| .TH uobjnew 8 "2018-10-09" "USER COMMANDS" |
| .SH NAME |
| uobjnew, cobjnew, javaobjnew, rubyobjnew, tclobjnew \- Summarize object allocations in |
| high-level languages. |
| .SH SYNOPSIS |
| .B cobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval] |
| .br |
| .B javaobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval] |
| .br |
| .B rubyobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval] |
| .br |
| .B tclobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval] |
| .br |
| .B uobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] [-l {c,java,ruby,tcl}] pid [interval] |
| .SH DESCRIPTION |
| uobjnew traces object allocations in high-level languages (including "malloc") |
| and prints summaries of the most frequently allocated types by number of |
| objects or number of bytes. |
| |
| This tool relies on USDT probes embedded in many high-level languages, such as |
| C, Java, Ruby, and Tcl. It requires a runtime instrumented with these |
| probes, which in some cases requires building from source with a USDT-specific |
| flag, such as "--enable-dtrace" or "--with-dtrace". For Java, the Java process |
| must be started with the "-XX:+ExtendedDTraceProbes" flag. |
| |
| Since this uses BPF, only the root user can use this tool. |
| .SH REQUIREMENTS |
| CONFIG_BPF and bcc. |
| .SH OPTIONS |
| .TP |
| \-C TOP_COUNT |
| Print the top object types sorted by number of instances. |
| .TP |
| \-S TOP_SIZE |
| Print the top object types sorted by size. |
| .TP |
| \-v |
| Print the resulting BPF program, for debugging purposes. |
| .TP |
| {c,java,ruby,tcl} |
| The language to trace. |
| .TP |
| pid |
| The process id to trace. |
| .TP |
| interval |
| Wait this many seconds and then print the summary and exit. By default, wait |
| for Ctrl+C to exit. |
| .SH EXAMPLES |
| .TP |
| Trace object allocations in a Ruby process: |
| # |
| .B uobjnew ruby 148 |
| .TP |
| Trace object allocations from "malloc" and print the top 10 by total size: |
| # |
| .B uobjnew -S 10 c 1788 |
| .SH FIELDS |
| .TP |
| TYPE |
| The object type being allocated. For C (malloc), this is the block size. |
| .TP |
| ALLOCS |
| The number of objects allocated. |
| .TP |
| BYTES |
| The number of bytes allocated. |
| .SH OVERHEAD |
| Object allocation events are quite frequent, and therefore the overhead from |
| running this tool can be considerable. Use with caution and make sure to |
| test before using in a production environment. Nonetheless, even thousands of |
| allocations per second will likely produce a reasonable overhead when |
| investigating a problem. |
| .SH SOURCE |
| This is from bcc. |
| .IP |
| https://github.com/iovisor/bcc |
| .PP |
| Also look in the bcc distribution for a companion _example.txt file containing |
| example usage, output, and commentary for this tool. |
| .SH OS |
| Linux |
| .SH STABILITY |
| Unstable - in development. |
| .SH AUTHOR |
| Sasha Goldshtein |
| .SH SEE ALSO |
| ustat(8), ugc(8), memleak(8) |
