1/*
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24
25#ifndef SHARE_GC_SHARED_WORKERPOLICY_HPP
26#define SHARE_GC_SHARED_WORKERPOLICY_HPP
27
28#include "memory/allocation.hpp"
29#include "utilities/globalDefinitions.hpp"
30
31class WorkerPolicy : public AllStatic {
32 static const uint GCWorkersPerJavaThread = 2;
33
34 static bool _debug_perturbation;
35 static uint _parallel_worker_threads;
36 static bool _parallel_worker_threads_initialized;
37
38 static uint nof_parallel_worker_threads(uint num,
39 uint den,
40 uint switch_pt);
41
42 // Calculates and returns the number of parallel GC threads. May
43 // be CPU-architecture-specific.
44 static uint calc_parallel_worker_threads();
45
46public:
47 // Returns the number of parallel threads to be used as default value of
48 // ParallelGCThreads. If that number has not been calculated, do so and
49 // save it. Returns ParallelGCThreads if it is set on the
50 // command line.
51 static uint parallel_worker_threads();
52
53 // Return number default GC threads to use in the next GC.
54 static uint calc_default_active_workers(uintx total_workers,
55 const uintx min_workers,
56 uintx active_workers,
57 uintx application_workers);
58
59 // Return number of GC threads to use in the next GC.
60 // This is called sparingly so as not to change the
61 // number of GC workers gratuitously.
62 // For ParNew collections
63 // For PS scavenge and ParOld collections
64 // For G1 evacuation pauses (subject to update)
65 // For G1 Full GCs (subject to update)
66 // Other collection phases inherit the number of
67 // GC workers from the calls above. For example,
68 // a CMS parallel remark uses the same number of GC
69 // workers as the most recent ParNew collection.
70 static uint calc_active_workers(uintx total_workers,
71 uintx active_workers,
72 uintx application_workers);
73
74 // Return number of GC threads to use in the next concurrent GC phase.
75 static uint calc_active_conc_workers(uintx total_workers,
76 uintx active_workers,
77 uintx application_workers);
78
79};
80
81#endif // SHARE_GC_SHARED_WORKERPOLICY_HPP
82