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IV62265: LONG PAUSE GC IN JIT RUNTIME ASSUMPTION TABLE RECLAIM

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APAR status

  • Closed as program error.

Error description

  • Error Message: 1. Application performance suddenly drops.2. GC
verbose log shows long GC end durtion<exclusive-end id="531"
timestamp="2014-01-09T11:45:56.780" durationms="43671.669" />3.
When long pause happens, GC threads call stack in JIT module and
JIT-AssumptionTableMutex lock is locked in GC thread.
.
Stack Trace: 4XENATIVESTACK               (0x00007F88410DBD43
<OSB>libj9jit27.so+0x65fd43<CSB>)4XENATIVESTACK
(0x00007F88410DCDFB
<OSB>libj9jit27.so+0x660dfb<CSB>)4XENATIVESTACK
(0x00007F88410E17C4
<OSB>libj9jit27.so+0x6657c4<CSB>)4XENATIVESTACK
(0x00007F8840B5DE92
<OSB>libj9jit27.so+0xe1e92<CSB>)4XENATIVESTACK
(0x00007F8842AC0D6B
<OSB>libj9hookable27.so+0xd6b<CSB>)4XENATIVESTACK
(0x00007F88404A0495
<OSB>libj9gc27.so+0x149495<CSB>)4XENATIVESTACK
(0x00007F88404A67EF
<OSB>libj9gc27.so+0x14f7ef<CSB>)4XENATIVESTACK
(0x00007F88404A6C37
<OSB>libj9gc27.so+0x14fc37<CSB>)4XENATIVESTACK
(0x00007F88404AA62E
<OSB>libj9gc27.so+0x15362e<CSB>)4XENATIVESTACK
(0x00007F88404B434E <OSB>libj9gc27.so+0x15d34e<CSB>)
.

Local fix

  • -Xjit:disableCodeCacheReclamation -Xnoclassgc, this will avoid
invoke runtime assumption table reclaim and might increase
memory usage

Problem summary

  • GC end hook spent time in JIT runtime assumption table reclaim.
Runtime assumption table is not balanced hashtable and cause
long time traverse.

Problem conclusion

  • JVM update JIT runtime assumption hash table algorithm and
hastable is balanced. This avoids long time traverse.
.
This APAR will be fixed in the following Java Releases:
   7 R1 SR1 FP1   (7.1.1.1)
.
Contact your IBM Product's Service Team for these Service
Refreshes and Fix Packs.
For those running stand-alone, Java maintenance is available
from:
           https://www.ibm.com/developerworks/java/jdk/

Temporary fix

  • 



Comments


    

  • 



APAR Information




    

  • APAR number
    IV62265
    • 

  • Reported component name
    JIT
    • 

  • Reported component ID
    620700124
    • 

  • Reported release
    130
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Special Attention
    NoSpecatt
    • 

  • Submitted date
    2014-07-04
    • 

  • Closed date
    2014-07-04
    • 

  • Last modified date
    2014-07-04
    • 





    

  • APAR is sysrouted FROM one or more of the following:
    

    • 

  • APAR is sysrouted TO one or more of the following:
    

    • 



Fix information


    

  • Fixed component name
    JIT
    • 

  • Fixed component ID
    620700124
    • 



Applicable component levels


    

  • R130  PSY
       UP
    • 








      
              
                            

              

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Document Information


            

            


                        

            Modified date:
            

            04 July 2014
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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