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  *

    23  */

    24 

    25 #ifndef SHARE_VM_RUNTIME_PERFDATA_HPP

    26 #define SHARE_VM_RUNTIME_PERFDATA_HPP

    27 

    28 #include "memory/allocation.inline.hpp"

    29 #include "runtime/perfMemory.hpp"

    30 #include "runtime/timer.hpp"

    31 #include "utilities/growableArray.hpp"

    32 

    33 /* jvmstat global and subsystem counter name space - enumeration value

    34  * serve as an index into the PerfDataManager::_name_space[] array

    35  * containing the corresponding name space string. Only the top level

    36  * subsystem name spaces are represented here.

    37  */

    38 enum CounterNS {

    39   // top level name spaces

    40   JAVA_NS,

    41   COM_NS,

    42   SUN_NS,

    43   // subsystem name spaces

    44   JAVA_GC,              // Garbage Collection name spaces

    45   COM_GC,

    46   SUN_GC,

    47   JAVA_CI,              // Compiler name spaces

    48   COM_CI,

    49   SUN_CI,

    50   JAVA_CLS,             // Class Loader name spaces

    51   COM_CLS,

    52   SUN_CLS,

    53   JAVA_RT,              // Runtime name spaces

    54   COM_RT,

    55   SUN_RT,

    56   JAVA_OS,              // Operating System name spaces

    57   COM_OS,

    58   SUN_OS,

    59   JAVA_THREADS,         // Threads System name spaces

    60   COM_THREADS,

    61   SUN_THREADS,

    62   JAVA_PROPERTY,        // Java Property name spaces

    63   COM_PROPERTY,

    64   SUN_PROPERTY,

    65   NULL_NS,

    66   COUNTERNS_LAST = NULL_NS

    67 };

    68 

    69 /*

    70  * Classes to support access to production performance data

    71  *

    72  * The PerfData class structure is provided for creation, access, and update

    73  * of performance data (a.k.a. instrumentation) in a specific memory region

    74  * which is possibly accessible as shared memory. Although not explicitly

    75  * prevented from doing so, developers should not use the values returned

    76  * by accessor methods to make algorithmic decisions as they are potentially

    77  * extracted from a shared memory region. Although any shared memory region

    78  * created is with appropriate access restrictions, allowing read-write access

    79  * only to the principal that created the JVM, it is believed that a the

    80  * shared memory region facilitates an easier attack path than attacks

    81  * launched through mechanisms such as /proc. For this reason, it is

    82  * recommended that data returned by PerfData accessor methods be used

    83  * cautiously.

    84  *

    85  * There are three variability classifications of performance data

    86  *   Constants  -  value is written to the PerfData memory once, on creation

    87  *   Variables  -  value is modifiable, with no particular restrictions

    88  *   Counters   -  value is monotonically changing (increasing or decreasing)

    89  *

    90  * The performance data items can also have various types. The class

    91  * hierarchy and the structure of the memory region are designed to

    92  * accommodate new types as they are needed. Types are specified in

    93  * terms of Java basic types, which accommodates client applications

    94  * written in the Java programming language. The class hierarchy is:

    95  *

    96  * - PerfData (Abstract)

    97  *     - PerfLong (Abstract)

    98  *         - PerfLongConstant        (alias: PerfConstant)

    99  *         - PerfLongVariant (Abstract)

   100  *             - PerfLongVariable    (alias: PerfVariable)

   101  *             - PerfLongCounter     (alias: PerfCounter)

   102  *

   103  *     - PerfByteArray (Abstract)

   104  *         - PerfString (Abstract)

   105  *             - PerfStringVariable

   106  *             - PerfStringConstant

   107  *

   108  *

   109  * As seen in the class hierarchy, the initially supported types are:

   110  *

   111  *    Long      - performance data holds a Java long type

   112  *    ByteArray - performance data holds an array of Java bytes

   113  *                used for holding C++ char arrays.

   114  *

   115  * The String type is derived from the ByteArray type.

   116  *

   117  * A PerfData subtype is not required to provide an implementation for

   118  * each variability classification. For example, the String type provides

   119  * Variable and Constant variability classifications in the PerfStringVariable

   120  * and PerfStringConstant classes, but does not provide a counter type.

   121  *

   122  * Performance data are also described by a unit of measure. Units allow

   123  * client applications to make reasonable decisions on how to treat

   124  * performance data generically, preventing the need to hard-code the

   125  * specifics of a particular data item in client applications. The current

   126  * set of units are:

   127  *

   128  *   None        - the data has no units of measure

   129  *   Bytes       - data is measured in bytes

   130  *   Ticks       - data is measured in clock ticks

   131  *   Events      - data is measured in events. For example,

   132  *                 the number of garbage collection events or the

   133  *                 number of methods compiled.

   134  *   String      - data is not numerical. For example,

   135  *                 the java command line options

   136  *   Hertz       - data is a frequency

   137  *

   138  * The performance counters also provide a support attribute, indicating

   139  * the stability of the counter as a programmatic interface. The support

   140  * level is also implied by the name space in which the counter is created.

   141  * The counter name space support conventions follow the Java package, class,

   142  * and property support conventions:

   143  *

   144  *    java.*          - stable, supported interface

   145  *    com.sun.*       - unstable, supported interface

   146  *    sun.*           - unstable, unsupported interface

   147  *

   148  * In the above context, unstable is a measure of the interface support

   149  * level, not the implementation stability level.

   150  *

   151  * Currently, instances of PerfData subtypes are considered to have

   152  * a life time equal to that of the VM and are managed by the

   153  * PerfDataManager class. All constructors for the PerfData class and

   154  * its subtypes have protected constructors. Creation of PerfData

   155  * instances is performed by invoking various create methods on the

   156  * PerfDataManager class. Users should not attempt to delete these

   157  * instances as the PerfDataManager class expects to perform deletion

   158  * operations on exit of the VM.

   159  *

   160  * Examples:

   161  *

   162  * Creating performance counter that holds a monotonically increasing

   163  * long data value with units specified in U_Bytes in the "java.gc.*"

   164  * name space.

   165  *

   166  *   PerfLongCounter* foo_counter;

   167  *

   168  *   foo_counter = PerfDataManager::create_long_counter(JAVA_GC, "foo",

   169  *                                                       PerfData::U_Bytes,

   170  *                                                       optionalInitialValue,

   171  *                                                       CHECK);

   172  *   foo_counter->inc();

   173  *

   174  * Creating a performance counter that holds a variably change long

   175  * data value with units specified in U_Bytes in the "com.sun.ci

   176  * name space.

   177  *

   178  *   PerfLongVariable* bar_variable;

   179  *   bar_variable = PerfDataManager::create_long_variable(COM_CI, "bar",

   180 .*                                                        PerfData::U_Bytes,

   181  *                                                        optionalInitialValue,

   182  *                                                        CHECK);

   183  *

   184  *   bar_variable->inc();

   185  *   bar_variable->set_value(0);

   186  *

   187  * Creating a performance counter that holds a constant string value in

   188  * the "sun.cls.*" name space.

   189  *

   190  *   PerfDataManager::create_string_constant(SUN_CLS, "foo", string, CHECK);

   191  *

   192  *   Although the create_string_constant() factory method returns a pointer

   193  *   to the PerfStringConstant object, it can safely be ignored. Developers

   194  *   are not encouraged to access the string constant's value via this

   195  *   pointer at this time due to security concerns.

   196  *

   197  * Creating a performance counter in an arbitrary name space that holds a

   198  * value that is sampled by the StatSampler periodic task.

   199  *

   200  *    PerfDataManager::create_counter("foo.sampled", PerfData::U_Events,

   201  *                                    &my_jlong, CHECK);

   202  *

   203  *    In this example, the PerfData pointer can be ignored as the caller

   204  *    is relying on the StatSampler PeriodicTask to sample the given

   205  *    address at a regular interval. The interval is defined by the

   206  *    PerfDataSamplingInterval global variable, and is applied on

   207  *    a system wide basis, not on an per-counter basis.

   208  *

   209  * Creating a performance counter in an arbitrary name space that utilizes

   210  * a helper object to return a value to the StatSampler via the take_sample()

   211  * method.

   212  *

   213  *     class MyTimeSampler : public PerfLongSampleHelper {

   214  *       public:

   215  *         jlong take_sample() { return os::elapsed_counter(); }

   216  *     };

   217  *

   218  *     PerfDataManager::create_counter(SUN_RT, "helped",

   219  *                                     PerfData::U_Ticks,

   220  *                                     new MyTimeSampler(), CHECK);

   221  *

   222  *     In this example, a subtype of PerfLongSampleHelper is instantiated

   223  *     and its take_sample() method is overridden to perform whatever

   224  *     operation is necessary to generate the data sample. This method

   225  *     will be called by the StatSampler at a regular interval, defined

   226  *     by the PerfDataSamplingInterval global variable.

   227  *

   228  *     As before, PerfSampleHelper is an alias for PerfLongSampleHelper.

   229  *

   230  * For additional uses of PerfData subtypes, see the utility classes

   231  * PerfTraceTime and PerfTraceTimedEvent below.

   232  *

   233  * Always-on non-sampled counters can be created independent of

   234  * the UsePerfData flag. Counters will be created on the c-heap

   235  * if UsePerfData is false.

   236  *

   237  * Until further notice, all PerfData objects should be created and

   238  * manipulated within a guarded block. The guard variable is

   239  * UsePerfData, a product flag set to true by default. This flag may

   240  * be removed from the product in the future.

   241  *

   242  */

   243 class PerfData : public CHeapObj<mtInternal> {

   244 

   245   friend class StatSampler;      // for access to protected void sample()

   246   friend class PerfDataManager;  // for access to protected destructor

   247 

   248   public:

   249 

   250     // the Variability enum must be kept in synchronization with the

   251     // the com.sun.hotspot.perfdata.Variability class

   252     enum Variability {

   253       V_Constant = 1,

   254       V_Monotonic = 2,

   255       V_Variable = 3,

   256       V_last = V_Variable

   257     };

   258 

   259     // the Units enum must be kept in synchronization with the

   260     // the com.sun.hotspot.perfdata.Units class

   261     enum Units {

   262       U_None = 1,

   263       U_Bytes = 2,

   264       U_Ticks = 3,

   265       U_Events = 4,

   266       U_String = 5,

   267       U_Hertz = 6,

   268       U_Last = U_Hertz

   269     };

   270 

   271     // Miscellaneous flags

   272     enum Flags {

   273       F_None = 0x0,

   274       F_Supported = 0x1    // interface is supported - java.* and com.sun.*

   275     };

   276 

   277   private:

   278     char* _name;

   279     Variability _v;

   280     Units _u;

   281     bool _on_c_heap;

   282     Flags _flags;

   283 

   284     PerfDataEntry* _pdep;

   285 

   286   protected:

   287 

   288     void *_valuep;

   289 

   290     PerfData(CounterNS ns, const char* name, Units u, Variability v);

   291     virtual ~PerfData();

   292 

   293     // create the entry for the PerfData item in the PerfData memory region.

   294     // this region is maintained separately from the PerfData objects to

   295     // facilitate its use by external processes.

   296     void create_entry(BasicType dtype, size_t dsize, size_t dlen = 0);

   297 

   298     // sample the data item given at creation time and write its value

   299     // into the its corresponding PerfMemory location.

   300     virtual void sample() = 0;

   301 

   302   public:

   303 

   304     // returns a boolean indicating the validity of this object.

   305     // the object is valid if and only if memory in PerfMemory

   306     // region was successfully allocated.

   307     inline bool is_valid() { return _valuep != NULL; }

   308 

   309     // returns a boolean indicating whether the underlying object

   310     // was allocated in the PerfMemory region or on the C heap.

   311     inline bool is_on_c_heap() { return _on_c_heap; }

   312 

   313     // returns a pointer to a char* containing the name of the item.

   314     // The pointer returned is the pointer to a copy of the name

   315     // passed to the constructor, not the pointer to the name in the

   316     // PerfData memory region. This redundancy is maintained for

   317     // security reasons as the PerfMemory region may be in shared

   318     // memory.

   319     const char* name() { return _name; }

   320 

   321     // returns the variability classification associated with this item

   322     Variability variability() { return _v; }

   323 

   324     // returns the units associated with this item.

   325     Units units() { return _u; }

   326 

   327     // returns the flags associated with this item.

   328     Flags flags() { return _flags; }

   329 

   330     // returns the address of the data portion of the item in the

   331     // PerfData memory region.

   332     inline void* get_address() { return _valuep; }

   333 

   334     // returns the value of the data portion of the item in the

   335     // PerfData memory region formatted as a string.

   336     virtual int format(char* cp, int length) = 0;

   337 };

   338 

   339 /*

   340  * PerfLongSampleHelper, and its alias PerfSamplerHelper, is a base class

   341  * for helper classes that rely upon the StatSampler periodic task to

   342  * invoke the take_sample() method and write the value returned to its

   343  * appropriate location in the PerfData memory region.

   344  */

   345 class PerfLongSampleHelper : public CHeapObj<mtInternal> {

   346   public:

   347     virtual jlong take_sample() = 0;

   348 };

   349 

   350 typedef PerfLongSampleHelper PerfSampleHelper;

   351 

   352 

   353 /*

   354  * PerfLong is the base class for the various Long PerfData subtypes.

   355  * it contains implementation details that are common among its derived

   356  * types.

   357  */

   358 class PerfLong : public PerfData {

   359 

   360   protected:

   361 

   362     PerfLong(CounterNS ns, const char* namep, Units u, Variability v);

   363 

   364   public:

   365     int format(char* buffer, int length);

   366 

   367     // returns the value of the data portion of the item in the

   368     // PerfData memory region.

   369     inline jlong get_value() { return *(jlong*)_valuep; }

   370 };

   371 

   372 /*

   373  * The PerfLongConstant class, and its alias PerfConstant, implement

   374  * a PerfData subtype that holds a jlong data value that is set upon

   375  * creation of an instance of this class. This class provides no

   376  * methods for changing the data value stored in PerfData memory region.

   377  */

   378 class PerfLongConstant : public PerfLong {

   379 

   380   friend class PerfDataManager; // for access to protected constructor

   381 

   382   private:

   383     // hide sample() - no need to sample constants

   384     void sample() { }

   385 

   386   protected:

   387 

   388     PerfLongConstant(CounterNS ns, const char* namep, Units u,

   389                      jlong initial_value=0)

   390                     : PerfLong(ns, namep, u, V_Constant) {

   391 

   392        if (is_valid()) *(jlong*)_valuep = initial_value;

   393     }

   394 };

   395 

   396 typedef PerfLongConstant PerfConstant;

   397 

   398 /*

   399  * The PerfLongVariant class, and its alias PerfVariant, implement

   400  * a PerfData subtype that holds a jlong data value that can be modified

   401  * in an unrestricted manner. This class provides the implementation details

   402  * for common functionality among its derived types.

   403  */

   404 class PerfLongVariant : public PerfLong {

   405 

   406   protected:

   407     jlong* _sampled;

   408     PerfLongSampleHelper* _sample_helper;

   409 

   410     PerfLongVariant(CounterNS ns, const char* namep, Units u, Variability v,

   411                     jlong initial_value=0)

   412                    : PerfLong(ns, namep, u, v) {

   413       if (is_valid()) *(jlong*)_valuep = initial_value;

   414     }

   415 

   416     PerfLongVariant(CounterNS ns, const char* namep, Units u, Variability v,

   417                     jlong* sampled);

   418 

   419     PerfLongVariant(CounterNS ns, const char* namep, Units u, Variability v,

   420                     PerfLongSampleHelper* sample_helper);

   421 

   422     void sample();

   423 

   424   public:

   425     inline void inc() { (*(jlong*)_valuep)++; }

   426     inline void inc(jlong val) { (*(jlong*)_valuep) += val; }

   427     inline void dec(jlong val) { inc(-val); }

   428     inline void add(jlong val) { (*(jlong*)_valuep) += val; }

   429     void clear_sample_helper() { _sample_helper = NULL; }

   430 };

   431 

   432 /*

   433  * The PerfLongCounter class, and its alias PerfCounter, implement

   434  * a PerfData subtype that holds a jlong data value that can (should)

   435  * be modified in a monotonic manner. The inc(jlong) and add(jlong)

   436  * methods can be passed negative values to implement a monotonically

   437  * decreasing value. However, we rely upon the programmer to honor

   438  * the notion that this counter always moves in the same direction -

   439  * either increasing or decreasing.

   440  */

   441 class PerfLongCounter : public PerfLongVariant {

   442 

   443   friend class PerfDataManager; // for access to protected constructor

   444 

   445   protected:

   446 

   447     PerfLongCounter(CounterNS ns, const char* namep, Units u,

   448                     jlong initial_value=0)

   449                    : PerfLongVariant(ns, namep, u, V_Monotonic,

   450                                      initial_value) { }

   451 

   452     PerfLongCounter(CounterNS ns, const char* namep, Units u, jlong* sampled)

   453                   : PerfLongVariant(ns, namep, u, V_Monotonic, sampled) { }

   454 

   455     PerfLongCounter(CounterNS ns, const char* namep, Units u,

   456                     PerfLongSampleHelper* sample_helper)

   457                    : PerfLongVariant(ns, namep, u, V_Monotonic,

   458                                      sample_helper) { }

   459 };

   460 

   461 typedef PerfLongCounter PerfCounter;

   462 

   463 /*

   464  * The PerfLongVariable class, and its alias PerfVariable, implement

   465  * a PerfData subtype that holds a jlong data value that can

   466  * be modified in an unrestricted manner.

   467  */

   468 class PerfLongVariable : public PerfLongVariant {

   469 

   470   friend class PerfDataManager; // for access to protected constructor

   471 

   472   protected:

   473 

   474     PerfLongVariable(CounterNS ns, const char* namep, Units u,

   475                      jlong initial_value=0)

   476                     : PerfLongVariant(ns, namep, u, V_Variable,

   477                                       initial_value) { }

   478 

   479     PerfLongVariable(CounterNS ns, const char* namep, Units u, jlong* sampled)

   480                     : PerfLongVariant(ns, namep, u, V_Variable, sampled) { }

   481 

   482     PerfLongVariable(CounterNS ns, const char* namep, Units u,

   483                      PerfLongSampleHelper* sample_helper)

   484                     : PerfLongVariant(ns, namep, u, V_Variable,

   485                                       sample_helper) { }

   486 

   487   public:

   488     inline void set_value(jlong val) { (*(jlong*)_valuep) = val; }

   489 };

   490 

   491 typedef PerfLongVariable PerfVariable;

   492 

   493 /*

   494  * The PerfByteArray provides a PerfData subtype that allows the creation

   495  * of a contiguous region of the PerfData memory region for storing a vector

   496  * of bytes. This class is currently intended to be a base class for

   497  * the PerfString class, and cannot be instantiated directly.

   498  */

   499 class PerfByteArray : public PerfData {

   500 

   501   protected:

   502     jint _length;

   503 

   504     PerfByteArray(CounterNS ns, const char* namep, Units u, Variability v,

   505                   jint length);

   506 };

   507 

   508 class PerfString : public PerfByteArray {

   509 

   510   protected:

   511 

   512     void set_string(const char* s2);

   513 

   514     PerfString(CounterNS ns, const char* namep, Variability v, jint length,

   515                const char* initial_value)

   516               : PerfByteArray(ns, namep, U_String, v, length) {

   517        if (is_valid()) set_string(initial_value);

   518     }

   519 

   520   public:

   521 

   522     int format(char* buffer, int length);

   523 };

   524 

   525 /*

   526  * The PerfStringConstant class provides a PerfData sub class that

   527  * allows a null terminated string of single byte characters to be

   528  * stored in the PerfData memory region.

   529  */

   530 class PerfStringConstant : public PerfString {

   531 

   532   friend class PerfDataManager; // for access to protected constructor

   533 

   534   private:

   535 

   536     // hide sample() - no need to sample constants

   537     void sample() { }

   538 

   539   protected:

   540 

   541     // Restrict string constant lengths to be <= PerfMaxStringConstLength.

   542     // This prevents long string constants, as can occur with very

   543     // long classpaths or java command lines, from consuming too much

   544     // PerfData memory.

   545     PerfStringConstant(CounterNS ns, const char* namep,

   546                        const char* initial_value);

   547 };

   548 

   549 /*

   550  * The PerfStringVariable class provides a PerfData sub class that

   551  * allows a null terminated string of single byte character data

   552  * to be stored in PerfData memory region. The string value can be reset

   553  * after initialization. If the string value is >= max_length, then

   554  * it will be truncated to max_length characters. The copied string

   555  * is always null terminated.

   556  */

   557 class PerfStringVariable : public PerfString {

   558 

   559   friend class PerfDataManager; // for access to protected constructor

   560 

   561   protected:

   562 

   563     // sampling of string variables are not yet supported

   564     void sample() { }

   565 

   566     PerfStringVariable(CounterNS ns, const char* namep, jint max_length,

   567                        const char* initial_value)

   568                       : PerfString(ns, namep, V_Variable, max_length+1,

   569                                    initial_value) { }

   570 

   571   public:

   572     inline void set_value(const char* val) { set_string(val); }

   573 };

   574 

   575 

   576 /*

   577  * The PerfDataList class is a container class for managing lists

   578  * of PerfData items. The intention of this class is to allow for

   579  * alternative implementations for management of list of PerfData

   580  * items without impacting the code that uses the lists.

   581  *

   582  * The initial implementation is based upon GrowableArray. Searches

   583  * on GrowableArray types is linear in nature and this may become

   584  * a performance issue for creation of PerfData items, particularly

   585  * from Java code where a test for existence is implemented as a

   586  * search over all existing PerfData items.

   587  *

   588  * The abstraction is not complete. A more general container class

   589  * would provide an Iterator abstraction that could be used to

   590  * traverse the lists. This implementation still relies upon integer

   591  * iterators and the at(int index) method. However, the GrowableArray

   592  * is not directly visible outside this class and can be replaced by

   593  * some other implementation, as long as that implementation provides

   594  * a mechanism to iterate over the container by index.

   595  */

   596 class PerfDataList : public CHeapObj<mtInternal> {

   597 

   598   private:

   599 

   600     // GrowableArray implementation

   601     typedef GrowableArray<PerfData*> PerfDataArray;

   602 

   603     PerfDataArray* _set;

   604 

   605     // method to search for a instrumentation object by name

   606     static bool by_name(void* name, PerfData* pd);

   607 

   608   protected:

   609     // we expose the implementation here to facilitate the clone

   610     // method.

   611     PerfDataArray* get_impl() { return _set; }

   612 

   613   public:

   614 

   615     // create a PerfDataList with the given initial length

   616     PerfDataList(int length);

   617 

   618     // create a PerfDataList as a shallow copy of the given PerfDataList

   619     PerfDataList(PerfDataList* p);

   620 

   621     ~PerfDataList();

   622 

   623     // return the PerfData item indicated by name,

   624     // or NULL if it doesn't exist.

   625     PerfData* find_by_name(const char* name);

   626 

   627     // return true if a PerfData item with the name specified in the

   628     // argument exists, otherwise return false.

   629     bool contains(const char* name) { return find_by_name(name) != NULL; }

   630 

   631     // return the number of PerfData items in this list

   632     int length() { return _set->length(); }

   633 

   634     // add a PerfData item to this list

   635     void append(PerfData *p) { _set->append(p); }

   636 

   637     // remove the given PerfData item from this list. When called

   638     // while iterating over the list, this method will result in a

   639     // change in the length of the container. The at(int index)

   640     // method is also impacted by this method as elements with an

   641     // index greater than the index of the element removed by this

   642     // method will be shifted down by one.

   643     void remove(PerfData *p) { _set->remove(p); }

   644 

   645     // create a new PerfDataList from this list. The new list is

   646     // a shallow copy of the original list and care should be taken

   647     // with respect to delete operations on the elements of the list

   648     // as the are likely in use by another copy of the list.

   649     PerfDataList* clone();

   650 

   651     // for backward compatibility with GrowableArray - need to implement

   652     // some form of iterator to provide a cleaner abstraction for

   653     // iteration over the container.

   654     PerfData* at(int index) { return _set->at(index); }

   655 };

   656 

   657 

   658 /*

   659  * The PerfDataManager class is responsible for creating PerfData

   660  * subtypes via a set a factory methods and for managing lists

   661  * of the various PerfData types.

   662  */

   663 class PerfDataManager : AllStatic {

   664 

   665   friend class StatSampler;   // for access to protected PerfDataList methods

   666 

   667   private:

   668     static PerfDataList* _all;

   669     static PerfDataList* _sampled;

   670     static PerfDataList* _constants;

   671     static const char* _name_spaces[];

   672     static volatile bool _has_PerfData;

   673 

   674     // add a PerfData item to the list(s) of know PerfData objects

   675     static void add_item(PerfData* p, bool sampled);

   676 

   677   protected:

   678     // return the list of all known PerfData items

   679     static PerfDataList* all();

   680     static int count() { return _all->length(); }

   681 

   682     // return the list of all known PerfData items that are to be

   683     // sampled by the StatSampler.

   684     static PerfDataList* sampled();

   685     static int sampled_count() { return _sampled->length(); }

   686 

   687     // return the list of all known PerfData items that have a

   688     // variability classification of type Constant

   689     static PerfDataList* constants();

   690     static int constants_count() { return _constants->length(); }

   691 

   692   public:

   693 

   694     // method to check for the existence of a PerfData item with

   695     // the given name.

   696     static bool exists(const char* name) { return _all->contains(name); }

   697 

   698     // method to search for a instrumentation object by name

   699     static PerfData* find_by_name(const char* name);

   700 

   701     // method to map a CounterNS enumeration to a namespace string

   702     static const char* ns_to_string(CounterNS ns) {

   703       return _name_spaces[ns];

   704     }

   705 

   706     // methods to test the interface stability of a given counter namespace

   707     //

   708     static bool is_stable_supported(CounterNS ns) {

   709       return (ns != NULL_NS) && ((ns % 3) == JAVA_NS);

   710     }

   711     static bool is_unstable_supported(CounterNS ns) {

   712       return (ns != NULL_NS) && ((ns % 3) == COM_NS);

   713     }

   714     static bool is_unstable_unsupported(CounterNS ns) {

   715       return (ns == NULL_NS) || ((ns % 3) == SUN_NS);

   716     }

   717 

   718     // methods to test the interface stability of a given counter name

   719     //

   720     static bool is_stable_supported(const char* name) {

   721       const char* javadot = "java.";

   722       return strncmp(name, javadot, strlen(javadot)) == 0;

   723     }

   724     static bool is_unstable_supported(const char* name) {

   725       const char* comdot = "com.sun.";

   726       return strncmp(name, comdot, strlen(comdot)) == 0;

   727     }

   728     static bool is_unstable_unsupported(const char* name) {

   729       return !(is_stable_supported(name) && is_unstable_supported(name));

   730     }

   731 

   732     // method to construct counter name strings in a given name space.

   733     // The string object is allocated from the Resource Area and calls

   734     // to this method must be made within a ResourceMark.

   735     //

   736     static char* counter_name(const char* name_space, const char* name);

   737 

   738     // method to construct name space strings in a given name space.

   739     // The string object is allocated from the Resource Area and calls

   740     // to this method must be made within a ResourceMark.

   741     //

   742     static char* name_space(const char* name_space, const char* sub_space) {

   743       return counter_name(name_space, sub_space);

   744     }

   745 

   746     // same as above, but appends the instance number to the name space

   747     //

   748     static char* name_space(const char* name_space, const char* sub_space,

   749                             int instance);

   750     static char* name_space(const char* name_space, int instance);

   751 

   752 

   753     // these methods provide the general interface for creating

   754     // performance data resources. The types of performance data

   755     // resources can be extended by adding additional create<type>

   756     // methods.

   757 

   758     // Constant Types

   759     static PerfStringConstant* create_string_constant(CounterNS ns,

   760                                                       const char* name,

   761                                                       const char *s, TRAPS);

   762 

   763     static PerfLongConstant* create_long_constant(CounterNS ns,

   764                                                   const char* name,

   765                                                   PerfData::Units u,

   766                                                   jlong val, TRAPS);

   767 

   768 

   769     // Variable Types

   770     static PerfStringVariable* create_string_variable(CounterNS ns,

   771                                                       const char* name,

   772                                                       int max_length,

   773                                                       const char *s, TRAPS);

   774 

   775     static PerfStringVariable* create_string_variable(CounterNS ns,

   776                                                       const char* name,

   777                                                       const char *s, TRAPS) {

   778       return create_string_variable(ns, name, 0, s, THREAD);

   779     };

   780 

   781     static PerfLongVariable* create_long_variable(CounterNS ns,

   782                                                   const char* name,

   783                                                   PerfData::Units u,

   784                                                   jlong ival, TRAPS);

   785 

   786     static PerfLongVariable* create_long_variable(CounterNS ns,

   787                                                   const char* name,

   788                                                   PerfData::Units u, TRAPS) {

   789       return create_long_variable(ns, name, u, (jlong)0, THREAD);

   790     };

   791 

   792     static PerfLongVariable* create_long_variable(CounterNS, const char* name,

   793                                                   PerfData::Units u,

   794                                                   jlong* sp, TRAPS);

   795 

   796     static PerfLongVariable* create_long_variable(CounterNS ns,

   797                                                   const char* name,

   798                                                   PerfData::Units u,

   799                                                   PerfLongSampleHelper* sh,

   800                                                   TRAPS);

   801 

   802 

   803     // Counter Types

   804     static PerfLongCounter* create_long_counter(CounterNS ns, const char* name,

   805                                                 PerfData::Units u,

   806                                                 jlong ival, TRAPS);

   807 

   808     static PerfLongCounter* create_long_counter(CounterNS ns, const char* name,

   809                                                 PerfData::Units u, TRAPS) {

   810       return create_long_counter(ns, name, u, (jlong)0, THREAD);

   811     };

   812 

   813     static PerfLongCounter* create_long_counter(CounterNS ns, const char* name,

   814                                                 PerfData::Units u, jlong* sp,

   815                                                 TRAPS);

   816 

   817     static PerfLongCounter* create_long_counter(CounterNS ns, const char* name,

   818                                                 PerfData::Units u,

   819                                                 PerfLongSampleHelper* sh,

   820                                                 TRAPS);

   821 

   822 

   823     // these creation methods are provided for ease of use. These allow

   824     // Long performance data types to be created with a shorthand syntax.

   825 

   826     static PerfConstant* create_constant(CounterNS ns, const char* name,

   827                                          PerfData::Units u, jlong val, TRAPS) {

   828       return create_long_constant(ns, name, u, val, THREAD);

   829     }

   830 

   831     static PerfVariable* create_variable(CounterNS ns, const char* name,

   832                                          PerfData::Units u, jlong ival, TRAPS) {

   833       return create_long_variable(ns, name, u, ival, THREAD);

   834     }

   835 

   836     static PerfVariable* create_variable(CounterNS ns, const char* name,

   837                                          PerfData::Units u, TRAPS) {

   838       return create_long_variable(ns, name, u, (jlong)0, THREAD);

   839     }

   840 

   841     static PerfVariable* create_variable(CounterNS ns, const char* name,

   842                                          PerfData::Units u, jlong* sp, TRAPS) {

   843       return create_long_variable(ns, name, u, sp, THREAD);

   844     }

   845 

   846     static PerfVariable* create_variable(CounterNS ns, const char* name,

   847                                          PerfData::Units u,

   848                                          PerfSampleHelper* sh, TRAPS) {

   849       return create_long_variable(ns, name, u, sh, THREAD);

   850     }

   851 

   852     static PerfCounter* create_counter(CounterNS ns, const char* name,

   853                                        PerfData::Units u, jlong ival, TRAPS) {

   854       return create_long_counter(ns, name, u, ival, THREAD);

   855     }

   856 

   857     static PerfCounter* create_counter(CounterNS ns, const char* name,

   858                                        PerfData::Units u, TRAPS) {

   859       return create_long_counter(ns, name, u, (jlong)0, THREAD);

   860     }

   861 

   862     static PerfCounter* create_counter(CounterNS ns, const char* name,

   863                                        PerfData::Units u, jlong* sp, TRAPS) {

   864       return create_long_counter(ns, name, u, sp, THREAD);

   865     }

   866 

   867     static PerfCounter* create_counter(CounterNS ns, const char* name,

   868                                        PerfData::Units u,

   869                                        PerfSampleHelper* sh, TRAPS) {

   870       return create_long_counter(ns, name, u, sh, THREAD);

   871     }

   872 

   873     static void destroy();

   874     static bool has_PerfData() { return _has_PerfData; }

   875 };

   876 

   877 // Useful macros to create the performance counters

   878 #define NEWPERFTICKCOUNTER(counter, counter_ns, counter_name)  \

   879   {counter = PerfDataManager::create_counter(counter_ns, counter_name, \

   880                                              PerfData::U_Ticks,CHECK);}

   881 

   882 #define NEWPERFEVENTCOUNTER(counter, counter_ns, counter_name)  \

   883   {counter = PerfDataManager::create_counter(counter_ns, counter_name, \

   884                                              PerfData::U_Events,CHECK);}

   885 

   886 #define NEWPERFBYTECOUNTER(counter, counter_ns, counter_name)  \

   887   {counter = PerfDataManager::create_counter(counter_ns, counter_name, \

   888                                              PerfData::U_Bytes,CHECK);}

   889 

   890 // Utility Classes

   891 

   892 /*

   893  * this class will administer a PerfCounter used as a time accumulator

   894  * for a basic block much like the TraceTime class.

   895  *

   896  * Example:

   897  *

   898  *    static PerfCounter* my_time_counter = PerfDataManager::create_counter("my.time.counter", PerfData::U_Ticks, 0LL, CHECK);

   899  *

   900  *    {

   901  *      PerfTraceTime ptt(my_time_counter);

   902  *      // perform the operation you want to measure

   903  *    }

   904  *

   905  * Note: use of this class does not need to occur within a guarded

   906  * block. The UsePerfData guard is used with the implementation

   907  * of this class.

   908  */

   909 class PerfTraceTime : public StackObj {

   910 

   911   protected:

   912     elapsedTimer _t;

   913     PerfLongCounter* _timerp;

   914     // pointer to thread-local or global recursion counter variable

   915     int* _recursion_counter;

   916 

   917   public:

   918     inline PerfTraceTime(PerfLongCounter* timerp) : _timerp(timerp), _recursion_counter(NULL) {

   919       if (!UsePerfData) return;

   920       _t.start();

   921     }

   922 

   923     inline PerfTraceTime(PerfLongCounter* timerp, int* recursion_counter) : _timerp(timerp), _recursion_counter(recursion_counter) {

   924       if (!UsePerfData || (_recursion_counter != NULL &&

   925                            (*_recursion_counter)++ > 0)) return;

   926       _t.start();

   927     }

   928 

   929     inline void suspend() { if (!UsePerfData) return; _t.stop(); }

   930     inline void resume() { if (!UsePerfData) return; _t.start(); }

   931 

   932     inline ~PerfTraceTime() {

   933       if (!UsePerfData || (_recursion_counter != NULL &&

   934                            --(*_recursion_counter) > 0)) return;

   935       _t.stop();

   936       _timerp->inc(_t.ticks());

   937     }

   938 };

   939 

   940 /* The PerfTraceTimedEvent class is responsible for counting the

   941  * occurrence of some event and measuring the the elapsed time of

   942  * the event in two separate PerfCounter instances.

   943  *

   944  * Example:

   945  *

   946  *    static PerfCounter* my_time_counter = PerfDataManager::create_counter("my.time.counter", PerfData::U_Ticks, CHECK);

   947  *    static PerfCounter* my_event_counter = PerfDataManager::create_counter("my.event.counter", PerfData::U_Events, CHECK);

   948  *

   949  *    {

   950  *      PerfTraceTimedEvent ptte(my_time_counter, my_event_counter);

   951  *      // perform the operation you want to count and measure

   952  *    }

   953  *

   954  * Note: use of this class does not need to occur within a guarded

   955  * block. The UsePerfData guard is used with the implementation

   956  * of this class.

   957  *

   958  */

   959 class PerfTraceTimedEvent : public PerfTraceTime {

   960 

   961   protected:

   962     PerfLongCounter* _eventp;

   963 

   964   public:

   965     inline PerfTraceTimedEvent(PerfLongCounter* timerp, PerfLongCounter* eventp): PerfTraceTime(timerp), _eventp(eventp) {

   966       if (!UsePerfData) return;

   967       _eventp->inc();

   968     }

   969 

   970     inline PerfTraceTimedEvent(PerfLongCounter* timerp, PerfLongCounter* eventp, int* recursion_counter): PerfTraceTime(timerp, recursion_counter), _eventp(eventp) {

   971       if (!UsePerfData) return;

   972       _eventp->inc();

   973     }

   974 };

   975 

   976 #endif // SHARE_VM_RUNTIME_PERFDATA_HPP