[tor-bugs] #25461 [Core Tor/Tor]: main event-loop spins consuming 100% of a CPU core at times

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#25461: main event-loop spins consuming 100% of a CPU core at times
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 Reporter:  Dhalgren                  |          Owner:  (none)
     Type:  defect                    |         Status:  new
 Priority:  Medium                    |      Milestone:  Tor: 0.3.3.x-final
Component:  Core Tor/Tor              |        Version:  Tor: 0.3.3.3-alpha
 Severity:  Normal                    |     Resolution:
 Keywords:  regression?, performance  |  Actual Points:
Parent ID:                            |         Points:
 Reviewer:                            |        Sponsor:
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Comment (by Dhalgren):

 attached rest of the slice histograms

 times in seconds for each are

 00 5.697
 01 5.615
 02 5.625
 03 5.556
 04 5.567
 05 5.574
 06 7.137
 07 3.666

 can provide grep extracts or entire log

 recalling I saw this on 0.2.9.14 so probably not a (recent) regression or
 KIST

 guess is event loop is not blocking rather than some function hogging CPU,
 but just a guess; performance browsing through exit is fine when this
 happens

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25461#comment:2>
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