1/*
2 * Copyright (c) 1998, 2014, 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_UTILITIES_HISTOGRAM_HPP
26#define SHARE_VM_UTILITIES_HISTOGRAM_HPP
27
28#include "memory/allocation.hpp"
29#include "runtime/os.hpp"
30#include "utilities/growableArray.hpp"
31
32// This class provides a framework for collecting various statistics.
33// The current implementation is oriented towards counting invocations
34// of various types, but that can be easily changed.
35//
36// To use it, you need to declare a Histogram*, and a subtype of
37// HistogramElement:
38//
39//  HistogramElement* MyHistogram;
40//
41//  class MyHistogramElement : public HistogramElement {
42//    public:
43//      MyHistogramElement(char* name);
44//  };
45//
46//  MyHistogramElement::MyHistogramElement(char* elementName) {
47//    _name = elementName;
48//
49//    if(MyHistogram == NULL)
50//      MyHistogram = new Histogram("My Call Counts",100);
51//
52//    MyHistogram->add_element(this);
53//  }
54//
55//  #define MyCountWrapper(arg) static MyHistogramElement* e = new MyHistogramElement(arg); e->increment_count()
56//
57// This gives you a simple way to count invocations of specfic functions:
58//
59// void a_function_that_is_being_counted() {
60//   MyCountWrapper("FunctionName");
61//   ...
62// }
63//
64// To print the results, invoke print() on your Histogram*.
65
66#ifdef ASSERT
67
68class HistogramElement : public CHeapObj<mtInternal> {
69 protected:
70  jint _count;
71  const char* _name;
72
73 public:
74  HistogramElement();
75  virtual int count();
76  virtual const char* name();
77  virtual void increment_count();
78  void print_on(outputStream* st) const;
79  virtual int compare(HistogramElement* e1,HistogramElement* e2);
80};
81
82class Histogram : public CHeapObj<mtInternal> {
83 protected:
84  GrowableArray<HistogramElement*>* _elements;
85  GrowableArray<HistogramElement*>* elements() { return _elements; }
86  const char* _title;
87  const char* title() { return _title; }
88  static int sort_helper(HistogramElement** e1,HistogramElement** e2);
89  virtual void print_header(outputStream* st);
90  virtual void print_elements(outputStream* st);
91
92 public:
93  Histogram(const char* title,int estimatedSize);
94  virtual void add_element(HistogramElement* element);
95  void print_on(outputStream* st) const;
96};
97
98#endif
99
100#endif // SHARE_VM_UTILITIES_HISTOGRAM_HPP
101