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GC.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common
 * Development and Distribution License("CDDL") (collectively, the
 * "License"). You may not use this file except in compliance with the
 * License. You can obtain a copy of the License at
 * http://www.netbeans.org/cddl-gplv2.html
 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
 * specific language governing permissions and limitations under the
 * License.  When distributing the software, include this License Header
 * Notice in each file and include the License file at
 * nbbuild/licenses/CDDL-GPL-2-CP.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the GPL Version 2 section of the License file that
 * accompanied this code. If applicable, add the following below the
 * License Header, with the fields enclosed by brackets [] replaced by
 * your own identifying information:
 * "Portions Copyrighted [year] [name of copyright owner]"
 *
 * Contributor(s):
 *
 * The Original Software is NetBeans. The Initial Developer of the Original
 * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
 * Microsystems, Inc. All Rights Reserved.
 *
 * If you wish your version of this file to be governed by only the CDDL
 * or only the GPL Version 2, indicate your decision by adding
 * "[Contributor] elects to include this software in this distribution
 * under the [CDDL or GPL Version 2] license." If you do not indicate a
 * single choice of license, a recipient has the option to distribute
 * your version of this file under either the CDDL, the GPL Version 2 or
 * to extend the choice of license to its licensees as provided above.
 * However, if you add GPL Version 2 code and therefore, elected the GPL
 * Version 2 license, then the option applies only if the new code is
 * made subject to such option by the copyright holder.
 */
/*
 * author Tomas Hurka
 *        Ian Formanek
 *        Misha Dmitriev
 */

#ifdef WIN32
#include <Windows.h>
#else
#include <sys/time.h>
#include <fcntl.h>
#include <time.h>
#endif

#ifdef SOLARIS
#define _STRUCTURED_PROC 1
#include <sys/procfs.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>

#include "jni.h"
#include "jvmti.h"

#include "org_netbeans_lib_profiler_server_system_GC.h"

#include "common_functions.h"

#define OBSERVED_PERIODS   10  /* must match OBSERVED_PERIODS in GC.java */
#define OBJECT_INT_SIZE 2
#define OBJECT_SIZE (sizeof(int)*OBJECT_INT_SIZE)

static int gc_epoch_counter, start_index, end_index;
static jlong gc_start_timestamp, gc_finish_timestamp;
static jlong *run_times, *gc_times, *start_times,*finish_times;


void JNICALL register_gc_start(jvmtiEnv *jvmti_env) {
    jlong new_timestamp = get_nano_time();
    memmove(run_times, run_times + 1, (OBSERVED_PERIODS - 1) * sizeof(jlong));
    run_times[OBSERVED_PERIODS - 1] = (new_timestamp - gc_finish_timestamp);
    start_times[start_index] = new_timestamp;
    start_index = (start_index+1) % OBSERVED_PERIODS;
    gc_start_timestamp = new_timestamp;
}


void JNICALL register_gc_finish(jvmtiEnv *jvmti_env) {
    jlong new_timestamp = get_nano_time();
    memmove(gc_times, gc_times + 1, (OBSERVED_PERIODS - 1) * sizeof(jlong));
    gc_times[OBSERVED_PERIODS - 1] = (new_timestamp - gc_start_timestamp);
    finish_times[end_index] = new_timestamp;
    end_index = (end_index+1) % OBSERVED_PERIODS;
    gc_finish_timestamp = new_timestamp;
    gc_epoch_counter++;
}


void enable_gc_start_finish_hook(JNIEnv *env, jboolean enable) {
    jvmtiError res;
    jvmtiEventMode mode;
  
    if (enable) {
        _jvmti_callbacks->GarbageCollectionStart = register_gc_start;
        _jvmti_callbacks->GarbageCollectionFinish = register_gc_finish;
        res = (*_jvmti)->SetEventCallbacks(_jvmti, _jvmti_callbacks, sizeof(*_jvmti_callbacks));
        assert(res == JVMTI_ERROR_NONE);
        mode = JVMTI_ENABLE;
    } else {
        mode = JVMTI_DISABLE;
    }
  
    res = (*_jvmti)->SetEventNotificationMode(_jvmti, mode, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL);
    assert(res == JVMTI_ERROR_NONE);
    res = (*_jvmti)->SetEventNotificationMode(_jvmti, mode, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL);
    assert(res == JVMTI_ERROR_NONE);
}


/*
 * Class:     profiler_server_system_GC
 * Method:    activateGCEpochCounter
 * Signature: (Z)V
 */
JNIEXPORT void JNICALL Java_org_netbeans_lib_profiler_server_system_GC_activateGCEpochCounter
  (JNIEnv *env, jclass clz, jboolean activate) 
{  
    enable_gc_start_finish_hook(env, activate);
    gc_epoch_counter = 0;
  
    run_times = (jlong*) calloc(OBSERVED_PERIODS, sizeof(jlong));
    gc_times = (jlong*) calloc(OBSERVED_PERIODS, sizeof(jlong));
    start_times = (jlong*) calloc(OBSERVED_PERIODS, sizeof(jlong));
    finish_times = (jlong*) calloc(OBSERVED_PERIODS, sizeof(jlong));
  
    gc_finish_timestamp = get_nano_time();  /* We know this doesn't happen during GC */
}


/*
 * Class:     profiler_server_system_GC
 * Method:    resetGCEpochCounter
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_org_netbeans_lib_profiler_server_system_GC_resetGCEpochCounter
    (JNIEnv *env, jclass clz) 
{
    gc_epoch_counter = 0;
}


/*
 * Class:     profiler_server_system_GC
 * Method:    getCurrentGCEpoch
 * Signature: ()I
 */
JNIEXPORT jint JNICALL Java_org_netbeans_lib_profiler_server_system_GC_getCurrentGCEpoch
    (JNIEnv *env, jclass clz) 
{
    return gc_epoch_counter;
}


/*
 * Class:     profiler_server_system_GC
 * Method:    objectsAdjacent
 * Signature: (Ljava/lang/Object;Ljava/lang/Object;)Z
 */
JNIEXPORT jboolean JNICALL Java_org_netbeans_lib_profiler_server_system_GC_objectsAdjacent
    (JNIEnv *env, jclass clz, jobject jobj1, jobject jobj2) 
{
    /* Warning: this assumes the HotSpot VM and its current object handle format */
    char* obj1 = jobj1 == NULL ? (char*) NULL : *((char**)(jobj1));
    char* obj2 = jobj2 == NULL ? (char*) NULL : *((char**)(jobj2));
    int diff = obj2 - obj1;
    return (diff == OBJECT_SIZE) || (diff == -OBJECT_SIZE);
}


/*
 * Class:     profiler_server_system_GC
 * Method:    getGCRelativeTimeMetrics
 * Signature: ([J)V
 */
JNIEXPORT void JNICALL Java_org_netbeans_lib_profiler_server_system_GC_getGCRelativeTimeMetrics
  (JNIEnv *env, jclass clz, jlongArray metrics) 
{
    int i;
    jlong total_gc_time = 0, total_run_time = 0;
    jlong gc_pause_rel_time, last_gc_pause_in_micro;
  
    for (i = 0; i < OBSERVED_PERIODS; i++) {
        total_gc_time += gc_times[i];
    }
    
    for (i = 0; i < OBSERVED_PERIODS; i++) {
        total_run_time += run_times[i];
    }
    
    /* We know this doesn't happen during GC, so we can calculate real run time */
    total_run_time += (get_nano_time() - gc_finish_timestamp);
  
    if (total_run_time == 0) {
        gc_pause_rel_time = 0;
    } else {
        gc_pause_rel_time = (jlong) (((float) total_gc_time) / ((float) (total_gc_time + total_run_time)) * 1000);
    }
    last_gc_pause_in_micro = gc_times[OBSERVED_PERIODS - 1] * 1000000 / 1000000000;
  
    (*env)->SetLongArrayRegion(env, metrics, 0, 1, &gc_pause_rel_time);
    (*env)->SetLongArrayRegion(env, metrics, 1, 1, &last_gc_pause_in_micro);
}

/*
 * Class:     org_netbeans_lib_profiler_server_system_GC
 * Method:    getGCStartFinishTimes
 * Signature: ([J[J)V
 */
JNIEXPORT void JNICALL Java_org_netbeans_lib_profiler_server_system_GC_getGCStartFinishTimes
  (JNIEnv *env, jclass clz, jlongArray start, jlongArray finish)
{
    (*env)->SetLongArrayRegion(env, start, 0, OBSERVED_PERIODS, start_times);
    (*env)->SetLongArrayRegion(env, finish, 0, OBSERVED_PERIODS, finish_times);
}

/*
 * Class:     profiler_server_system_GC
 * Method:    runGC
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_org_netbeans_lib_profiler_server_system_GC_runGC
  (JNIEnv *env, jclass clz) 
{
    (*_jvmti)->ForceGarbageCollection(_jvmti);
}

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