bcc-javaobjnew(8)

1uobjnew(8)                  System Manager's Manual                 uobjnew(8)
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NAME

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

10       cobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval]
11       javaobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval]
12       rubyobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval]
13       tclobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v] pid [interval]
14       uobjnew [-h] [-C TOP_COUNT] [-S TOP_SIZE] [-v]  [-l  {c,java,ruby,tcl}]
15       pid [interval]
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DESCRIPTION

18       uobjnew  traces  object  allocations in high-level languages (including
19       "malloc") and prints summaries of the most frequently  allocated  types
20       by number of objects or number of bytes.
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22       This  tool relies on USDT probes embedded in many high-level languages,
23       such as C, Java, Ruby, and Tcl. It requires a runtime instrumented with
24       these  probes, which in some cases requires building from source with a
25       USDT-specific flag, such as "--enable-dtrace" or  "--with-dtrace".  For
26       Java,  the  Java  process  must be started with the "-XX:+ExtendedDTra‐
27       ceProbes" flag.
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29       Since this uses BPF, only the root user can use this tool.
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REQUIREMENTS

32       CONFIG_BPF and bcc.
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OPTIONS

35       -C TOP_COUNT
36              Print the top object types sorted by number of instances.
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38       -S TOP_SIZE
39              Print the top object types sorted by size.
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41       -v     Print the resulting BPF program, for debugging purposes.
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43       {c,java,ruby,tcl}
44              The language to trace.
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46       pid    The process id to trace.
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48       interval
49              Wait this many seconds and then print the summary and  exit.  By
50              default, wait for Ctrl+C to exit.
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EXAMPLES

53       Trace object allocations in a Ruby process:
54              # uobjnew ruby 148
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56       Trace  object  allocations  from "malloc" and print the top 10 by total
57       size:
58              # uobjnew -S 10 c 1788
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FIELDS

61       TYPE   The object type being allocated. For C  (malloc),  this  is  the
62              block size.
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64       ALLOCS The number of objects allocated.
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66       BYTES  The number of bytes allocated.
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OVERHEAD

69       Object allocation events are quite frequent, and therefore the overhead
70       from running this tool can be considerable. Use with caution  and  make
71       sure  to  test  before  using in a production environment. Nonetheless,
72       even thousands of allocations per second will likely produce a  reason‐
73       able overhead when investigating a problem.
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SOURCE

76       This is from bcc.
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78              https://github.com/iovisor/bcc
79
80       Also  look  in  the  bcc distribution for a companion _example.txt file
81       containing example usage, output, and commentary for this tool.
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OS

84       Linux
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STABILITY

87       Unstable - in development.
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AUTHOR

90       Sasha Goldshtein
91