| /* |
| * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_GC_G1_G1YOUNGREMSETSAMPLINGTHREAD_HPP |
| #define SHARE_VM_GC_G1_G1YOUNGREMSETSAMPLINGTHREAD_HPP |
| |
| #include "gc/shared/concurrentGCThread.hpp" |
| |
| // The G1YoungRemSetSamplingThread is used to re-assess the validity of |
| // the prediction for the remembered set lengths of the young generation. |
| // |
| // At the end of the GC G1 determines the length of the young gen based on |
| // how much time the next GC can take, and when the next GC may occur |
| // according to the MMU. |
| // |
| // The assumption is that a significant part of the GC is spent on scanning |
| // the remembered sets (and many other components), so this thread constantly |
| // reevaluates the prediction for the remembered set scanning costs, and potentially |
| // G1Policy resizes the young gen. This may do a premature GC or even |
| // increase the young gen size to keep pause time length goal. |
| class G1YoungRemSetSamplingThread: public ConcurrentGCThread { |
| private: |
| Monitor _monitor; |
| |
| void sample_young_list_rs_lengths(); |
| |
| void run_service(); |
| void stop_service(); |
| |
| void sleep_before_next_cycle(); |
| |
| double _vtime_accum; // Accumulated virtual time. |
| |
| public: |
| G1YoungRemSetSamplingThread(); |
| double vtime_accum() { return _vtime_accum; } |
| }; |
| |
| #endif // SHARE_VM_GC_G1_G1YOUNGREMSETSAMPLINGTHREAD_HPP |