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 

    68 class 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 

    82 class 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