bcc-uobjnew(8)

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

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

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

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

31       CONFIG_BPF and bcc.
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OPTIONS

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

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

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

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

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

83       Linux
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STABILITY

86       Unstable - in development.
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AUTHOR

89       Sasha Goldshtein
90