---
name: "javaobjnew-bpfcc"
section: "8"
platform: "linux"
package: "bpfcc-tools"
version: "0.31.0+ds-7"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/javaobjnew-bpfcc"
---

# javaobjnew-bpfcc(8)

Summarize object allocations in high-level languages.

## NAME

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

## SYNOPSIS

**cobjnew \[-h\] \[-C TOP\_COUNT\] \[-S TOP\_SIZE\] \[-v\] pid \[interval\]**\
 **javaobjnew \[-h\] \[-C TOP\_COUNT\] \[-S TOP\_SIZE\] \[-v\] pid \[interval\]**\
 **rubyobjnew \[-h\] \[-C TOP\_COUNT\] \[-S TOP\_SIZE\] \[-v\] pid \[interval\]**\
 **tclobjnew \[-h\] \[-C TOP\_COUNT\] \[-S TOP\_SIZE\] \[-v\] pid \[interval\]**\
 **uobjnew \[-h\] \[-C TOP\_COUNT\] \[-S TOP\_SIZE\] \[-v\] \[-l {c,java,ruby,tcl}\] 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 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.

## 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.

- {c,java,ruby,tcl}

  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)](/ustat/8.md), [ugc(8)](/ugc/8.md), memleak(8)