What exactly are the count and duration values in JFR Thread Contention











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I have an multi-threaded application that runs for 1m9s (with 56 concurrent threads). The JFR screenshot of the contentions is show below. What is not clear to me are:




  1. What does the Count field indicate? The number of times the Lock has been acquired?

  2. What does the Average value indicate? And how is it that the Duration (= count * average) greater than the total execution time of the application?


enter image description here



Thanks,










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    I have an multi-threaded application that runs for 1m9s (with 56 concurrent threads). The JFR screenshot of the contentions is show below. What is not clear to me are:




    1. What does the Count field indicate? The number of times the Lock has been acquired?

    2. What does the Average value indicate? And how is it that the Duration (= count * average) greater than the total execution time of the application?


    enter image description here



    Thanks,










    share|improve this question
























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      I have an multi-threaded application that runs for 1m9s (with 56 concurrent threads). The JFR screenshot of the contentions is show below. What is not clear to me are:




      1. What does the Count field indicate? The number of times the Lock has been acquired?

      2. What does the Average value indicate? And how is it that the Duration (= count * average) greater than the total execution time of the application?


      enter image description here



      Thanks,










      share|improve this question













      I have an multi-threaded application that runs for 1m9s (with 56 concurrent threads). The JFR screenshot of the contentions is show below. What is not clear to me are:




      1. What does the Count field indicate? The number of times the Lock has been acquired?

      2. What does the Average value indicate? And how is it that the Duration (= count * average) greater than the total execution time of the application?


      enter image description here



      Thanks,







      java jfr






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      asked Nov 22 at 3:07









      Sami Hailu

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          If I remember correctly the tab you're looking at there shows the number of times a thread has been blocked waiting on each lock grouped by the class (i.e. it counts multiple instances of the lock as the same here). The reason you might see a cumulative duration longer than the total runtime of the application is that it counts the wait time of each thread. Since you have 56 threads running (assuming that they run for the entire runtime of the application) the maximum amount of time that can be spent blocking on one particular lock is around 64 minutes (69s*56).






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            up vote
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            If I remember correctly the tab you're looking at there shows the number of times a thread has been blocked waiting on each lock grouped by the class (i.e. it counts multiple instances of the lock as the same here). The reason you might see a cumulative duration longer than the total runtime of the application is that it counts the wait time of each thread. Since you have 56 threads running (assuming that they run for the entire runtime of the application) the maximum amount of time that can be spent blocking on one particular lock is around 64 minutes (69s*56).






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              up vote
              2
              down vote













              If I remember correctly the tab you're looking at there shows the number of times a thread has been blocked waiting on each lock grouped by the class (i.e. it counts multiple instances of the lock as the same here). The reason you might see a cumulative duration longer than the total runtime of the application is that it counts the wait time of each thread. Since you have 56 threads running (assuming that they run for the entire runtime of the application) the maximum amount of time that can be spent blocking on one particular lock is around 64 minutes (69s*56).






              share|improve this answer























                up vote
                2
                down vote










                up vote
                2
                down vote









                If I remember correctly the tab you're looking at there shows the number of times a thread has been blocked waiting on each lock grouped by the class (i.e. it counts multiple instances of the lock as the same here). The reason you might see a cumulative duration longer than the total runtime of the application is that it counts the wait time of each thread. Since you have 56 threads running (assuming that they run for the entire runtime of the application) the maximum amount of time that can be spent blocking on one particular lock is around 64 minutes (69s*56).






                share|improve this answer












                If I remember correctly the tab you're looking at there shows the number of times a thread has been blocked waiting on each lock grouped by the class (i.e. it counts multiple instances of the lock as the same here). The reason you might see a cumulative duration longer than the total runtime of the application is that it counts the wait time of each thread. Since you have 56 threads running (assuming that they run for the entire runtime of the application) the maximum amount of time that can be spent blocking on one particular lock is around 64 minutes (69s*56).







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                share|improve this answer










                answered Nov 22 at 10:24









                Henrik Dafgård

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