NAME

       statsnoop - Trace stat() syscalls. Uses Linux eBPF/bcc.

SYNOPSIS

       statsnoop [-h] [-t] [-x] [-p PID]

DESCRIPTION

       statsnoop  traces the different stat() syscalls, showing which processes are attempting to
       read information about which files. This can be useful for  determining  the  location  of
       config  and log files, or for troubleshooting applications that are failing, especially on
       startup.

       This works by tracing various kernel sys_stat() functions using dynamic tracing, and  will
       need updating to match any changes to these functions.

       This  makes  use  of a Linux 4.4 feature (bpf_perf_event_output()); for kernels older than
       4.4, see the version under tools/old, which uses an older mechanism.

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

REQUIREMENTS

       CONFIG_BPF and bcc.

OPTIONS

       -h     Print usage message.

       -t     Include a timestamp column: in seconds since the first event, with decimal places.

       -x     Only print failed stats.

       -p PID Trace this process ID only (filtered in-kernel).

EXAMPLES

       Trace all stat() syscalls:
              # statsnoop

       Trace all stat() syscalls, and include timestamps:
              # statsnoop -t

       Trace only stat() syscalls that failed:
              # statsnoop -x

       Trace PID 181 only:
              # statsnoop -p 181

FIELDS

       TIME(s)
              Time of the call, in seconds.

       PID    Process ID

       COMM   Process name

       FD     File descriptor (if success), or -1 (if failed)

       ERR    Error number (see the system's errno.h)

       PATH   Open path

OVERHEAD

       This traces the kernel stat function and prints output for each event. As the rate of this
       is  generally  expected  to  be  low  (<  1000/s),  the  overhead  is  also expected to be
       negligible. If you have an application that is calling a high rate of stat()s,  then  test
       and understand overhead before use.

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

       opensnoop(1)