening the URL in the browser?

   • expvars: http://localhost:8482/debug/vars
   • goroutine summary: http://localhost:8482/debug/pprof/goroutine?debug=1

   Lastly, any warning/error logs, or if you notice excessive log messages being written.

   Thanks

   P.S. I'm currently sick, so I'll not be able to look into it immediately.
3. dobin commented on Jan 23, 2026

   

   dobin

   on Jan 23, 2026

   Last edited by dobin

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   profile001.pb.gz
   debug-vars.json
   fibratus.log
   goroutine.txt

   System Boot Time: 20.01.2026, 11:05:52

   
4. rabbitstack commented on Jan 23, 2026

   

   rabbitstack

   on Jan 23, 2026

   Owner

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   Thanks for providing these files. I narrowed it down to an infinite loop which also causes a deadlock. I'll correct this defect in the next version.
5. rabbitstack

   linked a pull request that will close this issuefix: Safe slice mutation during iteration #569on Jan 23, 2026
6. rabbitstack

   closed this as completedin #569on Jan 23, 2026