1 '\" t 2 .\" Copyright (c) 2004, 2015, Oracle and/or its affiliates. All rights reserved. 3 .\" 4 .\" DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 .\" 6 .\" This code is free software; you can redistribute it and/or modify it 7 .\" under the terms of the GNU General Public License version 2 only, as 8 .\" published by the Free Software Foundation. 9 .\" 10 .\" This code is distributed in the hope that it will be useful, but WITHOUT 11 .\" ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 .\" FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 .\" version 2 for more details (a copy is included in the LICENSE file that 14 .\" accompanied this code). 15 .\" 16 .\" You should have received a copy of the GNU General Public License version 17 .\" 2 along with this work; if not, write to the Free Software Foundation, 18 .\" Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 .\" 20 .\" Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 .\" or visit www.oracle.com if you need additional information or have any 22 .\" questions. 23 .\" 24 .\" Arch: generic 25 .\" Software: JDK 8 26 .\" Date: 03 March 2015 27 .\" SectDesc: Monitoring Tools 28 .\" Title: jstat.1 29 .\" 30 .if n .pl 99999 31 .TH jstat 1 "03 March 2015" "JDK 8" "Monitoring Tools" 32 .\" ----------------------------------------------------------------- 33 .\" * Define some portability stuff 34 .\" ----------------------------------------------------------------- 35 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 36 .\" http://bugs.debian.org/507673 37 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html 38 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 39 .ie \n(.g .ds Aq \(aq 40 .el .ds Aq ' 41 .\" ----------------------------------------------------------------- 42 .\" * set default formatting 43 .\" ----------------------------------------------------------------- 44 .\" disable hyphenation 45 .nh 46 .\" disable justification (adjust text to left margin only) 47 .ad l 48 .\" ----------------------------------------------------------------- 49 .\" * MAIN CONTENT STARTS HERE * 50 .\" ----------------------------------------------------------------- 51 52 .SH NAME 53 jstat \- Monitors Java Virtual Machine (JVM) statistics\&. This command is experimental and unsupported\&. 54 .SH SYNOPSIS 55 .sp 56 .nf 57 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 78 79 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 Solaris, Linux, and OS X 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\&. 142 143 \f3class\fR: Displays statistics about the behavior of the class loader\&. 144 145 \f3compiler\fR: Displays statistics about the behavior of the Java HotSpot VM Just-in-Time compiler\&. 146 147 \f3gc\fR: Displays statistics about the behavior of the garbage collected heap\&. 148 149 \f3gccapacity\fR: Displays statistics about the capacities of the generations and their corresponding spaces\&. 150 151 \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\&. 152 153 \f3gcnew\fR: Displays statistics of the behavior of the new generation\&. 154 155 \f3gcnewcapacity\fR: Displays statistics about the sizes of the new generations and its corresponding spaces\&. 156 157 \f3gcold\fR: Displays statistics about the behavior of the old generation and metaspace statistics\&. 158 159 \f3gcoldcapacity\fR: Displays statistics about the sizes of the old generation\&. 160 161 \f3gcmetacapacity\fR: Displays statistics about the sizes of the metaspace\&. 162 163 \f3gcutil\fR: Displays a summary about garbage collection statistics\&. 164 165 \f3printcompilation\fR: Displays Java HotSpot VM compilation method statistics\&. 166 .TP 167 -h \fIn\fR 168 .br 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 172 .br 173 Displays a 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 176 .br 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 182 .br 183 Class loader statistics\&. 184 185 \f3Loaded\fR: Number of classes loaded\&. 186 187 \f3Bytes\fR: Number of kBs loaded\&. 188 189 \f3Unloaded\fR: Number of classes unloaded\&. 190 191 \f3Bytes\fR: Number of Kbytes unloaded\&. 192 193 \f3Time\fR: Time spent performing class loading and unloading operations\&. 194 .TP 195 -compiler \fIoption\fR 196 .br 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 212 .br 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 \f3CCSC\fR: Compressed class space capacity (kB)\&. 236 237 \f3CCSU\fR: Compressed class space used (kB)\&. 238 239 \f3YGC\fR: Number of young generation garbage collection events\&. 240 241 \f3YGCT\fR: Young generation garbage collection time\&. 242 243 \f3FGC\fR: Number of full GC events\&. 244 245 \f3FGCT\fR: Full garbage collection time\&. 246 247 \f3GCT\fR: Total garbage collection time\&. 248 .TP 249 -gccapacity \fIoption\fR 250 .br 251 Memory pool generation and space capacities\&. 252 253 \f3NGCMN\fR: Minimum new generation capacity (kB)\&. 254 255 \f3NGCMX\fR: Maximum new generation capacity (kB)\&. 256 257 \f3NGC\fR: Current new generation capacity (kB)\&. 258 259 \f3S0C\fR: Current survivor space 0 capacity (kB)\&. 260 261 \f3S1C\fR: Current survivor space 1 capacity (kB)\&. 262 263 \f3EC\fR: Current eden space capacity (kB)\&. 264 265 \f3OGCMN\fR: Minimum old generation capacity (kB)\&. 266 267 \f3OGCMX\fR: Maximum old generation capacity (kB)\&. 268 269 \f3OGC\fR: Current old generation capacity (kB)\&. 270 271 \f3OC\fR: Current old space capacity (kB)\&. 272 273 \f3MCMN\fR: Minimum metaspace capacity (kB)\&. 274 275 \f3MCMX\fR: Maximum metaspace capacity (kB)\&. 276 277 \f3MC\fR: Metaspace capacity (kB)\&. 278 279 \f3CCSMN\fR: Compressed class space minimum capacity (kB)\&. 280 281 \f3CCSMX\fR: Compressed class space maximum capacity (kB)\&. 282 283 \f3CCSC\fR: Compressed class space capacity (kB)\&. 284 285 \f3YGC\fR: Number of young generation GC events\&. 286 287 \f3FGC\fR: Number of full GC events\&. 288 .TP 289 -gccause \fIoption\fR 290 .br 291 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\&. 292 293 \f3LGCC\fR: Cause of last garbage collection 294 295 \f3GCC\fR: Cause of current garbage collection 296 .TP 297 -gcnew \fIoption\fR 298 .br 299 New generation statistics\&. 300 301 \f3S0C\fR: Current survivor space 0 capacity (kB)\&. 302 303 \f3S1C\fR: Current survivor space 1 capacity (kB)\&. 304 305 \f3S0U\fR: Survivor space 0 utilization (kB)\&. 306 307 \f3S1U\fR: Survivor space 1 utilization (kB)\&. 308 309 \f3TT\fR: Tenuring threshold\&. 310 311 \f3MTT\fR: Maximum tenuring threshold\&. 312 313 \f3DSS\fR: Desired survivor size (kB)\&. 314 315 \f3EC\fR: Current eden space capacity (kB)\&. 316 317 \f3EU\fR: Eden space utilization (kB)\&. 318 319 \f3YGC\fR: Number of young generation GC events\&. 320 321 \f3YGCT\fR: Young generation garbage collection time\&. 322 .TP 323 -gcnewcapacity \fIoption\fR 324 .br 325 New generation space size statistics\&. 326 327 \f3NGCMN\fR: Minimum new generation capacity (kB)\&. 328 329 \f3NGCMX\fR: Maximum new generation capacity (kB)\&. 330 331 \f3NGC\fR: Current new generation capacity (kB)\&. 332 333 \f3S0CMX\fR: Maximum survivor space 0 capacity (kB)\&. 334 335 \f3S0C\fR: Current survivor space 0 capacity (kB)\&. 336 337 \f3S1CMX\fR: Maximum survivor space 1 capacity (kB)\&. 338 339 \f3S1C\fR: Current survivor space 1 capacity (kB)\&. 340 341 \f3ECMX\fR: Maximum eden space capacity (kB)\&. 342 343 \f3EC\fR: Current eden space capacity (kB)\&. 344 345 \f3YGC\fR: Number of young generation GC events\&. 346 347 \f3FGC\fR: Number of full GC events\&. 348 .TP 349 -gcold \fIoption\fR 350 .br 351 Old and permanent generation statistics\&. 352 353 \f3MC\fR: Metaspace capacity (kB)\&. 354 355 \f3MU\fR: Metaspace utilization (kB)\&. 356 357 \f3CCSC\fR: Compressed class space capacity (kB)\&. 358 359 \f3CCSU\fR: Compressed class space used (kB)\&. 360 361 \f3OC\fR: Current old space capacity (kB)\&. 362 363 \f3OU\fR: Old space utilization (kB)\&. 364 365 \f3YGC\fR: Number of young generation GC events\&. 366 367 \f3FGC\fR: Number of full GC events\&. 368 369 \f3FGCT\fR: Full garbage collection time\&. 370 371 \f3GCT\fR: Total garbage collection time\&. 372 .TP 373 -gcoldcapacity \fIoption\fR 374 .br 375 Old generation statistics\&. 376 377 \f3OGCMN\fR: Minimum old generation capacity (kB)\&. 378 379 \f3OGCMX\fR: Maximum old generation capacity (kB)\&. 380 381 \f3OGC\fR: Current old generation capacity (kB)\&. 382 383 \f3OC\fR: Current old space capacity (kB)\&. 384 385 \f3YGC\fR: Number of young generation GC events\&. 386 387 \f3FGC\fR: Number of full GC events\&. 388 389 \f3FGCT\fR: Full garbage collection time\&. 390 391 \f3GCT\fR: Total garbage collection time\&. 392 .TP 393 -gcmetacapacity \fIoption\fR 394 .br 395 Permanent generation statistics\&. 396 397 \f3MCMN\fR: Minimum metaspace capacity (kB)\&. 398 399 \f3MCMX\fR: Maximum metaspace capacity (kB)\&. 400 401 \f3MC\fR: Metaspace capacity (kB)\&. 402 403 \f3CCSMN\fR: Compressed class space minimum capacity (kB)\&. 404 405 \f3CCSMX\fR: Compressed class space maximum capacity (kB)\&. 406 407 \f3YGC\fR: Number of young generation GC events\&. 408 409 \f3FGC\fR: Number of full GC events\&. 410 411 \f3FGCT\fR: Full garbage collection time\&. 412 413 \f3GCT\fR: Total garbage collection time\&. 414 .TP 415 -gcutil \fIoption\fR 416 .br 417 Summary of garbage collection statistics\&. 418 419 \f3S0\fR: Survivor space 0 utilization as a percentage of the space\&'s current capacity\&. 420 421 \f3S1\fR: Survivor space 1 utilization as a percentage of the space\&'s current capacity\&. 422 423 \f3E\fR: Eden space utilization as a percentage of the space\&'s current capacity\&. 424 425 \f3O\fR: Old space utilization as a percentage of the space\&'s current capacity\&. 426 427 \f3M\fR: Metaspace utilization as a percentage of the space\&'s current capacity\&. 428 429 \f3CCS\fR: Compressed class space utilization as a percentage\&. 430 431 \f3YGC\fR: Number of young generation GC events\&. 432 433 \f3YGCT\fR: Young generation garbage collection time\&. 434 435 \f3FGC\fR: Number of full GC events\&. 436 437 \f3FGCT\fR: Full garbage collection time\&. 438 439 \f3GCT\fR: Total garbage collection time\&. 440 .TP 441 -printcompilation \fIoption\fR 442 .br 443 Java HotSpot VM compiler method statistics\&. 444 445 \f3Compiled\fR: Number of compilation tasks performed by the most recently compiled method\&. 446 447 \f3Size\fR: Number of bytes of byte code of the most recently compiled method\&. 448 449 \f3Type\fR: Compilation type of the most recently compiled method\&. 450 451 \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:+PrintCompilation\fR option\&. 452 .SH EXAMPLES 453 This section presents some examples of monitoring a local JVM with an \fIlvmid\fR of 21891\&. 454 .SS THE\ GCUTIL\ OPTION 455 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\&. 456 .PP 457 The output of this example shows that a young generation collection occurred between the third and fourth sample\&. The collection took 0\&.078 seconds and promoted objects from the eden space (E) to the old space (O), resulting in an increase of old space utilization from 66\&.80% to 68\&.19%\&. Before the collection, the survivor space was 97\&.02% utilized, but after this collection it is 91\&.03% utilized\&. 458 .sp 459 .nf 460 \f3jstat \-gcutil 21891 250 7\fP 461 .fi 462 .nf 463 \f3 S0 S1 E O M CCS YGC YGCT FGC FGCT GCT \fP 464 .fi 465 .nf 466 \f3 0\&.00 97\&.02 70\&.31 66\&.80 95\&.52 89\&.14 7 0\&.300 0 0\&.000 0\&.300\fP 467 .fi 468 .nf 469 \f3 0\&.00 97\&.02 86\&.23 66\&.80 95\&.52 89\&.14 7 0\&.300 0 0\&.000 0\&.300\fP 470 .fi 471 .nf 472 \f3 0\&.00 97\&.02 96\&.53 66\&.80 95\&.52 89\&.14 7 0\&.300 0 0\&.000 0\&.300\fP 473 .fi 474 .nf 475 \f3 91\&.03 0\&.00 1\&.98 68\&.19 95\&.89 91\&.24 8 0\&.378 0 0\&.000 0\&.378\fP 476 .fi 477 .nf 478 \f3 91\&.03 0\&.00 15\&.82 68\&.19 95\&.89 91\&.24 8 0\&.378 0 0\&.000 0\&.378\fP 479 .fi 480 .nf 481 \f3 91\&.03 0\&.00 17\&.80 68\&.19 95\&.89 91\&.24 8 0\&.378 0 0\&.000 0\&.378\fP 482 .fi 483 .nf 484 \f3 91\&.03 0\&.00 17\&.80 68\&.19 95\&.89 91\&.24 8 0\&.378 0 0\&.000 0\&.378\fP 485 .fi 486 .sp 487 .SS REPEAT\ THE\ COLUMN\ HEADER\ STRING 488 This example attaches to lvmid 21891 and takes samples at 250 millisecond intervals and displays the output as specified by \f3-gcnew\fR option\&. In addition, it uses the \f3-h3\fR option to output the column header after every 3 lines of data\&. 489 .PP 490 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\&. 491 .PP 492 Another collection occurs between the fifth and sixth samples\&. This collection found very few survivors and returned the tenuring threshold to 31\&. 493 .sp 494 .nf 495 \f3jstat \-gcnew \-h3 21891 250\fP 496 .fi 497 .nf 498 \f3 S0C S1C S0U S1U TT MTT DSS EC EU YGC YGCT\fP 499 .fi 500 .nf 501 \f3 64\&.0 64\&.0 0\&.0 31\&.7 31 31 32\&.0 512\&.0 178\&.6 249 0\&.203\fP 502 .fi 503 .nf 504 \f3 64\&.0 64\&.0 0\&.0 31\&.7 31 31 32\&.0 512\&.0 355\&.5 249 0\&.203\fP 505 .fi 506 .nf 507 \f3 64\&.0 64\&.0 35\&.4 0\&.0 2 31 32\&.0 512\&.0 21\&.9 250 0\&.204\fP 508 .fi 509 .nf 510 \f3 S0C S1C S0U S1U TT MTT DSS EC EU YGC YGCT\fP 511 .fi 512 .nf 513 \f3 64\&.0 64\&.0 35\&.4 0\&.0 2 31 32\&.0 512\&.0 245\&.9 250 0\&.204\fP 514 .fi 515 .nf 516 \f3 64\&.0 64\&.0 35\&.4 0\&.0 2 31 32\&.0 512\&.0 421\&.1 250 0\&.204\fP 517 .fi 518 .nf 519 \f3 64\&.0 64\&.0 0\&.0 19\&.0 31 31 32\&.0 512\&.0 84\&.4 251 0\&.204\fP 520 .fi 521 .nf 522 \f3 S0C S1C S0U S1U TT MTT DSS EC EU YGC YGCT\fP 523 .fi 524 .nf 525 \f3 64\&.0 64\&.0 0\&.0 19\&.0 31 31 32\&.0 512\&.0 306\&.7 251 0\&.204\fP 526 .fi 527 .nf 528 \f3\fP 529 .fi 530 .sp 531 .SS INCLUDE\ A\ TIME\ STAMP\ FOR\ EACH\ SAMPLE 532 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\&. 533 .PP 534 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 from 11,696 kB to 13,820 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\&. 535 .sp 536 .nf 537 \f3Timestamp OGCMN OGCMX OGC OC YGC FGC FGCT GCT\fP 538 .fi 539 .nf 540 \f3 150\&.1 1408\&.0 60544\&.0 11696\&.0 11696\&.0 194 80 2\&.874 3\&.799\fP 541 .fi 542 .nf 543 \f3 150\&.4 1408\&.0 60544\&.0 13820\&.0 13820\&.0 194 81 2\&.938 3\&.863\fP 544 .fi 545 .nf 546 \f3 150\&.7 1408\&.0 60544\&.0 13820\&.0 13820\&.0 194 81 2\&.938 3\&.863\fP 547 .fi 548 .nf 549 \f3\fP 550 .fi 551 .sp 552 .SS MONITOR\ INSTRUMENTATION\ FOR\ A\ REMOTE\ JVM 553 This example attaches to lvmid 40496 on the system named remote\&.domain using the \f3-gcutil\fR option, with samples taken every second indefinitely\&. 554 .PP 555 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 \f3rmiregistry\fR command on \f3remote\&.domain\fR that is bound to the default port of the \f3rmiregistry\fR command (port 1099)\&. 556 .sp 557 .nf 558 \f3jstat \-gcutil 40496@remote\&.domain 1000\fP 559 .fi 560 .nf 561 \f3\fI\&.\&.\&. output omitted\fR\fP 562 .fi 563 .nf 564 \f3\fP 565 .fi 566 .sp 567 .SH SEE\ ALSO 568 .TP 0.2i 569 \(bu 570 java(1) 571 .TP 0.2i 572 \(bu 573 jps(1) 574 .TP 0.2i 575 \(bu 576 jstatd(1) 577 .TP 0.2i 578 \(bu 579 rmiregistry(1) 580 .RE 581 .br 582 'pl 8.5i 583 'bp