1 /* 2 * Copyright (c) 2017, 2018, 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_EPSILON_EPSILON_GLOBALS_HPP 26 #define SHARE_GC_EPSILON_EPSILON_GLOBALS_HPP 27 28 #include "runtime/globals_shared.hpp" 29 30 // 31 // Defines all globals flags used by the Epsilon GC. 32 // 33 34 #define GC_EPSILON_FLAGS(develop, \ 35 develop_pd, \ 36 product, \ 37 product_pd, \ 38 diagnostic, \ 39 diagnostic_pd, \ 40 experimental, \ 41 notproduct, \ 42 manageable, \ 43 product_rw, \ 44 lp64_product, \ 45 range, \ 46 constraint, \ 47 writeable) \ 48 \ 49 experimental(size_t, EpsilonPrintHeapSteps, 20, \ 50 "Print heap occupancy stats with this number of steps. " \ 51 "0 turns the printing off.") \ 52 range(0, max_intx) \ 53 \ 54 experimental(size_t, EpsilonUpdateCountersStep, 1 * M, \ 55 "Update heap occupancy counters after allocating this much " \ 56 "memory. Higher values would make allocations faster at " \ 57 "the expense of lower resolution in heap counters.") \ 58 range(1, max_intx) \ 59 \ 60 experimental(size_t, EpsilonMaxTLABSize, 4 * M, \ 61 "Max TLAB size to use with Epsilon GC. Larger value improves " \ 62 "performance at the expense of per-thread memory waste. This " \ 63 "asks TLAB machinery to cap TLAB sizes at this value.") \ 64 range(1, max_intx) \ 65 \ 66 experimental(bool, EpsilonElasticTLAB, true, \ 67 "Use elastic policy to manage TLAB sizes. This conserves memory " \ 68 "for non-actively allocating threads, even when they request " \ 69 "large TLABs for themselves. Active threads would experience " \ 70 "smaller TLABs until policy catches up.") \ 71 \ 72 experimental(bool, EpsilonElasticTLABDecay, true, \ 73 "Use timed decays to shrik TLAB sizes. This conserves memory " \ 74 "for the threads that allocate in bursts of different sizes, " \ 75 "for example the small/rare allocations coming after the initial "\ 76 "large burst.") \ 77 \ 78 experimental(double, EpsilonTLABElasticity, 1.1, \ 79 "Multiplier to use when deciding on next TLAB size. Larger value "\ 80 "improves performance at the expense of per-thread memory waste. "\ 81 "Lower value improves memory footprint, but penalizes actively " \ 82 "allocating threads.") \ 83 range(1.0, DBL_MAX) \ 84 \ 85 experimental(size_t, EpsilonTLABDecayTime, 1000, \ 86 "TLAB sizing policy decays to initial size after thread had not " \ 87 "allocated for this long. Time is in milliseconds. Lower value " \ 88 "improves memory footprint, but penalizes actively allocating " \ 89 "threads.") \ 90 range(1, max_intx) \ 91 \ 92 experimental(size_t, EpsilonMinHeapExpand, 128 * M, \ 93 "Min expansion step for heap. Larger value improves performance " \ 94 "at the potential expense of memory waste.") \ 95 range(1, max_intx) 96 97 #endif // SHARE_GC_EPSILON_EPSILON_GLOBALS_HPP