bitesize(8)

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

6       bitesize.bt - Show disk I/O size as a histogram. Uses bpftrace/eBPF.
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SYNOPSIS

9       bitesize.bt
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DESCRIPTION

12       This  can  be  used  to  characterize  the distribution of block device
13       (disk) I/O sizes. To study block device I/O in more detail,  see  bios‐
14       noop(8).
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16       This uses the tracepoint:block:block_rq_issue tracepoint, and is a sim‐
17       ple example of bpftrace.
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19       Since this uses BPF, only the root user can use this tool.
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REQUIREMENTS

22       CONFIG_BPF and bpftrace.
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EXAMPLES

25       Trace block I/O and summarize as a histogram by process:
26              # bitesize.bt
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FIELDS

29       0th    A process name (shown in "@[...]") is printed  before  each  I/O
30              histogram.
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32       1st, 2nd
33              This  is  a  range of I/O sizes, in Kbytes (shown in "[...)" set
34              notation).
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36       3rd    A column showing the count of I/O in this range.
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38       4th    This is an ASCII histogram representing the count column.
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OVERHEAD

41       Since block device I/O  usually  has  a  relatively  low  frequency  (<
42       10,000/s), the overhead for this tool is expected to be low or negligi‐
43       ble. For high IOPS storage systems, test and quantify before use.
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SOURCE

46       This is from bpftrace.
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48              https://github.com/iovisor/bpftrace
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50       Also look in the bpftrace distribution for  a  companion  _examples.txt
51       file containing example usage, output, and commentary for this tool.
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53       This is a bpftrace version of the bcc tool of the same name.
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55              https://github.com/iovisor/bcc
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OS

58       Linux
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STABILITY

61       Unstable - in development.
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AUTHOR

64       Brendan Gregg
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