What is the unit of YGCT in jstat output












7















 S0C    S1C    S0U    S1U      EC       EU        OC         OU       MC     MU    CCSC   CCSU   YGC     YGCT    FGC    FGCT     GCT   
245760.0 245760.0 33804.8 0.0 1966080.0 364994.1 8028160.0 138003.6 25984.0 25429.9 2944.0 2877.2 8 0.451 2 0.153 0.603


This is the output of ./jstat -gc pid 250ms 0
I want to know what is the unit YGCT or FGCT? i.e. us or ms?










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    7















     S0C    S1C    S0U    S1U      EC       EU        OC         OU       MC     MU    CCSC   CCSU   YGC     YGCT    FGC    FGCT     GCT   
    245760.0 245760.0 33804.8 0.0 1966080.0 364994.1 8028160.0 138003.6 25984.0 25429.9 2944.0 2877.2 8 0.451 2 0.153 0.603


    This is the output of ./jstat -gc pid 250ms 0
    I want to know what is the unit YGCT or FGCT? i.e. us or ms?










    share|improve this question

























      7












      7








      7








       S0C    S1C    S0U    S1U      EC       EU        OC         OU       MC     MU    CCSC   CCSU   YGC     YGCT    FGC    FGCT     GCT   
      245760.0 245760.0 33804.8 0.0 1966080.0 364994.1 8028160.0 138003.6 25984.0 25429.9 2944.0 2877.2 8 0.451 2 0.153 0.603


      This is the output of ./jstat -gc pid 250ms 0
      I want to know what is the unit YGCT or FGCT? i.e. us or ms?










      share|improve this question














       S0C    S1C    S0U    S1U      EC       EU        OC         OU       MC     MU    CCSC   CCSU   YGC     YGCT    FGC    FGCT     GCT   
      245760.0 245760.0 33804.8 0.0 1966080.0 364994.1 8028160.0 138003.6 25984.0 25429.9 2944.0 2877.2 8 0.451 2 0.153 0.603


      This is the output of ./jstat -gc pid 250ms 0
      I want to know what is the unit YGCT or FGCT? i.e. us or ms?







      jstat






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      asked Jun 10 '15 at 7:48









      Kumar SarasKumar Saras

      7227




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          2 Answers
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          4














          The unit is second according to https://docs.oracle.com/javase/7/docs/technotes/tools/share/jstat.html.



          Is not explicitly stated but it is easy to grasp from the paragraph Using the gcutil option:




          The output of this example shows that a young generation collection
          occurred between the 3rd and 4th sample. The collection took 0.001
          seconds and promoted objects ...




          0.001 is the difference between 2 sequential YGCT because is a young generation collection; search the paragraph at the link above in order to learn more about the context.



          Accepting seconds as the unit for YGCT while considering that would be illogical/confusing to have another for FGCT one could conclude that seconds is also the unit for FGCT.



          UPDATE
          jstat for java 8, jstat for java 9, jstat for java 10 and jstat for java 11 all offer the same example but with other values then here; see The collection took 0.078 seconds paragraph. I stress again that is important to understand what the time measuring is for (YGCT) and why (because is about a young generation collection).






          share|improve this answer


























          • I do not think this is correct. I initially came to the same conclusion from the docs. But look at this output. S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 37376.0 38400.0 0.0 15277.9 6174208.0 2819349.5 2595840.0 2082461.3 87680.0 83317.5 10624.0 9802.4 8293 176.194 5 1.463 177.656 GCT, which I believe should be the sum of the other *GCT values, is 1.463, vs. 8293 and 5. (Sorry cannot figure out how to block format in a comment.)

            – Lorrin
            Mar 7 '18 at 23:30













          • It seems that you are miss interpreting the values. In fact is GCT = YGCT + FGCT so 177.656 ~= 177.657 = 176.194 + 1.463 The 0.001 difference (you’ll notice it in documentation too for GCT) I don’t know exactly where it comes from (from some rounding maybe?). From Using the gcutil option you have YGCT + FGCT = GCT where row3: 0.176 + 0.495 = 0.761 ~= 0.672 and row4: 0.177 + 0.495 = 0.762 ~= 0.673 and GCT4 - GCT3 = 0.673 - 0.672 = 0.001 (according to doc). So because GCT ~= YGCT + FGCT I again conclude YGCT and FGCT are seconds. Still waiting the explanation for the bad reputation mark :).

            – adrhc
            Mar 9 '18 at 5:56








          • 1





            Ha! In monospace in my terminal, it looked visually aligned at casual glance, but it actually wasn't. So I was reading the wrong numbers. I now agree with you. I'll give you my +1, but the -1 wasn't me! :-)

            – Lorrin
            Mar 10 '18 at 18:06











          • I appreciate that you tried to see the value of my answer before deciding to vote :)

            – adrhc
            Sep 29 '18 at 8:39



















          5














          The unit is seconds.



          YGCT - stands for Young generation garbage collection time



          FGCT - stands for Full garbage collection time



          Both values sum up the time the GC takes for the specific task.






          share|improve this answer



















          • 1





            Pumped to find this answer - but what tells you that it's seconds?

            – JoshC13
            Feb 9 '17 at 14:50











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          2 Answers
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          2 Answers
          2






          active

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          active

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          active

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          4














          The unit is second according to https://docs.oracle.com/javase/7/docs/technotes/tools/share/jstat.html.



          Is not explicitly stated but it is easy to grasp from the paragraph Using the gcutil option:




          The output of this example shows that a young generation collection
          occurred between the 3rd and 4th sample. The collection took 0.001
          seconds and promoted objects ...




          0.001 is the difference between 2 sequential YGCT because is a young generation collection; search the paragraph at the link above in order to learn more about the context.



          Accepting seconds as the unit for YGCT while considering that would be illogical/confusing to have another for FGCT one could conclude that seconds is also the unit for FGCT.



          UPDATE
          jstat for java 8, jstat for java 9, jstat for java 10 and jstat for java 11 all offer the same example but with other values then here; see The collection took 0.078 seconds paragraph. I stress again that is important to understand what the time measuring is for (YGCT) and why (because is about a young generation collection).






          share|improve this answer


























          • I do not think this is correct. I initially came to the same conclusion from the docs. But look at this output. S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 37376.0 38400.0 0.0 15277.9 6174208.0 2819349.5 2595840.0 2082461.3 87680.0 83317.5 10624.0 9802.4 8293 176.194 5 1.463 177.656 GCT, which I believe should be the sum of the other *GCT values, is 1.463, vs. 8293 and 5. (Sorry cannot figure out how to block format in a comment.)

            – Lorrin
            Mar 7 '18 at 23:30













          • It seems that you are miss interpreting the values. In fact is GCT = YGCT + FGCT so 177.656 ~= 177.657 = 176.194 + 1.463 The 0.001 difference (you’ll notice it in documentation too for GCT) I don’t know exactly where it comes from (from some rounding maybe?). From Using the gcutil option you have YGCT + FGCT = GCT where row3: 0.176 + 0.495 = 0.761 ~= 0.672 and row4: 0.177 + 0.495 = 0.762 ~= 0.673 and GCT4 - GCT3 = 0.673 - 0.672 = 0.001 (according to doc). So because GCT ~= YGCT + FGCT I again conclude YGCT and FGCT are seconds. Still waiting the explanation for the bad reputation mark :).

            – adrhc
            Mar 9 '18 at 5:56








          • 1





            Ha! In monospace in my terminal, it looked visually aligned at casual glance, but it actually wasn't. So I was reading the wrong numbers. I now agree with you. I'll give you my +1, but the -1 wasn't me! :-)

            – Lorrin
            Mar 10 '18 at 18:06











          • I appreciate that you tried to see the value of my answer before deciding to vote :)

            – adrhc
            Sep 29 '18 at 8:39
















          4














          The unit is second according to https://docs.oracle.com/javase/7/docs/technotes/tools/share/jstat.html.



          Is not explicitly stated but it is easy to grasp from the paragraph Using the gcutil option:




          The output of this example shows that a young generation collection
          occurred between the 3rd and 4th sample. The collection took 0.001
          seconds and promoted objects ...




          0.001 is the difference between 2 sequential YGCT because is a young generation collection; search the paragraph at the link above in order to learn more about the context.



          Accepting seconds as the unit for YGCT while considering that would be illogical/confusing to have another for FGCT one could conclude that seconds is also the unit for FGCT.



          UPDATE
          jstat for java 8, jstat for java 9, jstat for java 10 and jstat for java 11 all offer the same example but with other values then here; see The collection took 0.078 seconds paragraph. I stress again that is important to understand what the time measuring is for (YGCT) and why (because is about a young generation collection).






          share|improve this answer


























          • I do not think this is correct. I initially came to the same conclusion from the docs. But look at this output. S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 37376.0 38400.0 0.0 15277.9 6174208.0 2819349.5 2595840.0 2082461.3 87680.0 83317.5 10624.0 9802.4 8293 176.194 5 1.463 177.656 GCT, which I believe should be the sum of the other *GCT values, is 1.463, vs. 8293 and 5. (Sorry cannot figure out how to block format in a comment.)

            – Lorrin
            Mar 7 '18 at 23:30













          • It seems that you are miss interpreting the values. In fact is GCT = YGCT + FGCT so 177.656 ~= 177.657 = 176.194 + 1.463 The 0.001 difference (you’ll notice it in documentation too for GCT) I don’t know exactly where it comes from (from some rounding maybe?). From Using the gcutil option you have YGCT + FGCT = GCT where row3: 0.176 + 0.495 = 0.761 ~= 0.672 and row4: 0.177 + 0.495 = 0.762 ~= 0.673 and GCT4 - GCT3 = 0.673 - 0.672 = 0.001 (according to doc). So because GCT ~= YGCT + FGCT I again conclude YGCT and FGCT are seconds. Still waiting the explanation for the bad reputation mark :).

            – adrhc
            Mar 9 '18 at 5:56








          • 1





            Ha! In monospace in my terminal, it looked visually aligned at casual glance, but it actually wasn't. So I was reading the wrong numbers. I now agree with you. I'll give you my +1, but the -1 wasn't me! :-)

            – Lorrin
            Mar 10 '18 at 18:06











          • I appreciate that you tried to see the value of my answer before deciding to vote :)

            – adrhc
            Sep 29 '18 at 8:39














          4












          4








          4







          The unit is second according to https://docs.oracle.com/javase/7/docs/technotes/tools/share/jstat.html.



          Is not explicitly stated but it is easy to grasp from the paragraph Using the gcutil option:




          The output of this example shows that a young generation collection
          occurred between the 3rd and 4th sample. The collection took 0.001
          seconds and promoted objects ...




          0.001 is the difference between 2 sequential YGCT because is a young generation collection; search the paragraph at the link above in order to learn more about the context.



          Accepting seconds as the unit for YGCT while considering that would be illogical/confusing to have another for FGCT one could conclude that seconds is also the unit for FGCT.



          UPDATE
          jstat for java 8, jstat for java 9, jstat for java 10 and jstat for java 11 all offer the same example but with other values then here; see The collection took 0.078 seconds paragraph. I stress again that is important to understand what the time measuring is for (YGCT) and why (because is about a young generation collection).






          share|improve this answer















          The unit is second according to https://docs.oracle.com/javase/7/docs/technotes/tools/share/jstat.html.



          Is not explicitly stated but it is easy to grasp from the paragraph Using the gcutil option:




          The output of this example shows that a young generation collection
          occurred between the 3rd and 4th sample. The collection took 0.001
          seconds and promoted objects ...




          0.001 is the difference between 2 sequential YGCT because is a young generation collection; search the paragraph at the link above in order to learn more about the context.



          Accepting seconds as the unit for YGCT while considering that would be illogical/confusing to have another for FGCT one could conclude that seconds is also the unit for FGCT.



          UPDATE
          jstat for java 8, jstat for java 9, jstat for java 10 and jstat for java 11 all offer the same example but with other values then here; see The collection took 0.078 seconds paragraph. I stress again that is important to understand what the time measuring is for (YGCT) and why (because is about a young generation collection).







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 25 '18 at 11:44

























          answered Feb 12 '18 at 13:18









          adrhcadrhc

          505314




          505314













          • I do not think this is correct. I initially came to the same conclusion from the docs. But look at this output. S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 37376.0 38400.0 0.0 15277.9 6174208.0 2819349.5 2595840.0 2082461.3 87680.0 83317.5 10624.0 9802.4 8293 176.194 5 1.463 177.656 GCT, which I believe should be the sum of the other *GCT values, is 1.463, vs. 8293 and 5. (Sorry cannot figure out how to block format in a comment.)

            – Lorrin
            Mar 7 '18 at 23:30













          • It seems that you are miss interpreting the values. In fact is GCT = YGCT + FGCT so 177.656 ~= 177.657 = 176.194 + 1.463 The 0.001 difference (you’ll notice it in documentation too for GCT) I don’t know exactly where it comes from (from some rounding maybe?). From Using the gcutil option you have YGCT + FGCT = GCT where row3: 0.176 + 0.495 = 0.761 ~= 0.672 and row4: 0.177 + 0.495 = 0.762 ~= 0.673 and GCT4 - GCT3 = 0.673 - 0.672 = 0.001 (according to doc). So because GCT ~= YGCT + FGCT I again conclude YGCT and FGCT are seconds. Still waiting the explanation for the bad reputation mark :).

            – adrhc
            Mar 9 '18 at 5:56








          • 1





            Ha! In monospace in my terminal, it looked visually aligned at casual glance, but it actually wasn't. So I was reading the wrong numbers. I now agree with you. I'll give you my +1, but the -1 wasn't me! :-)

            – Lorrin
            Mar 10 '18 at 18:06











          • I appreciate that you tried to see the value of my answer before deciding to vote :)

            – adrhc
            Sep 29 '18 at 8:39



















          • I do not think this is correct. I initially came to the same conclusion from the docs. But look at this output. S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 37376.0 38400.0 0.0 15277.9 6174208.0 2819349.5 2595840.0 2082461.3 87680.0 83317.5 10624.0 9802.4 8293 176.194 5 1.463 177.656 GCT, which I believe should be the sum of the other *GCT values, is 1.463, vs. 8293 and 5. (Sorry cannot figure out how to block format in a comment.)

            – Lorrin
            Mar 7 '18 at 23:30













          • It seems that you are miss interpreting the values. In fact is GCT = YGCT + FGCT so 177.656 ~= 177.657 = 176.194 + 1.463 The 0.001 difference (you’ll notice it in documentation too for GCT) I don’t know exactly where it comes from (from some rounding maybe?). From Using the gcutil option you have YGCT + FGCT = GCT where row3: 0.176 + 0.495 = 0.761 ~= 0.672 and row4: 0.177 + 0.495 = 0.762 ~= 0.673 and GCT4 - GCT3 = 0.673 - 0.672 = 0.001 (according to doc). So because GCT ~= YGCT + FGCT I again conclude YGCT and FGCT are seconds. Still waiting the explanation for the bad reputation mark :).

            – adrhc
            Mar 9 '18 at 5:56








          • 1





            Ha! In monospace in my terminal, it looked visually aligned at casual glance, but it actually wasn't. So I was reading the wrong numbers. I now agree with you. I'll give you my +1, but the -1 wasn't me! :-)

            – Lorrin
            Mar 10 '18 at 18:06











          • I appreciate that you tried to see the value of my answer before deciding to vote :)

            – adrhc
            Sep 29 '18 at 8:39

















          I do not think this is correct. I initially came to the same conclusion from the docs. But look at this output. S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 37376.0 38400.0 0.0 15277.9 6174208.0 2819349.5 2595840.0 2082461.3 87680.0 83317.5 10624.0 9802.4 8293 176.194 5 1.463 177.656 GCT, which I believe should be the sum of the other *GCT values, is 1.463, vs. 8293 and 5. (Sorry cannot figure out how to block format in a comment.)

          – Lorrin
          Mar 7 '18 at 23:30







          I do not think this is correct. I initially came to the same conclusion from the docs. But look at this output. S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 37376.0 38400.0 0.0 15277.9 6174208.0 2819349.5 2595840.0 2082461.3 87680.0 83317.5 10624.0 9802.4 8293 176.194 5 1.463 177.656 GCT, which I believe should be the sum of the other *GCT values, is 1.463, vs. 8293 and 5. (Sorry cannot figure out how to block format in a comment.)

          – Lorrin
          Mar 7 '18 at 23:30















          It seems that you are miss interpreting the values. In fact is GCT = YGCT + FGCT so 177.656 ~= 177.657 = 176.194 + 1.463 The 0.001 difference (you’ll notice it in documentation too for GCT) I don’t know exactly where it comes from (from some rounding maybe?). From Using the gcutil option you have YGCT + FGCT = GCT where row3: 0.176 + 0.495 = 0.761 ~= 0.672 and row4: 0.177 + 0.495 = 0.762 ~= 0.673 and GCT4 - GCT3 = 0.673 - 0.672 = 0.001 (according to doc). So because GCT ~= YGCT + FGCT I again conclude YGCT and FGCT are seconds. Still waiting the explanation for the bad reputation mark :).

          – adrhc
          Mar 9 '18 at 5:56







          It seems that you are miss interpreting the values. In fact is GCT = YGCT + FGCT so 177.656 ~= 177.657 = 176.194 + 1.463 The 0.001 difference (you’ll notice it in documentation too for GCT) I don’t know exactly where it comes from (from some rounding maybe?). From Using the gcutil option you have YGCT + FGCT = GCT where row3: 0.176 + 0.495 = 0.761 ~= 0.672 and row4: 0.177 + 0.495 = 0.762 ~= 0.673 and GCT4 - GCT3 = 0.673 - 0.672 = 0.001 (according to doc). So because GCT ~= YGCT + FGCT I again conclude YGCT and FGCT are seconds. Still waiting the explanation for the bad reputation mark :).

          – adrhc
          Mar 9 '18 at 5:56






          1




          1





          Ha! In monospace in my terminal, it looked visually aligned at casual glance, but it actually wasn't. So I was reading the wrong numbers. I now agree with you. I'll give you my +1, but the -1 wasn't me! :-)

          – Lorrin
          Mar 10 '18 at 18:06





          Ha! In monospace in my terminal, it looked visually aligned at casual glance, but it actually wasn't. So I was reading the wrong numbers. I now agree with you. I'll give you my +1, but the -1 wasn't me! :-)

          – Lorrin
          Mar 10 '18 at 18:06













          I appreciate that you tried to see the value of my answer before deciding to vote :)

          – adrhc
          Sep 29 '18 at 8:39





          I appreciate that you tried to see the value of my answer before deciding to vote :)

          – adrhc
          Sep 29 '18 at 8:39













          5














          The unit is seconds.



          YGCT - stands for Young generation garbage collection time



          FGCT - stands for Full garbage collection time



          Both values sum up the time the GC takes for the specific task.






          share|improve this answer



















          • 1





            Pumped to find this answer - but what tells you that it's seconds?

            – JoshC13
            Feb 9 '17 at 14:50
















          5














          The unit is seconds.



          YGCT - stands for Young generation garbage collection time



          FGCT - stands for Full garbage collection time



          Both values sum up the time the GC takes for the specific task.






          share|improve this answer



















          • 1





            Pumped to find this answer - but what tells you that it's seconds?

            – JoshC13
            Feb 9 '17 at 14:50














          5












          5








          5







          The unit is seconds.



          YGCT - stands for Young generation garbage collection time



          FGCT - stands for Full garbage collection time



          Both values sum up the time the GC takes for the specific task.






          share|improve this answer













          The unit is seconds.



          YGCT - stands for Young generation garbage collection time



          FGCT - stands for Full garbage collection time



          Both values sum up the time the GC takes for the specific task.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Jul 21 '15 at 11:20









          LogarithLogarith

          4781522




          4781522








          • 1





            Pumped to find this answer - but what tells you that it's seconds?

            – JoshC13
            Feb 9 '17 at 14:50














          • 1





            Pumped to find this answer - but what tells you that it's seconds?

            – JoshC13
            Feb 9 '17 at 14:50








          1




          1





          Pumped to find this answer - but what tells you that it's seconds?

          – JoshC13
          Feb 9 '17 at 14:50





          Pumped to find this answer - but what tells you that it's seconds?

          – JoshC13
          Feb 9 '17 at 14:50


















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