1 /* 2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_GC_SHARED_WORKERPOLICY_HPP 26 #define SHARE_VM_GC_SHARED_WORKERPOLICY_HPP 27 28 #include "memory/allocation.hpp" 29 #include "utilities/globalDefinitions.hpp" 30 31 class 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 46 public: 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_VM_GC_SHARED_WORKERPOLICY_HPP