src/hotspot/share/gc/shared/workerPolicy.hpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
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#ifndef SHARE_GC_SHARED_WORKERPOLICY_HPP
#define SHARE_GC_SHARED_WORKERPOLICY_HPP

#include "memory/allStatic.hpp"
#include "utilities/globalDefinitions.hpp"

class WorkerPolicy : public AllStatic {
  static const uint GCWorkersPerJavaThread = 2;

  static uint _parallel_worker_threads;
  static bool _parallel_worker_threads_initialized;

  static uint nof_parallel_worker_threads(uint num,
                                          uint den,
                                          uint switch_pt);

  // Calculates and returns the number of parallel GC threads. May
  // be CPU-architecture-specific.
  static uint calc_parallel_worker_threads();

public:
  // Returns the number of parallel threads to be used as default value of
  // ParallelGCThreads. If that number has not been calculated, do so and
  // save it.  Returns ParallelGCThreads if it is set on the
  // command line.
  static uint parallel_worker_threads();

  // Return number default GC threads to use in the next GC.
  static uint calc_default_active_workers(uintx total_workers,
                                          const uintx min_workers,
                                          uintx active_workers,
                                          uintx application_workers);

  // Return number of GC threads to use in the next GC.
  // This is called sparingly so as not to change the
  // number of GC workers gratuitously.
  //   For PS scavenge and ParOld collections
  //   For G1 evacuation pauses (subject to update)
  //   For G1 Full GCs (subject to update)
  // Other collection phases inherit the number of
  // GC workers from the calls above.
  static uint calc_active_workers(uintx total_workers,
                                  uintx active_workers,
                                  uintx application_workers);

  // Return number of GC threads to use in the next concurrent GC phase.
  static uint calc_active_conc_workers(uintx total_workers,
                                       uintx active_workers,
                                       uintx application_workers);

};

#endif // SHARE_GC_SHARED_WORKERPOLICY_HPP