1 /* 2 * Copyright (c) 2018, Red Hat, Inc. and/or its affiliates. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHPACER_HPP 25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHPACER_HPP 26 27 #include "memory/allocation.hpp" 28 #include "utilities/numberSeq.hpp" 29 30 class ShenandoahHeap; 31 32 #define PACING_PROGRESS_UNINIT (-1) 33 #define PACING_PROGRESS_ZERO ( 0) 34 35 /** 36 * ShenandoahPacer provides allocation pacing mechanism. 37 * 38 * Currently it implements simple tax-and-spend pacing policy: GC threads provide 39 * credit, allocating thread spend the credit, or stall when credit is not available. 40 */ 41 class ShenandoahPacer : public CHeapObj<mtGC> { 42 private: 43 ShenandoahHeap* _heap; 44 volatile intptr_t _budget; 45 volatile jdouble _tax_rate; 46 BinaryMagnitudeSeq _delays; 47 48 volatile intptr_t _progress; 49 TruncatedSeq* _progress_history; 50 volatile intptr_t _epoch; 51 52 public: 53 ShenandoahPacer(ShenandoahHeap* heap) : 54 _heap(heap), _budget(0), _tax_rate(1), 55 _progress(PACING_PROGRESS_UNINIT), 56 _progress_history(new TruncatedSeq(5)), 57 _epoch(0) { 58 } 59 60 void setup_for_idle(); 61 void setup_for_mark(); 62 void setup_for_evac(); 63 void setup_for_updaterefs(); 64 65 inline void report_mark(size_t words); 66 inline void report_evac(size_t words); 67 inline void report_updaterefs(size_t words); 68 69 inline void report_alloc(size_t words); 70 71 bool claim_for_alloc(size_t words, bool force); 72 void pace_for_alloc(size_t words); 73 void unpace_for_alloc(intptr_t epoch, size_t words); 74 75 intptr_t epoch(); 76 77 void print_on(outputStream* out) const; 78 79 private: 80 inline void report_internal(size_t words); 81 inline void report_progress_internal(size_t words); 82 83 void restart_with(jlong non_taxable_bytes, jdouble tax_rate); 84 85 size_t update_and_get_progress_history(); 86 }; 87 88 #endif //SHARE_VM_GC_SHENANDOAH_SHENANDOAHPACER_HPP