rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 1 | '\" t |
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| 24 | .\" Arch: generic |
| 25 | .\" Software: JDK 8 |
| 26 | .\" Date: 10 May 2011 |
| 27 | .\" SectDesc: Monitoring Tools |
| 28 | .\" Title: jstat.1 |
| 29 | .\" |
| 30 | .if n .pl 99999 |
| 31 | .TH jstat 1 "10 May 2011" "JDK 8" "Monitoring Tools" |
| 32 | .\" -----------------------------------------------------------------
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| 33 | .\" * Define some portability stuff
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| 35 | .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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| 36 | .\" http://bugs.debian.org/507673
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| 37 | .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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| 38 | .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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| 39 | .ie \n(.g .ds Aq \(aq
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| 40 | .el .ds Aq '
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| 41 | .\" -----------------------------------------------------------------
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| 42 | .\" * set default formatting
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| 43 | .\" -----------------------------------------------------------------
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| 44 | .\" disable hyphenation
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| 45 | .nh
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| 46 | .\" disable justification (adjust text to left margin only)
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| 47 | .ad l
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| 48 | .\" -----------------------------------------------------------------
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| 49 | .\" * MAIN CONTENT STARTS HERE *
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| 50 | .\" -----------------------------------------------------------------
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tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 51 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 52 | .SH NAME |
| 53 | jstat \- Monitors Java Virtual Machine (JVM) statistics\&. This command is experimental and unsupported\&. |
| 54 | .SH SYNOPSIS |
| 55 | .sp |
| 56 | .nf |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 57 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 58 | \fBjstat\fR [ \fIgeneralOption\fR | \fIoutputOptions vmid\fR [ \fIinterval\fR[s|ms] [ \fIcount \fR] ] |
| 59 | .fi |
| 60 | .sp |
| 61 | .TP |
| 62 | \fIgeneralOption\fR |
| 63 | A single general command-line option \f3-help\fR or \f3-options\fR\&. See General Options\&. |
| 64 | .TP |
| 65 | \fIoutputOptions\fR |
| 66 | One or more output options that consist of a single \f3statOption\fR, plus any of the \f3-t\fR, \f3-h\fR, and \f3-J\fR options\&. See Output Options\&. |
| 67 | .TP |
| 68 | \fIvmid\fR |
| 69 | Virtual machine identifier, which is a string that indicates the target JVM\&. The general syntax is the following: |
| 70 | .sp |
| 71 | .nf |
| 72 | \f3[protocol:][//]lvmid[@hostname[:port]/servername]\fP |
| 73 | .fi |
| 74 | .nf |
| 75 | \f3\fP |
| 76 | .fi |
| 77 | .sp |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 78 | |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 79 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 80 | The syntax of the \f3vmid\fR string corresponds to the syntax of a URI\&. The \f3vmid\fR string can vary from a simple integer that represents a local JVM to a more complex construction that specifies a communications protocol, port number, and other implementation-specific values\&. See Virtual Machine Identifier\&. |
| 81 | .TP |
| 82 | \fIinterval\fR [s|ms] |
| 83 | Sampling interval in the specified units, seconds (s) or milliseconds (ms)\&. Default units are milliseconds\&. Must be a positive integer\&. When specified, the \f3jstat\fR command produces its output at each interval\&. |
| 84 | .TP |
| 85 | \fIcount\fR |
| 86 | Number of samples to display\&. The default value is infinity which causes the \f3jstat\fR command to display statistics until the target JVM terminates or the \f3jstat\fR command is terminated\&. This value must be a positive integer\&. |
| 87 | .SH DESCRIPTION |
| 88 | The \f3jstat\fR command displays performance statistics for an instrumented Java HotSpot VM\&. The target JVM is identified by its virtual machine identifier, or \f3vmid\fR option\&. |
| 89 | .SH VIRTUAL\ MACHINE\ IDENTIFIER |
| 90 | The syntax of the \f3vmid\fR string corresponds to the syntax of a URI: |
| 91 | .sp |
| 92 | .nf |
| 93 | \f3[protocol:][//]lvmid[@hostname[:port]/servername]\fP |
| 94 | .fi |
| 95 | .nf |
| 96 | \f3\fP |
| 97 | .fi |
| 98 | .sp |
| 99 | .TP |
| 100 | \fIprotocol\fR |
| 101 | The communications protocol\&. If the \fIprotocol\fR value is omitted and a host name is not specified, then the default protocol is a platform-specific optimized local protocol\&. If the \fIprotocol\fR value is omitted and a host name is specified, then the default protocol is \f3rmi\fR\&. |
| 102 | .TP |
| 103 | \fIlvmid\fR |
| 104 | The local virtual machine identifier for the target JVM\&. The \f3lvmid\fR is a platform-specific value that uniquely identifies a JVM on a system\&. The \f3lvmid\fR is the only required component of a virtual machine identifier\&. The \f3lvmid\fR is typically, but not necessarily, the operating system\&'s process identifier for the target JVM process\&. You can use the \f3jps\fR command to determine the \f3lvmid\fR\&. Also, you can determine the \f3lvmid\fR on UNIX platforms with the \f3ps\fR command, and on Windows with the Windows Task Manager\&. |
| 105 | .TP |
| 106 | \fIhostname\fR |
| 107 | A hostname or IP address that indicates the target host\&. If the \fIhostname\fR value is omitted, then the target host is the local host\&. |
| 108 | .TP |
| 109 | \fIport\fR |
| 110 | The default port for communicating with the remote server\&. If the \fIhostname\fR value is omitted or the \fIprotocol\fR value specifies an optimized, local protocol, then the \fIport\fR value is ignored\&. Otherwise, treatment of the \f3port\fR parameter is implementation-specific\&. For the default \f3rmi\fR protocol, the port value indicates the port number for the rmiregistry on the remote host\&. If the \fIport\fR value is omitted and the \fIprotocol\fR value indicates \f3rmi\fR, then the default rmiregistry port (1099) is used\&. |
| 111 | .TP |
| 112 | \fIservername\fR |
| 113 | The treatment of the \f3servername\fR parameter depends on implementation\&. For the optimized local protocol, this field is ignored\&. For the \f3rmi\fR protocol, it represents the name of the RMI remote object on the remote host\&. |
| 114 | .SH OPTIONS |
| 115 | The \f3jstat\fR command supports two types of options, general options and output options\&. General options cause the \f3jstat\fR command to display simple usage and version information\&. Output options determine the content and format of the statistical output\&. |
| 116 | .PP |
| 117 | All options and their functionality are subject to change or removal in future releases\&. |
| 118 | .SS GENERAL\ OPTIONS |
| 119 | If you specify one of the general options, then you cannot specify any other option or parameter\&. |
| 120 | .TP |
| 121 | -help |
| 122 | .br |
| 123 | Displays a help message\&. |
| 124 | .TP |
| 125 | -options |
| 126 | .br |
| 127 | Displays a list of static options\&. See Output Options\&. |
| 128 | .SS OUTPUT\ OPTIONS |
| 129 | If you do not specify a general option, then you can specify output options\&. Output options determine the content and format of the \f3jstat\fR command\&'s output, and consist of a single \f3statOption\fR, plus any of the other output options (\f3-h\fR, \f3-t\fR, and \f3-J\fR)\&. The \f3statOption\fR must come first\&. |
| 130 | .PP |
| 131 | Output is formatted as a table, with columns that are separated by spaces\&. A header row with titles describes the columns\&. Use the \f3-h\fR option to set the frequency at which the header is displayed\&. Column header names are consistent among the different options\&. In general, if two options provide a column with the same name, then the data source for the two columns is the same\&. |
| 132 | .PP |
| 133 | Use the \f3-t\fR option to display a time stamp column, labeled Timestamp as the first column of output\&. The Timestamp column contains the elapsed time, in seconds, since the target JVM started\&. The resolution of the time stamp is dependent on various factors and is subject to variation due to delayed thread scheduling on heavily loaded systems\&. |
| 134 | .PP |
| 135 | Use the interval and count parameters to determine how frequently and how many times, respectively, the \f3jstat\fR command displays its output\&. |
| 136 | .PP |
| 137 | \fINote:\fR Do not to write scripts to parse the \f3jstat\fR command\&'s output because the format might change in future releases\&. If you write scripts that parse \f3jstat\fR command output, then expect to modify them for future releases of this tool\&. |
| 138 | .TP |
| 139 | -\fIstatOption\fR |
| 140 | .br |
| 141 | Determines the statistics information the \f3jstat\fR command displays\&. The following lists the available options\&. Use the \f3-options\fR general option to display the list of options for a particular platform installation\&. See Stat Options and Output\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 142 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 143 | \f3class\fR: Displays statistics about the behavior of the class loader\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 144 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 145 | \f3compiler\fR: Displays statistics about the behavior of the Java HotSpot VM Just-in-Time compiler\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 146 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 147 | \f3gc\fR: Displays statistics about the behavior of the garbage collected heap\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 148 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 149 | \f3gccapacity\fR: Displays statistics about the capacities of the generations and their corresponding spaces\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 150 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 151 | \f3gccause\fR: Displays a summary about garbage collection statistics (same as \f3-gcutil\fR), with the cause of the last and current (when applicable) garbage collection events\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 152 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 153 | \f3gcnew\fR: Displays statistics of the behavior of the new generation\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 154 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 155 | \f3gcnewcapacity\fR: Displays statistics about the sizes of the new generations and its corresponding spaces\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 156 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 157 | \f3gcold\fR: Displays statistics about the behavior of the old generation and Metaspace Statistics\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 158 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 159 | \f3gcoldcapacity\fR: Displays statistics about the sizes of the old generation\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 160 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 161 | \f3gcmetacapacity\fR: Displays statistics about the sizes of the metaspace\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 162 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 163 | \f3gcutil\fR: Displays a summary about garbage collection statistics\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 164 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 165 | \f3printcompilation\fR: Displays Java HotSpot VM compilation method statistics\&. |
| 166 | .TP |
| 167 | -h \fIn\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 168 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 169 | Displays a column header every \fIn\fR samples (output rows), where \fIn\fR is a positive integer\&. Default value is 0, which displays the column header the first row of data\&. |
| 170 | .TP |
| 171 | -t |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 172 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 173 | Display sa timestamp column as the first column of output\&. The time stamp is the time since the start time of the target JVM\&. |
| 174 | .TP |
| 175 | -J\fIjavaOption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 176 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 177 | Passes \f3javaOption\fR to the Java application launcher\&. For example, \f3-J-Xms48m\fR sets the startup memory to 48 MB\&. For a complete list of options, see java(1)\&. |
| 178 | .SS STAT\ OPTIONS\ AND\ OUTPUT |
| 179 | The following information summarizes the columns that the \f3jstat\fR command outputs for each \fIstatOption\fR\&. |
| 180 | .TP |
| 181 | -class \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 182 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 183 | Class loader statistics\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 184 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 185 | \f3Loaded\fR: Number of classes loaded\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 186 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 187 | \f3Bytes\fR: Number of KBs loaded\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 188 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 189 | \f3Unloaded\fR: Number of classes unloaded\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 190 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 191 | \f3Bytes\fR: Number of Kbytes unloaded\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 192 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 193 | \f3Time\fR: Time spent performing class loading and unloading operations\&. |
| 194 | .TP |
| 195 | -compiler \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 196 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 197 | Java HotSpot VM Just-in-Time compiler statistics\&. |
| 198 | |
| 199 | \f3Compiled\fR: Number of compilation tasks performed\&. |
| 200 | |
| 201 | \f3Failed\fR: Number of compilations tasks failed\&. |
| 202 | |
| 203 | \f3Invalid\fR: Number of compilation tasks that were invalidated\&. |
| 204 | |
| 205 | \f3Time\fR: Time spent performing compilation tasks\&. |
| 206 | |
| 207 | \f3FailedType\fR: Compile type of the last failed compilation\&. |
| 208 | |
| 209 | \f3FailedMethod\fR: Class name and method of the last failed compilation\&. |
| 210 | .TP |
| 211 | -gc \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 212 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 213 | Garbage-collected heap statistics\&. |
| 214 | |
| 215 | \f3S0C\fR: Current survivor space 0 capacity (KB)\&. |
| 216 | |
| 217 | \f3S1C\fR: Current survivor space 1 capacity (KB)\&. |
| 218 | |
| 219 | \f3S0U\fR: Survivor space 0 utilization (KB)\&. |
| 220 | |
| 221 | \f3S1U\fR: Survivor space 1 utilization (KB)\&. |
| 222 | |
| 223 | \f3EC\fR: Current eden space capacity (KB)\&. |
| 224 | |
| 225 | \f3EU\fR: Eden space utilization (KB)\&. |
| 226 | |
| 227 | \f3OC\fR: Current old space capacity (KB)\&. |
| 228 | |
| 229 | \f3OU\fR: Old space utilization (KB)\&. |
| 230 | |
| 231 | \f3MC\fR: Metaspace capacity (KB)\&. |
| 232 | |
| 233 | \f3MU\fR: Metacspace utilization (KB)\&. |
| 234 | |
| 235 | \f3YGC\fR: Number of young generation garbage collection events\&. |
| 236 | |
| 237 | \f3YGCT\fR: Young generation garbage collection time\&. |
| 238 | |
| 239 | \f3FGC\fR: Number of full GC events\&. |
| 240 | |
| 241 | \f3FGCT\fR: Full garbage collection time\&. |
| 242 | |
| 243 | \f3GCT\fR: Total garbage collection time\&. |
| 244 | .TP |
| 245 | -gccapacity \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 246 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 247 | Memory pool generation and space capacities\&. |
| 248 | |
| 249 | \f3NGCMN\fR: Minimum new generation capacity (KB)\&. |
| 250 | |
| 251 | \f3NGCMX\fR: Maximum new generation capacity (KB)\&. |
| 252 | |
| 253 | \f3NGC\fR: Current new generation capacity (KB)\&. |
| 254 | |
| 255 | \f3S0C\fR: Current survivor space 0 capacity (KB)\&. |
| 256 | |
| 257 | \f3S1C\fR: Current survivor space 1 capacity (KB)\&. |
| 258 | |
| 259 | \f3EC\fR: Current eden space capacity (KB)\&. |
| 260 | |
| 261 | \f3OGCMN\fR: Minimum old generation capacity (KB)\&. |
| 262 | |
| 263 | \f3OGCMX\fR: Maximum old generation capacity (KB)\&. |
| 264 | |
| 265 | \f3OGC\fR: Current old generation capacity (KB)\&. |
| 266 | |
| 267 | \f3OC\fR: Current old space capacity (KB)\&. |
| 268 | |
| 269 | \f3MCMN\fR: Minimum metaspace capacity (KB)\&. |
| 270 | |
| 271 | \f3MCMX\fR: Maximum metaspace capacity (KB)\&. |
| 272 | |
| 273 | \f3MC\fR: Metaspace capacity (KB)\&. |
| 274 | |
| 275 | \f3YGC\fR: Number of Young generation GC Events\&. |
| 276 | |
| 277 | \f3FGC\fR: Number of Full GC Events\&. |
| 278 | .TP |
| 279 | -gccause \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 280 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 281 | This option displays the same summary of garbage collection statistics as the \f3-gcutil\fR option, but includes the causes of the last garbage collection event and (when applicable) the current garbage collection event\&. In addition to the columns listed for \f3-gcutil\fR, this option adds the following columns\&. |
| 282 | |
| 283 | Garbage collection statistics, including garbage collection Events\&. |
| 284 | |
| 285 | \f3LGCC\fR: Cause of last garbage collection\&. |
| 286 | |
| 287 | \f3GCC\fR: Cause of current garbage collection\&. |
| 288 | .TP |
| 289 | -gcnew \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 290 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 291 | New generation statistics\&. |
| 292 | |
| 293 | \f3S0C\fR: Current survivor space 0 capacity (KB)\&. |
| 294 | |
| 295 | \f3S1C\fR: Current survivor space 1 capacity (KB)\&. |
| 296 | |
| 297 | \f3S0U\fR: Survivor space 0 utilization (KB)\&. |
| 298 | |
| 299 | \f3S1U\fR: Survivor space 1 utilization (KB)\&. |
| 300 | |
| 301 | \f3TT\fR: Tenuring threshold\&. |
| 302 | |
| 303 | \f3MTT\fR: Maximum tenuring threshold\&. |
| 304 | |
| 305 | \f3DSS\fR: Desired survivor size (KB)\&. |
| 306 | |
| 307 | \f3EC\fR: Current eden space capacity (KB)\&. |
| 308 | |
| 309 | \f3EU\fR: Eden space utilization (KB)\&. |
| 310 | |
| 311 | \f3YGC\fR: Number of young generation GC events\&. |
| 312 | |
| 313 | \f3YGCT\fR: Young generation garbage collection time\&. |
| 314 | .TP |
| 315 | -gcnewcapacity \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 316 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 317 | New generation space size statistics\&. |
tbell | 16c34dd | 2009-05-04 18:28:26 -0700 | [diff] [blame] | 318 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 319 | NGCMN: Minimum new generation capacity (KB)\&. |
| 320 | |
| 321 | \f3NGCMX\fR: Maximum new generation capacity (KB)\&. |
| 322 | |
| 323 | \f3NGC\fR: Current new generation capacity (KB)\&. |
| 324 | |
| 325 | \f3S0CMX\fR: Maximum survivor space 0 capacity (KB)\&. |
| 326 | |
| 327 | \f3S0C\fR: Current survivor space 0 capacity (KB)\&. |
| 328 | |
| 329 | \f3S1CMX\fR: Maximum survivor space 1 capacity (KB)\&. |
| 330 | |
| 331 | \f3S1C\fR: Current survivor space 1 capacity (KB)\&. |
| 332 | |
| 333 | \f3ECMX\fR: Maximum eden space capacity (KB)\&. |
| 334 | |
| 335 | \f3EC\fR: Current eden space capacity (KB)\&. |
| 336 | |
| 337 | \f3YGC\fR: Number of young generation GC events\&. |
| 338 | |
| 339 | \f3FGC\fR: Number of Full GC Events\&. |
| 340 | .TP |
| 341 | -gcold \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 342 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 343 | old and permanent generation statistics\&. |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 344 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 345 | \f3MC\fR: Metaspace capacity (KB)\&. |
| 346 | |
| 347 | \f3MU\fR: Metaspace utilization (KB)\&. |
| 348 | |
| 349 | \f3OC\fR: Current old space capacity (KB)\&. |
| 350 | |
| 351 | \f3OU\fR: old space utilization (KB)\&. |
| 352 | |
| 353 | \f3YGC\fR: Number of young generation GC events\&. |
| 354 | |
| 355 | \f3FGC\fR: Number of full GC events\&. |
| 356 | |
| 357 | \f3FGCT\fR: Full garbage collection time\&. |
| 358 | |
| 359 | \f3GCT\fR: Total garbage collection time\&. |
| 360 | .TP |
| 361 | -gcoldcapacity \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 362 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 363 | Old generation statistics\&. |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 364 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 365 | \f3OGCMN\fR: Minimum old generation capacity (KB)\&. |
| 366 | |
| 367 | \f3OGCMX\fR: Maximum old generation capacity (KB)\&. |
| 368 | |
| 369 | \f3OGC\fR: Current old generation capacity (KB)\&. |
| 370 | |
| 371 | \f3OC\fR: Current old space capacity (KB)\&. |
| 372 | |
| 373 | \f3YGC\fR: Number of young generation GC events\&. |
| 374 | |
| 375 | \f3FGC\fR: Number of full GC events\&. |
| 376 | |
| 377 | \f3FGCT\fR: Full garbage collection time\&. |
| 378 | |
| 379 | \f3GCT\fR: Total garbage collection time\&. |
| 380 | .TP |
| 381 | -gcmetacapacity \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 382 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 383 | Permanent generation statistics\&. |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 384 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 385 | \f3MCMN\fR: Minimum metaspace capacity (KB)\&. |
| 386 | |
| 387 | \f3MCMX\fR: Maximum metaspace capacity (KB)\&. |
| 388 | |
| 389 | \f3MC\fR: Metaspace capacity (KB)\&. |
| 390 | |
| 391 | \f3YGC\fR: Number of young generation GC events\&. |
| 392 | |
| 393 | \f3FGC\fR: Number of full GC events\&. |
| 394 | |
| 395 | \f3FGCT\fR: Full garbage collection time\&. |
| 396 | |
| 397 | \f3GCT\fR: Total garbage collection time\&. |
| 398 | .TP |
| 399 | -gcutil \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 400 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 401 | Summary of garbage collection statistics\&. |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 402 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 403 | \f3S0\fR: Survivor space 0 utilization as a percentage of the space\&'s current capacity\&. |
| 404 | |
| 405 | \f3S1\fR: Survivor space 1 utilization as a percentage of the space\&'s current capacity\&. |
| 406 | |
| 407 | \f3E\fR: Eden space utilization as a percentage of the space\&'s current capacity\&. |
| 408 | |
| 409 | \f3O\fR: Old space utilization as a percentage of the space\&'s current capacity\&. |
| 410 | |
| 411 | \f3M\fR: Metaspace utilization as a percentage of the space\&'s current capacity\&. |
| 412 | |
| 413 | \f3YGC\fR: Number of young generation GC events\&. |
| 414 | |
| 415 | \f3YGCT\fR: Young generation garbage collection time\&. |
| 416 | |
| 417 | \f3FGC\fR: Number of full GC events\&. |
| 418 | |
| 419 | \f3FGCT\fR: Full garbage collection time\&. |
| 420 | |
| 421 | \f3GCT\fR: Total garbage collection time\&. |
| 422 | .TP |
| 423 | -printcompilation \fIoption\fR |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 424 | .br |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 425 | Java HotSpot VM compiler method statistics\&. |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 426 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 427 | \f3Compiled\fR: Number of compilation tasks performed by the most recently compiled method\&. |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 428 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 429 | \f3Size\fR: Number of bytes of byte code of the most recently compiled method\&. |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 430 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 431 | \f3Type\fR: Compilation type of the most recently compiled method\&. |
duke | 6e45e10 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 432 | |
rgallard | b643545 | 2013-11-25 20:19:02 -0800 | [diff] [blame] | 433 | \f3Method\fR: Class name and method name identifying the most recently compiled method\&. Class name uses slash (/) instead of dot (\&.) as a name space separator\&. Method name is the method within the specified class\&. The format for these two fields is consistent with the HotSpot \f3-XX:+PrintComplation\fR option\&. |
| 434 | .SH EXAMPLES |
| 435 | This section presents some examples of monitoring a local JVM with an \fIlvmid\fR of 21891\&. |
| 436 | .SS THE\ GCUTIL\ OPTION |
| 437 | This example attaches to lvmid 21891 and takes 7 samples at 250 millisecond intervals and displays the output as specified by the -\f3gcutil\fR option\&. |
| 438 | .PP |
| 439 | The output of this example shows that a young generation collection occurred between the third and fourth sample\&. The collection took 0\&.001 seconds and promoted objects from the eden space (E) to the old space (O), resulting in an increase of old space utilization from 9\&.49% to 9\&.51%\&. Before the collection, the survivor space was 12\&.44% utilized, but after this collection it is only 7\&.74% utilized\&. |
| 440 | .sp |
| 441 | .nf |
| 442 | \f3jstat \-gcutil 21891 250 7\fP |
| 443 | .fi |
| 444 | .nf |
| 445 | \f3 S0 S1 E O M YGC YGCT FGC FGCT GCT\fP |
| 446 | .fi |
| 447 | .nf |
| 448 | \f30\&.00 99\&.74 13\&.49 7\&.86 95\&.82 3 0\&.124 0 0\&.000 0\&.124\fP |
| 449 | .fi |
| 450 | .nf |
| 451 | \f30\&.00 99\&.74 13\&.49 7\&.86 95\&.82 3 0\&.124 0 0\&.000 0\&.124\fP |
| 452 | .fi |
| 453 | .nf |
| 454 | \f30\&.00 99\&.74 13\&.49 7\&.86 95\&.82 3 0\&.124 0 0\&.000 0\&.124\fP |
| 455 | .fi |
| 456 | .nf |
| 457 | \f30\&.00 99\&.74 13\&.49 7\&.86 95\&.82 3 0\&.124 0 0\&.000 0\&.124\fP |
| 458 | .fi |
| 459 | .nf |
| 460 | \f30\&.00 99\&.74 13\&.80 7\&.86 95\&.82 3 0\&.124 0 0\&.000 0\&.124\fP |
| 461 | .fi |
| 462 | .nf |
| 463 | \f30\&.00 99\&.74 13\&.80 7\&.86 95\&.82 3 0\&.124 0 0\&.000 0\&.124\fP |
| 464 | .fi |
| 465 | .nf |
| 466 | \f30\&.00 99\&.74 13\&.80 7\&.86 95\&.82 3 0\&.124 0 0\&.000 0\&.124\fP |
| 467 | .fi |
| 468 | .nf |
| 469 | \f3\fP |
| 470 | .fi |
| 471 | .sp |
| 472 | .SS REPEAT\ THE\ COLUMN\ HEADER\ STRING |
| 473 | This example attaches to lvmid 21891 and takes samples at 250 millisecond intervals and displays the output as specified by \f3-gcutil\fR option\&. In addition, it uses the \f3-h3\fR option to output the column header after every 3 lines of data\&. |
| 474 | .PP |
| 475 | In addition to showing the repeating header string, this example shows that between the second and third samples, a young GC occurred\&. Its duration was 0\&.001 seconds\&. The collection found enough active data that the survivor space 0 utilization (S0U) would have exceeded the desired survivor Size (DSS)\&. As a result, objects were promoted to the old generation (not visible in this output), and the tenuring threshold (TT) was lowered from 31 to 2\&. |
| 476 | .PP |
| 477 | Another collection occurs between the fifth and sixth samples\&. This collection found very few survivors and returned the tenuring threshold to 31\&. |
| 478 | .sp |
| 479 | .nf |
| 480 | \f3jstat \-gcnew \-h3 21891 250\fP |
| 481 | .fi |
| 482 | .nf |
| 483 | \f3 S0C S1C S0U S1U TT MTT DSS EC EU YGC YGCT\fP |
| 484 | .fi |
| 485 | .nf |
| 486 | \f3 64\&.0 64\&.0 0\&.0 31\&.7 31 31 32\&.0 512\&.0 178\&.6 249 0\&.203\fP |
| 487 | .fi |
| 488 | .nf |
| 489 | \f3 64\&.0 64\&.0 0\&.0 31\&.7 31 31 32\&.0 512\&.0 355\&.5 249 0\&.203\fP |
| 490 | .fi |
| 491 | .nf |
| 492 | \f3 64\&.0 64\&.0 35\&.4 0\&.0 2 31 32\&.0 512\&.0 21\&.9 250 0\&.204\fP |
| 493 | .fi |
| 494 | .nf |
| 495 | \f3 S0C S1C S0U S1U TT MTT DSS EC EU YGC YGCT\fP |
| 496 | .fi |
| 497 | .nf |
| 498 | \f3 64\&.0 64\&.0 35\&.4 0\&.0 2 31 32\&.0 512\&.0 245\&.9 250 0\&.204\fP |
| 499 | .fi |
| 500 | .nf |
| 501 | \f3 64\&.0 64\&.0 35\&.4 0\&.0 2 31 32\&.0 512\&.0 421\&.1 250 0\&.204\fP |
| 502 | .fi |
| 503 | .nf |
| 504 | \f3 64\&.0 64\&.0 0\&.0 19\&.0 31 31 32\&.0 512\&.0 84\&.4 251 0\&.204\fP |
| 505 | .fi |
| 506 | .nf |
| 507 | \f3 S0C S1C S0U S1U TT MTT DSS EC EU YGC YGCT\fP |
| 508 | .fi |
| 509 | .nf |
| 510 | \f3 64\&.0 64\&.0 0\&.0 19\&.0 31 31 32\&.0 512\&.0 306\&.7 251 0\&.204\fP |
| 511 | .fi |
| 512 | .nf |
| 513 | \f3\fP |
| 514 | .fi |
| 515 | .sp |
| 516 | .SS INCLUDE\ A\ TIME\ STAMP\ FOR\ EACH\ SAMPLE |
| 517 | This example attaches to lvmid 21891 and takes 3 samples at 250 millisecond intervals\&. The \f3-t\fR option is used to generate a time stamp for each sample in the first column\&. |
| 518 | .PP |
| 519 | The Timestamp column reports the elapsed time in seconds since the start of the target JVM\&. In addition, the \f3-gcoldcapacity\fR output shows the old generation capacity (OGC) and the old space capacity (OC) increasing as the heap expands to meet allocation or promotion demands\&. The old generation capacity (OGC) has grown to from 11,696 KB to 13820 KB after the eighty-first full garbage collection (FGC)\&. The maximum capacity of the generation (and space) is 60,544 KB (OGCMX), so it still has room to expand\&. |
| 520 | .sp |
| 521 | .nf |
| 522 | \f3Timestamp OGCMN OGCMX OGC OC YGC FGC FGCT GCT\fP |
| 523 | .fi |
| 524 | .nf |
| 525 | \f3 150\&.1 1408\&.0 60544\&.0 11696\&.0 11696\&.0 194 80 2\&.874 3\&.799\fP |
| 526 | .fi |
| 527 | .nf |
| 528 | \f3 150\&.4 1408\&.0 60544\&.0 13820\&.0 13820\&.0 194 81 2\&.938 3\&.863\fP |
| 529 | .fi |
| 530 | .nf |
| 531 | \f3 150\&.7 1408\&.0 60544\&.0 13820\&.0 13820\&.0 194 81 2\&.938 3\&.863\fP |
| 532 | .fi |
| 533 | .nf |
| 534 | \f3\fP |
| 535 | .fi |
| 536 | .sp |
| 537 | .SS MONITOR\ INSTRUMENTATION\ FOR\ A\ REMOTE\ JVM |
| 538 | This example attaches to lvmid 40496 on the system named remote\&.domain using the \f3-gcutil\fR option, with samples taken every second indefinitely\&. |
| 539 | .PP |
| 540 | The lvmid is combined with the name of the remote host to construct a \fIvmid\fR of \f340496@remote\&.domain\fR\&. This vmid results in the use of the \f3rmi\fR protocol to communicate to the default \f3jstatd\fR server on the remote host\&. The \f3jstatd\fR server is located using the rmiregistry on \f3remote\&.domain\fR that is bound to the default rmiregistry port (port 1099)\&. |
| 541 | .sp |
| 542 | .nf |
| 543 | \f3jstat \-gcutil 40496@remote\&.domain 1000\fP |
| 544 | .fi |
| 545 | .nf |
| 546 | \f3\fI\&.\&.\&. output omitted\fR\fP |
| 547 | .fi |
| 548 | .nf |
| 549 | \f3\fP |
| 550 | .fi |
| 551 | .sp |
| 552 | .SH SEE\ ALSO |
| 553 | .TP 0.2i |
| 554 | \(bu |
| 555 | java(1) |
| 556 | .TP 0.2i |
| 557 | \(bu |
| 558 | jps(1) |
| 559 | .TP 0.2i |
| 560 | \(bu |
| 561 | jstatd(1) |
| 562 | .TP 0.2i |
| 563 | \(bu |
| 564 | rmiregistry(1) |
| 565 | .RE
|
| 566 | .br
|
| 567 | 'pl 8.5i
|
| 568 | 'bp
|