bcc-swapin(8)

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

6       swapin - Count swapins by process. Uses BCC/eBPF.
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SYNOPSIS

9       swapin
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11       -h, --help
12              show this help message and exit
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14       -T, --notime
15              do not show the timestamp (HH:MM:SS)
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DESCRIPTION

18       This  tool counts swapins by process, to show which process is affected
19       by swapping (if swap devices are in use). This can explain  a  signifi‐
20       cant  source  of  application  latency, if it has began swapping due to
21       memory pressure on the system.
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23       This works by tracing the swap_readpage() kernel function using dynamic
24       instrumentation. This tool may need maintenance to keep working if that
25       function changes in later kernels.
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27       Since this uses BPF, only the root user can use this tool.
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REQUIREMENTS

30       CONFIG_BPF and BCC.
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EXAMPLES

33       Count swapins by process, showing per-second summaries.
34              # swapin
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FIELDS

37       1st    The process name.
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39       2nd    The process ID.
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41       3rd    The count of swapins during that interval.
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OVERHEAD

44       The rate of swapins should be low (bounded by swapin device IOPS), such
45       that the overhead of this tool is expected to be negligible.
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SOURCE

48       This  originated  as  a  bpftrace  tool  from the book "BPF Performance
49       Tools", published by Addison Wesley (2019):
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51              http://www.brendangregg.com/bpf-performance-tools-book.html
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53       See the book for more documentation on this tool.
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55       This version is in the BCC repository:
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57              https://github.com/iovisor/bcc
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59       Also look in the bcc distribution for a  companion  _examples.txt  file
60       containing example usage, output, and commentary for this tool.
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OS

63       Linux
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STABILITY

66       Unstable - in development.
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AUTHOR

69       Brendan Gregg
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