uobjnew(8) System Manager's Manual uobjnew(8)
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:+ExtendedDTra-
ceProbes" 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 reason-
able 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)
USER COMMANDS 2018-10-09 uobjnew(8)
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