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| .TH "JFR" "1" "2020" "JDK 14" "JDK Commands" |
| .hy |
| .SH NAME |
| .PP |
| jfr \- parse and print Flight Recorder files |
| .SH SYNOPSIS |
| .PP |
| To print the contents of a flight recording to standard out: |
| .PP |
| \f[CB]jfr\f[R] \f[CB]print\f[R] [\f[I]options\f[R]] \f[I]file\f[R] |
| .PP |
| To print metadata information about flight recording events: |
| .PP |
| \f[CB]jfr\f[R] \f[CB]metadata\f[R] \f[I]file\f[R] |
| .PP |
| To assemble chunk files into a flight recording file: |
| .PP |
| \f[CB]jfr\f[R] \f[CB]assemble\f[R] \f[I]repository\f[R] \f[I]file\f[R] |
| .PP |
| To disassemble a flight recording file into chunk files: |
| .PP |
| \f[CB]jfr\f[R] \f[CB]disassmble\f[R] [\f[I]options\f[R]] \f[I]file\f[R] |
| .PP |
| To view the summary statistics for a flight recording file: |
| .PP |
| \f[CB]jfr\f[R] \f[CB]summary\f[R] \f[I]file\f[R] |
| .TP |
| .B \f[I]options\f[R] |
| Optional: Specifies command\-line options separated by spaces. |
| See the individual subcomponent sections for descriptions of the |
| available options. |
| .RS |
| .RE |
| .TP |
| .B \f[I]file\f[R] |
| Specifies the name of the target flight recording file |
| (\f[CB]\&.jfr\f[R]). |
| .RS |
| .RE |
| .TP |
| .B \f[I]repository\f[R] |
| Specifies the location of the chunk files which are to be assembled into |
| a flight recording. |
| .RS |
| .RE |
| .SH DESCRIPTION |
| .PP |
| The \f[CB]jfr\f[R] command provides a tool for interacting with flight |
| recorder files (\f[CB]\&.jfr\f[R]). |
| The main function is to filter, summarize and output flight recording |
| files into human readable format. |
| There is also support for merging and splitting recording files. |
| .PP |
| Flight recording files are created and saved as binary formatted files. |
| Having a tool that can extract the contents from a flight recording and |
| manipulate the contents and translate them into human readable format |
| helps developers to debug performance issues with Java applications. |
| .SS Subcommands |
| .PP |
| The \f[CB]jfr\f[R] command has several subcommands: |
| .IP \[bu] 2 |
| \f[CB]print\f[R] |
| .IP \[bu] 2 |
| \f[CB]summary\f[R] |
| .IP \[bu] 2 |
| \f[CB]assemble\f[R] |
| .IP \[bu] 2 |
| \f[CB]disassemble\f[R] |
| .IP \[bu] 2 |
| \f[CB]metadata\f[R] |
| .SS \f[CB]jfr\ print\f[R] subcommand |
| .PP |
| Use \f[CB]jfr\ print\f[R] to print the contents of a flight recording file |
| to standard out. |
| The syntax is: |
| .PP |
| \f[CB]jfr\ print\f[R] [\f[CB]\-\-xml\f[R]|\f[CB]\-\-json\f[R]] |
| [\f[CB]\-\-categories\f[R] <\f[I]filters\f[R]>] [\f[CB]\-\-events\f[R] |
| <\f[I]filters\f[R]>] [\f[CB]\-\-stack\-depth\f[R] <\f[I]depth\f[R]>] |
| <\f[I]file\f[R]> |
| .PP |
| where: |
| .TP |
| .B \f[CB]\-\-xml\f[R] |
| Print the recording in XML format |
| .RS |
| .RE |
| .TP |
| .B \f[CB]\-\-json\f[R] |
| Print the recording in JSON format |
| .RS |
| .RE |
| .TP |
| .B \f[CB]\-\-categories\f[R] <\f[I]filters\f[R]> |
| Select events matching a category name. |
| The filter is a comma\-separated list of names, simple and/or qualified, |
| and/or quoted glob patterns |
| .RS |
| .RE |
| .TP |
| .B \f[CB]\-\-events\f[R] <\f[I]filters\f[R]> |
| Select events matching an event name. |
| The filter is a comma\-separated list of names, simple and/or qualified, |
| and/or quoted glob patterns |
| .RS |
| .RE |
| .TP |
| .B \f[CB]\-\-stack\-depth\f[R] <\f[I]depth\f[R]> |
| Number of frames in stack traces, by default 5 |
| .RS |
| .RE |
| .TP |
| .B <\f[I]file\f[R]> |
| Location of the recording file (\f[CB]\&.jfr\f[R]) |
| .RS |
| .RE |
| .PP |
| The default format for printing the contents of the flight recording |
| file is human readable form unless either \f[CB]xml\f[R] or \f[CB]json\f[R] |
| is specified. |
| These options provide machine\-readable output that can be further |
| parsed or processed by user created scripts. |
| .PP |
| Use \f[CB]jfr\ \-\-help\ print\f[R] to see example usage of filters. |
| .PP |
| To reduce the amount of data displayed, it is possible to filter out |
| events or categories of events. |
| The filter operates on the symbolic name of an event, set by using the |
| \f[CB]\@Name\f[R] annotation, or the category name, set by using the |
| \f[CB]\@Category\f[R] annotation. |
| If multiple filters are used, events from both filters will be included. |
| If no filter is used, all the events will be printed. |
| If a combination of a category filter and event filter is used, the |
| selected events will be the union of the two filters. |
| .PP |
| For example, to show all GC events and the CPULoad event, the following |
| command could be used: |
| .PP |
| \f[CB]jfr\ print\ \-\-categories\ GC\ \-\-events\ CPULoad\ recording.jfr\f[R] |
| .PP |
| Event values are formatted according to the content types that are being |
| used. |
| For example, a field with the \f[CB]jdk.jfr.Percentage\f[R] annotation |
| that has the value 0.52 is formatted as 52%. |
| .PP |
| Stack traces are by default truncated to 5 frames, but the number can be |
| increased/decreased using the \f[CB]\-\-stack\-depth\f[R] command\-line |
| option. |
| .SS \f[CB]jfr\ summary\f[R] subcommand |
| .PP |
| Use \f[CB]jfr\ summary\f[R] to print statistics for a recording. |
| For example, a summary can illustrate the number of recorded events and |
| how much disk space they used. |
| This is useful for troubleshooting and understanding the impact of event |
| settings. |
| .PP |
| The syntax is: |
| .PP |
| \f[CB]jfr\ summary\f[R] <\f[I]file\f[R]> |
| .PP |
| where: |
| .TP |
| .B <\f[I]file\f[R]> |
| Location of the flight recording file (\f[CB]\&.jfr\f[R]) |
| .RS |
| .RE |
| .SS \f[CB]jfr\ metadata\f[R] subcommand |
| .PP |
| Use \f[CB]jfr\ metadata\f[R] to view information about events, such as |
| event names, categories and field layout within a flight recording file. |
| The syntax is: |
| .PP |
| \f[CB]jfr\ metadata\f[R] <\f[I]file\f[R]> |
| .PP |
| where: |
| .TP |
| .B <\f[I]file\f[R]> |
| Location of the flight recording file (\f[CB]\&.jfr\f[R]) |
| .RS |
| .RE |
| .SS jfr \f[CB]assemble\f[R] subcommand |
| .PP |
| Use jfr \f[CB]assemble\f[R] to assemble chunk files into a recording file. |
| .PP |
| The syntax is: |
| .PP |
| \f[CB]jfr\ assemble\f[R] <\f[I]repository\f[R]> <\f[I]file\f[R]> |
| .PP |
| where: |
| .TP |
| .B <\f[I]repository\f[R]> |
| Directory where the repository containing chunk files is located |
| .RS |
| .RE |
| .TP |
| .B <\f[I]file\f[R]> |
| Location of the flight recording file (\f[CB]\&.jfr\f[R]) |
| .RS |
| .RE |
| .PP |
| Flight recording information is written in chunks. |
| A chunk contains all of the information necessary for parsing. |
| A chunk typically contains events useful for troubleshooting. |
| If a JVM should crash, these chunks can be recovered and used to create |
| a flight recording file using this \f[CB]jfr\ assemble\f[R] command. |
| These chunk files are concatenated in chronological order and chunk |
| files that are not finished (.part) are excluded. |
| .SS \f[CB]jfr\ disassemble\f[R] subcommand |
| .PP |
| Use \f[CB]jfr\ disassemble\f[R] to decompose a flight recording file into |
| its chunk file pieces. |
| The syntax is: |
| .PP |
| \f[CB]jfr\ disassemble\f[R] [\f[CB]\-\-max\-chunks\f[R] <\f[I]chunks\f[R]>] |
| [\f[CB]\-\-output\f[R] <\f[I]directory\f[R]>] <\f[I]file\f[R]> |
| .PP |
| where: |
| .TP |
| .B \f[CB]\-\-output\f[R] <\f[I]directory\f[R]> |
| The location to write the disassembled file, by default the current |
| directory |
| .RS |
| .RE |
| .TP |
| .B \f[CB]\-\-max\-chunks\f[R] <\f[I]chunks\f[R]> |
| Maximum number of chunks per file, by default 5. |
| The chunk size varies, but is typically around 15 MB. |
| .RS |
| .RE |
| .TP |
| .B \f[CB]\-\-max\-size\f[R] <\f[I]size\f[R]> |
| Maximum number of bytes per file. |
| .RS |
| .RE |
| .TP |
| .B <\f[I]file\f[R]> |
| Location of the flight recording file (\f[CB]\&.jfr\f[R]) |
| .RS |
| .RE |
| .PP |
| This function can be useful for repairing a broken file by removing the |
| faulty chunk. |
| It can also be used to reduce the size of a file that is too large to |
| transfer. |
| The resulting chunk files are named \f[CB]myfile_1.jfr\f[R], |
| \f[CB]myfile_2.jfr\f[R], etc. |
| If needed, the resulting file names will be padded with zeros to |
| preserve chronological order. |
| For example, the chunk file name is \f[CB]myfile_001.jfr\f[R] if the |
| recording consists of more than 100 chunks. |
| .SS jfr version and help subcommands |
| .PP |
| Use \f[CB]jfr\ \-\-version\f[R] or \f[CB]jfr\ version\f[R] to view the |
| version string information for this jfr command. |
| .PP |
| To get help on any of the jfr subcommands, use: |
| .PP |
| \f[CB]jfr\ <\-\-help|help>\f[R] [\f[I]subcommand\f[R]] |
| .PP |
| where: |
| .PP |
| [\f[I]subcommand\f[R]] is any of: |
| .IP \[bu] 2 |
| \f[CB]print\f[R] |
| .IP \[bu] 2 |
| \f[CB]metadata\f[R] |
| .IP \[bu] 2 |
| \f[CB]summary\f[R] |
| .IP \[bu] 2 |
| \f[CB]assemble\f[R] |
| .IP \[bu] 2 |
| \f[CB]disassemble\f[R] |
