RFR: 8294759: Print actual lock/monitor ranking

Coleen Phillimore coleenp at openjdk.org
Tue Oct 4 17:37:33 UTC 2022


On Tue, 4 Oct 2022 12:46:42 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> When relative lock ranks are changing, it is useful to see what are the final lock ranks are. It can be dumped as optional logging shortly after VM startup. 
> 
> Sample output:
> 
> 
> $ build/linux-x86_64-server-fastdebug/images/jdk/bin/java -Xlog:vmmutex
> [0.073s][info][vmmutex] VM Mutex/Monitor ranks: 
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "service-2":
> [0.073s][info][vmmutex]   Uncommit_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "service-1":
> [0.073s][info][vmmutex]   FreeList_lock
> [0.073s][info][vmmutex]   MonitoringSupport_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "service":
> [0.073s][info][vmmutex]   Service_lock
> [0.073s][info][vmmutex]   Notification_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "stackwatermark-1":
> [0.073s][info][vmmutex]   JfrStacktrace_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "tty-1":
> [0.073s][info][vmmutex]   SharedDecoder_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "tty":
> [0.073s][info][vmmutex]   tty_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "nosafepoint-3":
> [0.073s][info][vmmutex]   Metaspace_lock
> [0.073s][info][vmmutex]   JfrMsg_lock
> [0.073s][info][vmmutex]   ContinuationRelativize_lock
> [0.073s][info][vmmutex]   ThreadsSMRDelete_lock
> [0.073s][info][vmmutex]   CompiledMethod_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "nosafepoint-2":
> [0.073s][info][vmmutex]   G1DetachedRefinementStats_lock
> [0.073s][info][vmmutex]   JmethodIdCreation_lock
> [0.073s][info][vmmutex]   CodeCache_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "nosafepoint-1":
> [0.073s][info][vmmutex]   RootRegionScan_lock
> [0.073s][info][vmmutex]   RawMonitor_lock
> [0.073s][info][vmmutex]   MetaspaceCritical_lock
> [0.073s][info][vmmutex]   NonJavaThreadsList_lock
> [0.073s][info][vmmutex]   Zip_lock
> [0.073s][info][vmmutex]   InlineCacheBuffer_lock
> [0.073s][info][vmmutex]   VtableStubs_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "nosafepoint":
> [0.073s][info][vmmutex]   STS_lock
> [0.073s][info][vmmutex]   CGC_lock
> [0.073s][info][vmmutex]   OldSets_lock
> [0.073s][info][vmmutex]   MarkStackFreeList_lock
> [0.073s][info][vmmutex]   MarkStackChunkList_lock
> [0.073s][info][vmmutex]   StringDedup_lock
> [0.073s][info][vmmutex]   StringDedupIntern_lock
> [0.073s][info][vmmutex]   Patching_lock
> [0.073s][info][vmmutex]   MonitorDeflation_lock
> [0.073s][info][vmmutex]   SymbolArena_lock
> [0.073s][info][vmmutex]   NonJavaThreadsListSync_lock
> [0.073s][info][vmmutex]   InitCompleted_lock
> [0.073s][info][vmmutex]   CompiledIC_lock
> [0.073s][info][vmmutex]   DirectivesStack_lock
> [0.073s][info][vmmutex]   EscapeBarrier_lock
> [0.073s][info][vmmutex]   JvmtiVTMSTransition_lock
> [0.073s][info][vmmutex]   JfrBuffer_lock
> [0.073s][info][vmmutex]   JfrThreadSampler_lock
> [0.073s][info][vmmutex]   DCmdFactory_lock
> [0.073s][info][vmmutex]   DumpTimeTable_lock
> [0.073s][info][vmmutex]   CDSLambda_lock
> [0.073s][info][vmmutex]   DumpRegion_lock
> [0.073s][info][vmmutex]   ClassListFile_lock
> [0.073s][info][vmmutex]   Bootclasspath_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "safepoint-3":
> [0.073s][info][vmmutex]   PerfDataMemAlloc_lock
> [0.073s][info][vmmutex]   PerfDataManager_lock
> [0.073s][info][vmmutex]   VMOperation_lock
> [0.073s][info][vmmutex]   SystemDictionary_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "safepoint-2":
> [0.073s][info][vmmutex]   Heap_lock
> [0.073s][info][vmmutex]   ClassInitError_lock
> [0.073s][info][vmmutex]   G1OldGCCount_lock
> [0.073s][info][vmmutex]   ParGCRareEvent_lock
> [0.073s][info][vmmutex]   OopMapCacheAlloc_lock
> [0.073s][info][vmmutex]   Module_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "safepoint-1":
> [0.073s][info][vmmutex]   Threads_lock
> [0.073s][info][vmmutex]   Compile_lock
> [0.073s][info][vmmutex]   AdapterHandlerLibrary_lock
> [0.073s][info][vmmutex]   ClassLoaderDataGraph_lock
> [0.073s][info][vmmutex]   CompileTaskAlloc_lock
> [0.073s][info][vmmutex]   JNICritical_lock
> [0.073s][info][vmmutex]   JVMCI_lock
> [0.073s][info][vmmutex] 
> [0.073s][info][vmmutex] Rank "safepoint":
> [0.073s][info][vmmutex]   InvokeMethodTable_lock
> [0.073s][info][vmmutex]   SharedDictionary_lock
> [0.073s][info][vmmutex]   VMStatistic_lock
> [0.073s][info][vmmutex]   SignatureHandlerLibrary_lock
> [0.073s][info][vmmutex]   ExceptionCache_lock
> [0.073s][info][vmmutex]   FullGCALot_lock
> [0.073s][info][vmmutex]   BeforeExit_lock
> [0.073s][info][vmmutex]   RetData_lock
> [0.073s][info][vmmutex]   Terminator_lock
> [0.073s][info][vmmutex]   Notify_lock
> [0.073s][info][vmmutex]   Heap_lock
> [0.073s][info][vmmutex]   JfieldIdCreation_lock
> [0.073s][info][vmmutex]   MethodCompileQueue_lock
> [0.073s][info][vmmutex]   CompileStatistics_lock
> [0.073s][info][vmmutex]   MultiArray_lock
> [0.073s][info][vmmutex]   JvmtiThreadState_lock
> [0.073s][info][vmmutex]   Management_lock
> [0.073s][info][vmmutex]   ConcurrentGCBreakpoints_lock
> [0.073s][info][vmmutex]   MethodData_lock
> [0.073s][info][vmmutex]   TouchedMethodLog_lock
> [0.073s][info][vmmutex]   CompileThread_lock
> [0.073s][info][vmmutex]   PeriodicTask_lock
> [0.073s][info][vmmutex]   RedefineClasses_lock
> [0.073s][info][vmmutex]   Verify_lock
> [0.073s][info][vmmutex]   CodeHeapStateAnalytics_lock
> [0.073s][info][vmmutex]   ThreadIdTableCreate_lock
> [0.073s][info][vmmutex]   NMTQuery_lock
> [0.073s][info][vmmutex]   CDSClassFileStream_lock
> [0.073s][info][vmmutex]   LambdaFormInvokers_lock
> [0.073s][info][vmmutex]   JVMCIRuntime_lock
> 
> 
> Additional testing:
>  - [x] New test on Linux x86_64 {release,fastdebug,slowdebug}

This seems nice.

src/hotspot/share/runtime/mutexLocker.cpp line 440:

> 438:   }
> 439: 
> 440:   for (int r = min_rank; r <= max_rank; r++) {

I'm confused by this first loop. why can't min_rank be Mutex::event or static_cast<int>0 and max_rank should be Mutex::safepoint.

-------------

Marked as reviewed by coleenp (Reviewer).

PR: https://git.openjdk.org/jdk/pull/10556


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