uobjnew(8)

NAME
uobjnew, javaobjnew, rubyobjnew, cobjnew - Summarize object allocations in high-level languages.

SYNOPSIS
javaobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval]
rubyobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval]
cobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval]
uobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] [-l {java,ruby,c}] pid [interval]

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 Node, Java, Python, and Ruby. 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.

REQUIREMENTS
CONFIG_BPF and bcc.

OPTIONS

-C TOP_COUNT
    Print the top object types sorted by number of instances.

-S TOP_SIZE
    Print the top object types sorted by size.

-v  Print the resulting BPF program, for debugging purposes.

{java,ruby,c}
    The language to trace.

pid The process id to trace.

interval
    Wait this many seconds and then print the summary and exit. By default, wait for Ctrl+C to exit.

EXAMPLES

Trace object allocations in a Ruby process:
    # uobjnew ruby 148

Trace object allocations from "malloc" and print the top 10 by total size:
    # uobjnew -S 10 c 1788

FIELDS

TYPE
    The object type being allocated. For C (malloc), this is the block size.

ALLOCS
    The number of objects allocated.

BYTES
    The number of bytes allocated.

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.

SOURCE
This is from bcc.

    https://github.com/iovisor/bcc

Also look in the bcc distribution for a companion _example.txt file containing example usage, output, and commentary for this tool.

OS
Linux

STABILITY
Unstable - in development.

AUTHOR
Sasha Goldshtein

SEE ALSO
ustat(8), ugc(8), memleak(8)