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bug #7938

Updated by Andreas Kohlbecker over 5 years ago

This performance problem was observed at the edit production server but might also affect other installations. 

 Users where complaining about the server being very slow since a couple of days. 

 The reason for the server being "slow" is that two sub processes are consuming 100% CPU time of one cpu core each. 

 ![](Screenshot_20181205_112519.png) 
 ![](Screenshot_20181205_112425.png) 

 The cpu load is produced by the to subprocesses with the PIDs **9527** and **9528** 

 A stake trace with native frames included give first insight into what these processes are doing (attachment:jstack-with-native-frames.tdump): 

 ~~~ 
 ----------------- 9527 ----------------- 
 0x00007fe4a30c8f10    _ZNK7MemNode20can_see_stored_valueEP4NodeP14PhaseTransform + 0x2c0 
 0x00007fe4a30c9c74    _ZNK8LoadNode5ValueEP14PhaseTransform + 0xf4 
 0x00007fe4a31ac87a    _ZN12PhaseIterGVN13transform_oldEP4Node + 0xea 
 0x00007fe4a31a9fcc    _ZN12PhaseIterGVN8optimizeEv + 0x1bc 
 0x00007fe4a2ce51a9    _ZN7Compile8OptimizeEv + 0x159 
 0x00007fe4a2ce6fea    _ZN7CompileC1EP5ciEnvP10C2CompilerP8ciMethodibbb + 0x13ca 
 0x00007fe4a2c34818    _ZN10C2Compiler14compile_methodEP5ciEnvP8ciMethodi + 0x198 
 0x00007fe4a2cf14da    _ZN13CompileBroker25invoke_compiler_on_methodEP11CompileTask + 0xc9a 
 0x00007fe4a2cf2486    _ZN13CompileBroker20compiler_thread_loopEv + 0x5d6 
 0x00007fe4a32ae77f    _ZN10JavaThread17thread_main_innerEv + 0xdf 
 0x00007fe4a32ae8ac    _ZN10JavaThread3runEv + 0x11c 
 0x00007fe4a3161f78    _ZL10java_startP6Thread + 0x108 
 ----------------- 9528 ----------------- 
 0x00007fe4a30c8ed6    _ZNK7MemNode20can_see_stored_valueEP4NodeP14PhaseTransform + 0x286 
 0x00007fe4a30c9c74    _ZNK8LoadNode5ValueEP14PhaseTransform + 0xf4 
 0x00007fe4a31ac87a    _ZN12PhaseIterGVN13transform_oldEP4Node + 0xea 
 0x00007fe4a31a9fcc    _ZN12PhaseIterGVN8optimizeEv + 0x1bc 
 0x00007fe4a2ce51a9    _ZN7Compile8OptimizeEv + 0x159 
 0x00007fe4a2ce6fea    _ZN7CompileC1EP5ciEnvP10C2CompilerP8ciMethodibbb + 0x13ca 
 0x00007fe4a2c34818    _ZN10C2Compiler14compile_methodEP5ciEnvP8ciMethodi + 0x198 
 0x00007fe4a2cf14da    _ZN13CompileBroker25invoke_compiler_on_methodEP11CompileTask + 0xc9a 
 0x00007fe4a2cf2486    _ZN13CompileBroker20compiler_thread_loopEv + 0x5d6 
 0x00007fe4a32ae77f    _ZN10JavaThread17thread_main_innerEv + 0xdf 
 0x00007fe4a32ae8ac    _ZN10JavaThread3runEv + 0x11c 
 0x00007fe4a3161f78    _ZL10java_startP6Thread + 0x108 

 ~~~ 

   




 




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