Manual: vfsstat-bpfcc

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

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

SYNOPSIS
       vfsstat [interval [count]]

DESCRIPTION
       This traces some common VFS calls and prints per-second summaries. This can be useful for general workload character‐
       ization, and looking for patterns in operation usage over time.

       This works by tracing some kernel vfs functions using dynamic tracing, and will need updating to match any changes to
       these  functions.  Edit	the  script to customize which functions are traced. Also see vfscount, which is more easily
       customized to trace multiple functions.

       Since this uses BPF, only the root user can use this tool.

REQUIREMENTS
       CONFIG_BPF and bcc.

EXAMPLES
       Print summaries each second:
	      # vfsstat

       Print output every five seconds, three times:
	      # vfsstat 5 3

FIELDS
       READ/s Number of vfs_read() calls as a per-second average.

       WRITE/s
	      Number of vfs_write() calls as a per-second average.

       CREATE/s
	      Number of vfs_create() calls as a per-second average.

       OPEN/s Number of vfs_open() calls as a per-second average.

       FSYNC/s
	      Number of vfs_fsync() calls as a per-second average.

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

SOURCE
       This is from bcc.

	      https://github.com/iovisor/bcc

       Also look in the bcc distribution for a companion _examples.txt file containing example usage, output, and commentary
       for this tool.

OS
       Linux

STABILITY
       Unstable - in development.

AUTHOR
       Brendan Gregg

SEE ALSO
       vfscount(8)

USER COMMANDS						 2015-08-18						  vfsstat(8)