1 /*
2 * Copyright (c) 2001, 2016, 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 *
137 // Calculates plab size for current number of gc worker threads.
138 size_t PLABStats::desired_plab_sz(uint no_of_gc_workers) {
139 return (size_t)align_object_size(MIN2(MAX2(min_size(), _desired_net_plab_sz / no_of_gc_workers), max_size()));
140 }
141
142 // Compute desired plab size for one gc worker thread and latch result for later
143 // use. This should be called once at the end of parallel
144 // scavenge; it clears the sensor accumulators.
145 void PLABStats::adjust_desired_plab_sz() {
146 log_plab_allocation();
147
148 if (!ResizePLAB) {
149 // Clear accumulators for next round.
150 reset();
151 return;
152 }
153
154 assert(is_object_aligned(max_size()) && min_size() <= max_size(),
155 "PLAB clipping computation may be incorrect");
156
157 if (_allocated == 0) {
158 assert(_unused == 0,
159 "Inconsistency in PLAB stats: "
160 "_allocated: " SIZE_FORMAT ", "
161 "_wasted: " SIZE_FORMAT ", "
162 "_unused: " SIZE_FORMAT ", "
163 "_undo_wasted: " SIZE_FORMAT,
164 _allocated, _wasted, _unused, _undo_wasted);
165
166 _allocated = 1;
167 }
168 double wasted_frac = (double)_unused / (double)_allocated;
169 size_t target_refills = (size_t)((wasted_frac * TargetSurvivorRatio) / TargetPLABWastePct);
170 if (target_refills == 0) {
171 target_refills = 1;
172 }
173 size_t used = _allocated - _wasted - _unused;
174 // Assumed to have 1 gc worker thread
175 size_t recent_plab_sz = used / target_refills;
176 // Take historical weighted average
177 _filter.sample(recent_plab_sz);
178 _desired_net_plab_sz = MAX2(min_size(), (size_t)_filter.average());
179
180 log_sizing(recent_plab_sz, _desired_net_plab_sz);
181
182 reset();
183 }
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1 /*
2 * Copyright (c) 2001, 2017, 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 *
137 // Calculates plab size for current number of gc worker threads.
138 size_t PLABStats::desired_plab_sz(uint no_of_gc_workers) {
139 return (size_t)align_object_size(MIN2(MAX2(min_size(), _desired_net_plab_sz / no_of_gc_workers), max_size()));
140 }
141
142 // Compute desired plab size for one gc worker thread and latch result for later
143 // use. This should be called once at the end of parallel
144 // scavenge; it clears the sensor accumulators.
145 void PLABStats::adjust_desired_plab_sz() {
146 log_plab_allocation();
147
148 if (!ResizePLAB) {
149 // Clear accumulators for next round.
150 reset();
151 return;
152 }
153
154 assert(is_object_aligned(max_size()) && min_size() <= max_size(),
155 "PLAB clipping computation may be incorrect");
156
157 assert(_allocated != 0 || _unused == 0,
158 "Inconsistency in PLAB stats: "
159 "_allocated: " SIZE_FORMAT ", "
160 "_wasted: " SIZE_FORMAT ", "
161 "_unused: " SIZE_FORMAT ", "
162 "_undo_wasted: " SIZE_FORMAT,
163 _allocated, _wasted, _unused, _undo_wasted);
164
165 size_t plab_sz = compute_desired_plab_sz();
166 // Take historical weighted average
167 _filter.sample(plab_sz);
168 _desired_net_plab_sz = MAX2(min_size(), (size_t)_filter.average());
169
170 log_sizing(plab_sz, _desired_net_plab_sz);
171 // Clear accumulators for next round
172 reset();
173 }
174
175 size_t PLABStats::compute_desired_plab_sz() {
176 size_t allocated = MAX2(_allocated, size_t(1));
177 double wasted_frac = (double)_unused / (double)allocated;
178 size_t target_refills = (size_t)((wasted_frac * TargetSurvivorRatio) / TargetPLABWastePct);
179 if (target_refills == 0) {
180 target_refills = 1;
181 }
182 size_t used = allocated - _wasted - _unused;
183 // Assumed to have 1 gc worker thread
184 size_t recent_plab_sz = used / target_refills;
185 return recent_plab_sz;
186 }
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