1 Copyright (c) 2003, 2005, Oracle and/or its affiliates. All rights reserved.

     2 

     3 Redistribution and use in source and binary forms, with or without

     4 modification, are permitted provided that the following conditions

     5 are met:

     6 

     7   - Redistributions of source code must retain the above copyright

     8     notice, this list of conditions and the following disclaimer.

     9 

    10   - Redistributions in binary form must reproduce the above copyright

    11     notice, this list of conditions and the following disclaimer in the

    12     documentation and/or other materials provided with the distribution.

    13 

    14   - Neither the name of Oracle nor the names of its

    15     contributors may be used to endorse or promote products derived

    16     from this software without specific prior written permission.

    17 

    18 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

    19 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

    20 THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    21 PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

    22 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    23 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    24 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    25 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

    26 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

    27 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

    28 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    29 

    30 

    31 Header for -agentlib:hprof (or -Xrunhprof) ASCII Output (JDK 5.0 JVMTI based)

    32 

    33 WARNING!  This file format is under development, and is subject to

    34 change without notice.

    35 

    36 This file contains the following types of records:

    37 

    38 THREAD START

    39 THREAD END      mark the lifetime of Java threads

    40 

    41 TRACE           represents a Java stack trace.  Each trace consists

    42                 of a series of stack frames.  Other records refer to

    43                 TRACEs to identify (1) where object allocations have

    44                 taken place, (2) the frames in which GC roots were

    45                 found, and (3) frequently executed methods.

    46 

    47 HEAP DUMP       is a complete snapshot of all live objects in the Java

    48                 heap.  Following distinctions are made:

    49 

    50                 ROOT    root set as determined by GC

    51                 CLS     classes 

    52                 OBJ     instances

    53                 ARR     arrays

    54 

    55 SITES           is a sorted list of allocation sites.  This identifies

    56                 the most heavily allocated object types, and the TRACE

    57                 at which those allocations occurred.

    58 

    59 CPU SAMPLES     is a statistical profile of program execution.  The VM

    60                 periodically samples all running threads, and assigns

    61                 a quantum to active TRACEs in those threads.  Entries

    62                 in this record are TRACEs ranked by the percentage of

    63                 total quanta they consumed; top-ranked TRACEs are

    64                 typically hot spots in the program.

    65 

    66 CPU TIME        is a profile of program execution obtained by measuring

    67                 the time spent in individual methods (excluding the time

    68                 spent in callees), as well as by counting the number of

    69                 times each method is called. Entries in this record are

    70                 TRACEs ranked by the percentage of total CPU time. The

    71                 "count" field indicates the number of times each TRACE 

    72                 is invoked.

    73 

    74 MONITOR TIME    is a profile of monitor contention obtained by measuring

    75                 the time spent by a thread waiting to enter a monitor.

    76                 Entries in this record are TRACEs ranked by the percentage

    77                 of total monitor contention time and a brief description

    78                 of the monitor.  The "count" field indicates the number of 

    79                 times the monitor was contended at that TRACE.

    80 

    81 MONITOR DUMP    is a complete snapshot of all the monitors and threads in 

    82                 the System.

    83 

    84 HEAP DUMP, SITES, CPU SAMPLES|TIME and MONITOR DUMP|TIME records are generated 

    85 at program exit.  They can also be obtained during program execution by typing 

    86 Ctrl-\ (on Solaris) or by typing Ctrl-Break (on Win32).