1 /*
   2  * Copyright (c) 2001, 2010, 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  *
  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_STATSAMPLER_HPP
  26 #define SHARE_VM_RUNTIME_STATSAMPLER_HPP
  27 
  28 #include "runtime/perfData.hpp"
  29 #include "runtime/task.hpp"
  30 
  31 class StatSamplerTask;
  32 
  33 /*
  34  * The StatSampler class is responsible for periodically updating
  35  * sampled PerfData instances and writing the sampled values to the
  36  * PerfData memory region.
  37  *
  38  * In addition it is also responsible for providing a home for
  39  * PerfData instances that otherwise have no better home.
  40  */
  41 class StatSampler : AllStatic {
  42 
  43   friend class StatSamplerTask;
  44 
  45   private:
  46 
  47     static StatSamplerTask* _task;
  48     static PerfDataList* _sampled;
  49 
  50     static void collect_sample();
  51     static void create_misc_perfdata();
  52     static void create_sampled_perfdata();
  53     static void sample_data(PerfDataList* list);
  54     static const char* get_system_property(const char* name, TRAPS);
  55     static void create_system_property_instrumentation(TRAPS);
  56 
  57   public:
  58     // Start/stop the sampler
  59     static void engage();
  60     static void disengage();
  61 
  62     static bool is_active() { return _task != NULL; }
  63 
  64     static void initialize();
  65     static void destroy();
  66 };
  67 
  68 void statSampler_exit();
  69 
  70 #endif // SHARE_VM_RUNTIME_STATSAMPLER_HPP