1 /* 2 * Copyright (c) 2018, 2019, Red Hat, Inc. 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_GC_SHENANDOAH_SHENANDOAHPACER_HPP 26 #define SHARE_GC_SHENANDOAH_SHENANDOAHPACER_HPP 27 28 #include "gc/shenandoah/shenandoahNumberSeq.hpp" 29 #include "gc/shenandoah/shenandoahPadding.hpp" 30 #include "memory/allocation.hpp" 31 32 class ShenandoahHeap; 33 34 #define PACING_PROGRESS_UNINIT (-1) 35 #define PACING_PROGRESS_ZERO ( 0) 36 37 /** 38 * ShenandoahPacer provides allocation pacing mechanism. 39 * 40 * Currently it implements simple tax-and-spend pacing policy: GC threads provide 41 * credit, allocating thread spend the credit, or stall when credit is not available. 42 */ 43 class ShenandoahPacer : public CHeapObj<mtGC> { 44 private: 45 ShenandoahHeap* _heap; 46 BinaryMagnitudeSeq _delays; 47 TruncatedSeq* _progress_history; 48 49 // Set once per phase 50 volatile intptr_t _epoch; 51 volatile double _tax_rate; 52 53 // Heavily updated, protect from accidental false sharing 54 shenandoah_padding(0); 55 volatile intptr_t _budget; 56 shenandoah_padding(1); 57 58 // Heavily updated, protect from accidental false sharing 59 shenandoah_padding(2); 60 volatile intptr_t _progress; 61 shenandoah_padding(3); 62 63 public: 64 ShenandoahPacer(ShenandoahHeap* heap) : 65 _heap(heap), 66 _progress_history(new TruncatedSeq(5)), 67 _epoch(0), 68 _tax_rate(1), 69 _budget(0), 70 _progress(PACING_PROGRESS_UNINIT) {} 71 72 void setup_for_idle(); 73 void setup_for_mark(); 74 void setup_for_evac(); 75 void setup_for_updaterefs(); 76 77 void setup_for_reset(); 78 void setup_for_preclean(); 79 80 inline void report_mark(size_t words); 81 inline void report_evac(size_t words); 82 inline void report_updaterefs(size_t words); 83 84 inline void report_alloc(size_t words); 85 86 bool claim_for_alloc(size_t words, bool force); 87 void pace_for_alloc(size_t words); 88 void unpace_for_alloc(intptr_t epoch, size_t words); 89 90 intptr_t epoch(); 91 92 void print_on(outputStream* out) const; 93 94 private: 95 inline void report_internal(size_t words); 96 inline void report_progress_internal(size_t words); 97 98 void restart_with(size_t non_taxable_bytes, double tax_rate); 99 100 size_t update_and_get_progress_history(); 101 }; 102 103 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHPACER_HPP