bcc-vfsstat(8)

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

6       vfsstat - Statistics for some common VFS calls. Uses Linux eBPF/bcc.
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SYNOPSIS

9       vfsstat [interval [count]]
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DESCRIPTION

12       This traces some common VFS calls and prints per-second summaries. This
13       can be useful for general workload characterization,  and  looking  for
14       patterns in operation usage over time.
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16       This  works by tracing some kernel vfs functions using dynamic tracing,
17       and will need updating to match any changes to  these  functions.  Edit
18       the  script to customize which functions are traced. Also see vfscount,
19       which is more easily customized to trace multiple functions.
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21       Since this uses BPF, only the root user can use this tool.
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REQUIREMENTS

24       CONFIG_BPF and bcc.
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EXAMPLES

27       Print summaries each second:
28              # vfsstat
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30       Print output every five seconds, three times:
31              # vfsstat 5 3
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FIELDS

34       READ/s Number of vfs_read() calls as a per-second average.
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36       WRITE/s
37              Number of vfs_write() calls as a per-second average.
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39       CREATE/s
40              Number of vfs_create() calls as a per-second average.
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42       OPEN/s Number of vfs_open() calls as a per-second average.
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44       FSYNC/s
45              Number of vfs_fsync() calls as a per-second average.
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OVERHEAD

48       This traces  various  kernel  vfs  functions  and  maintains  in-kernel
49       counts,  which  are asynchronously copied to user-space. While the rate
50       of VFS operations can be very high  (>1M/sec),  this  is  a  relatively
51       efficient way to trace these events, and so the overhead is expected to
52       be small for normal workloads.  Measure in a test environment.
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SOURCE

55       This is from bcc.
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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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