Java example source code file (class_loading_stat.d)

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Java - Java tags/keywords

begin, end, interval_secs, line_sep, loaded_classes_cnt, number, sample_name, sampling_time, unloaded_classes_cnt, y\\n

The class_loading_stat.d Java example source code

#!/usr/sbin/dtrace -Zs
/*
 * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
*/

/*
 * Usage:
 *    1. class_loading_stat.d -c "java ..." INTERVAL_SECS
 *    2. class_loading_stat.d -p JAVA_PID INTERVAL_SECS
 *
 * This script collects statistics about loaded and unloaded Java classes
 * and dump current state to stdout every INTERVAL_SECS seconds.  If
 * INTERVAL_SECS is not set then 10 seconds interval is used.
 *
 */

#pragma D option quiet
#pragma D option destructive
#pragma D option defaultargs
#pragma D option aggrate=100ms


self char *str_ptr;
self string class_name;
self string package_name;

int INTERVAL_SECS;

:::BEGIN
{
    SAMPLE_NAME = "hotspot class loadin tracing";

    INTERVAL_SECS = $1 ? $1 : 10;
    SAMPLING_TIME = timestamp + INTERVAL_SECS * 1000000000ull;

    LOADED_CLASSES_CNT = 0;
    UNLOADED_CLASSES_CNT = 0;

    LINE_SEP =
    "------------------------------------------------------------------------";

    printf("BEGIN %s\n\n", SAMPLE_NAME);
}

/*
 * hotspot:::class-loaded, hotspot:::class-unloaded probe arguments:
 *  arg0: char*,        class name passed as mUTF8 string
 *  arg1: uintptr_t,    class name length
 *  arg2: void*,        class loader ID, which is unique identifier for
 *                      a class loader in the VM.
 *  arg3: uintptr_t,    class is shared or not
 */
hotspot$target:::class-loaded
{
    LOADED_CLASSES_CNT ++;

    self->str_ptr = (char*) copyin(arg0, arg1+1);
    self->str_ptr[arg1] = '\0';
    self->class_name = (string) self->str_ptr;

    self->package_name = dirname(self->class_name);

    @classes_loaded[self->package_name] = count();
}

hotspot$target:::class-unloaded
{
    UNLOADED_CLASSES_CNT ++;

    self->str_ptr = (char*) copyin(arg0, arg1+1);
    self->str_ptr[arg1] = '\0';
    self->class_name = (string) self->str_ptr;

    self->package_name = dirname(self->class_name);

    @classes_unloaded[self->package_name] = count();
}


tick-1sec
/timestamp > SAMPLING_TIME/
{
    printf("%s\n", LINE_SEP);
    printf("%Y\n", walltimestamp);
    printf("%s\n", LINE_SEP);

    printf("Loaded classes by package:\n");
    printa("%10@d %s\n", @classes_loaded);

    printf("\n");
    printf("Unloaded classes by package:\n");
    printa("%10@d %s\n", @classes_unloaded);

    printf("\n");
    printf("Number of loaded classes: %10d\n", LOADED_CLASSES_CNT);
    printf("Number of unloaded classes: %10d\n", UNLOADED_CLASSES_CNT);

    SAMPLING_TIME = timestamp + INTERVAL_SECS * 1000000000ull;
}


:::END
{
    printf("%s\n", LINE_SEP);
    printf("%Y\n", walltimestamp);
    printf("%s\n", LINE_SEP);

    printf("Loaded classes by package:\n");
    printa("%10@d %s\n", @classes_loaded);

    printf("\n");
    printf("Unloaded classes by package:\n");
    printa("%10@d %s\n", @classes_unloaded);

    printf("\n");
    printf("Number of loaded classes: %10d\n", LOADED_CLASSES_CNT);
    printf("Number of unloaded classes: %10d\n", UNLOADED_CLASSES_CNT);

    printf("\nEND of %s\n", SAMPLE_NAME);
}

syscall::rexit:entry,
syscall::exit:entry
/pid == $target/
{
   exit(0);
}