/*

 * Copyright (c) 2001, 2017, 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.

 *

 */

#include "precompiled.hpp"

#include "classfile/systemDictionary.hpp"

#include "classfile/vmSymbols.hpp"

#include "memory/allocation.inline.hpp"

#include "memory/resourceArea.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/arguments.hpp"

#include "runtime/java.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/os.hpp"

#include "runtime/perfData.inline.hpp"

#include "runtime/statSampler.hpp"

#include "runtime/vm_version.hpp"

// --------------------------------------------------------

// StatSamplerTask

class StatSamplerTask : public PeriodicTask {

  public:

    StatSamplerTask(int interval_time) : PeriodicTask(interval_time) {}

    void task() { StatSampler::collect_sample(); }

};

//----------------------------------------------------------

// Implementation of StatSampler

StatSamplerTask*              StatSampler::_task   = NULL;

PerfDataList*                 StatSampler::_sampled = NULL;

/*

 * the initialize method is called from the engage() method

 * and is responsible for initializing various global variables.

 */

void StatSampler::initialize() {

  if (!UsePerfData) return;

  // create performance data that could not be created prior

  // to vm_init_globals() or otherwise have no logical home.

  create_misc_perfdata();

  // get copy of the sampled list

  _sampled = PerfDataManager::sampled();

}

/*

 * The engage() method is called at initialization time via

 * Thread::create_vm() to initialize the StatSampler and

 * register it with the WatcherThread as a periodic task.

 */

void StatSampler::engage() {

  if (!UsePerfData) return;

  if (!is_active()) {

    initialize();

    // start up the periodic task

    _task = new StatSamplerTask(PerfDataSamplingInterval);

    _task->enroll();

  }

}

/*

 * the disengage() method is responsible for deactivating the periodic

 * task and, if logging was enabled, for logging the final sample. This

 * method is called from before_exit() in java.cpp and is only called

 * after the WatcherThread has been stopped.

 */

void StatSampler::disengage() {

  if (!UsePerfData) return;

  if (!is_active())

    return;

  // remove StatSamplerTask

  _task->disenroll();

  delete _task;

  _task = NULL;

  // force a final sample

  sample_data(_sampled);

}

/*

 * the destroy method is responsible for releasing any resources used by

 * the StatSampler prior to shutdown of the VM. this method is called from

 * before_exit() in java.cpp and is only called after the WatcherThread

 * has stopped.

 */

void StatSampler::destroy() {

  if (!UsePerfData) return;

  if (_sampled != NULL) {

    delete(_sampled);

    _sampled = NULL;

  }

}

/*

 * The sample_data() method is responsible for sampling the

 * the data value for each PerfData instance in the given list.

 */

void StatSampler::sample_data(PerfDataList* list) {

  assert(list != NULL, "null list unexpected");

  for (int index = 0; index < list->length(); index++) {

    PerfData* item = list->at(index);

    item->sample();

  }

}

/*

 * the collect_sample() method is the method invoked by the

 * WatcherThread via the PeriodicTask::task() method. This method

 * is responsible for collecting data samples from sampled

 * PerfData instances every PerfDataSamplingInterval milliseconds.

 * It is also responsible for logging the requested set of

 * PerfData instances every _sample_count milliseconds. While

 * logging data, it will output a column header after every _print_header

 * rows of data have been logged.

 */

void StatSampler::collect_sample() {

  // future - check for new PerfData objects. PerfData objects might

  // get added to the PerfDataManager lists after we have already

  // built our local copies.

  //

  // if (PerfDataManager::count() > previous) {

  //   // get a new copy of the sampled list

  //   if (_sampled != NULL) {

  //     delete(_sampled);

  //     _sampled = NULL;

  //   }

  //   _sampled = PerfDataManager::sampled();

  // }

  assert(_sampled != NULL, "list not initialized");

  sample_data(_sampled);

}

/*

 * method to upcall into Java to return the value of the specified

 * property as a utf8 string, or NULL if does not exist. The caller

 * is responsible for setting a ResourceMark for proper cleanup of

 * the utf8 strings.

 */

const char* StatSampler::get_system_property(const char* name, TRAPS) {

  // setup the arguments to getProperty

  Handle key_str   = java_lang_String::create_from_str(name, CHECK_NULL);

  // return value

  JavaValue result(T_OBJECT);

  // public static String getProperty(String key, String def);

  JavaCalls::call_static(&result,

                         SystemDictionary::System_klass(),

                         vmSymbols::getProperty_name(),

                         vmSymbols::string_string_signature(),

                         key_str,

                         CHECK_NULL);

  oop value_oop = (oop)result.get_jobject();

  if (value_oop == NULL) {

    return NULL;

  }

  // convert Java String to utf8 string

  char* value = java_lang_String::as_utf8_string(value_oop);

  return value;

}

/*

 * The list of System Properties that have corresponding PerfData

 * string instrumentation created by retrieving the named property's

 * value from System.getProperty() and unconditionally creating a

 * PerfStringConstant object initialized to the retrieved value. This

 * is not an exhaustive list of Java properties with corresponding string

 * instrumentation as the create_system_property_instrumentation() method

 * creates other property based instrumentation conditionally.

 */

// stable interface, supported counters

static const char* property_counters_ss[] = {

  "java.vm.specification.version",

  "java.vm.specification.name",

  "java.vm.specification.vendor",

  "java.vm.version",

  "java.vm.name",

  "java.vm.vendor",

  "java.vm.info",

  "jdk.debug",

  "java.library.path",

  "java.class.path",

  "java.version",

  "java.home",

  NULL

};

// unstable interface, supported counters

static const char* property_counters_us[] = {

  NULL

};

// unstable interface, unsupported counters

static const char* property_counters_uu[] = {

  "sun.boot.library.path",

  NULL

};

typedef struct {

  const char** property_list;

  CounterNS name_space;

} PropertyCounters;

static PropertyCounters property_counters[] = {

  { property_counters_ss, JAVA_PROPERTY },

  { property_counters_us, COM_PROPERTY },

  { property_counters_uu, SUN_PROPERTY },

  { NULL, SUN_PROPERTY }

};

/*

 * Method to create PerfData string instruments that contain the values

 * of various system properties. String instruments are created for each

 * property specified in the property lists provided in property_counters[].

 * Property counters have a counter name space prefix prepended to the

 * property name as indicated in property_counters[].

 */

void StatSampler::create_system_property_instrumentation(TRAPS) {

  ResourceMark rm;

  for (int i = 0; property_counters[i].property_list != NULL; i++) {

    for (int j = 0; property_counters[i].property_list[j] != NULL; j++) {

      const char* property_name = property_counters[i].property_list[j];

      assert(property_name != NULL, "property name should not be NULL");

      const char* value = get_system_property(property_name, CHECK);

      // the property must exist

      assert(value != NULL, "property name should be valid");

      if (value != NULL) {

        // create the property counter

        PerfDataManager::create_string_constant(property_counters[i].name_space,

                                                property_name, value, CHECK);

      }

    }

  }

}

/*

 * The create_misc_perfdata() method provides a place to create

 * PerfData instances that would otherwise have no better place

 * to exist.

 */

void StatSampler::create_misc_perfdata() {

  ResourceMark rm;

  EXCEPTION_MARK;

  // numeric constants

  // frequency of the native high resolution timer

  PerfDataManager::create_constant(SUN_OS, "hrt.frequency",

                                   PerfData::U_Hertz, os::elapsed_frequency(),

                                   CHECK);

  // string constants

  // create string instrumentation for various Java properties.

  create_system_property_instrumentation(CHECK);

  // HotSpot flags (from .hotspotrc) and args (from command line)

  //

  PerfDataManager::create_string_constant(JAVA_RT, "vmFlags",

                                          Arguments::jvm_flags(), CHECK);

  PerfDataManager::create_string_constant(JAVA_RT, "vmArgs",

                                          Arguments::jvm_args(), CHECK);

  // java class name/jar file and arguments to main class

  // note: name is cooridnated with launcher and Arguments.cpp

  PerfDataManager::create_string_constant(SUN_RT, "javaCommand",

                                          Arguments::java_command(), CHECK);

  // the Java VM Internal version string

  PerfDataManager::create_string_constant(SUN_RT, "internalVersion",

                                         VM_Version::internal_vm_info_string(),

                                         CHECK);

  // create sampled instrumentation objects

  create_sampled_perfdata();

}

/*

 * helper class to provide for sampling of the elapsed_counter value

 * maintained in the OS class.

 */

class HighResTimeSampler : public PerfSampleHelper {

  public:

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

};

/*

 * the create_sampled_perdata() method provides a place to instantiate

 * sampled PerfData instances that would otherwise have no better place

 * to exist.

 */

void StatSampler::create_sampled_perfdata() {

  EXCEPTION_MARK;

  // setup sampling of the elapsed time counter maintained in the

  // the os class. This counter can be used as either a time stamp

  // for each logged entry or as a liveness indicator for the VM.

  PerfSampleHelper* psh = new HighResTimeSampler();

  PerfDataManager::create_counter(SUN_OS, "hrt.ticks",

                                  PerfData::U_Ticks, psh, CHECK);

}

/*

 * the statSampler_exit() function is called from os_init.cpp on

 * exit of the vm.

 */

void statSampler_exit() {

  if (!UsePerfData) return;

  StatSampler::destroy();

}