xref: /aosp_15_r20/external/bcc/tools/filelife_example.txt (revision 387f9dfdfa2baef462e92476d413c7bc2470293e)

Demonstrations of filelife, the Linux eBPF/bcc version.


filelife traces short-lived files: those that have been created and then
deleted while tracing. For example:

# ./filelife
TIME     PID    COMM             AGE(s)  FILE
05:57:59 8556   gcc              0.04    ccCB5EDe.s
05:57:59 8560   rm               0.02    .entry_64.o.d
05:57:59 8563   gcc              0.02    cc5UFHXf.s
05:57:59 8567   rm               0.01    .thunk_64.o.d
05:57:59 8578   rm               0.02    .syscall_64.o.d
05:58:00 8589   rm               0.03    .common.o.d
05:58:00 8596   rm               0.01    .8592.tmp
05:58:00 8601   rm               0.01    .8597.tmp
05:58:00 8606   rm               0.01    .8602.tmp
05:58:00 8639   rm               0.02    .vma.o.d
05:58:00 8650   rm               0.02    .vdso32-setup.o.d
05:58:00 8656   rm               0.00    .vdso.lds.d
05:58:00 8659   gcc              0.01    ccveeJAz.s
05:58:00 8663   rm               0.01    .vdso-note.o.d
05:58:00 8674   rm               0.02    .vclock_gettime.o.d
05:58:01 8684   rm               0.01    .vgetcpu.o.d
05:58:01 8690   collect2         0.00    ccvKMxdm.ld

This has caught short-lived files that were created during a Linux kernel
build. The PID shows the process ID that finally deleted the file, and COMM
is its process name. The AGE(s) column shows the age of the file, in seconds,
when it was deleted. These are all short-lived, and existed for less than
one tenth of a second.

Creating, populating, and then deleting files as part of another process can
be an inefficient method of inter-process communication. It can cause disk I/O
as files are closed and their file descriptors flushed, only later to be
deleted. As such, short-lived files can be a target of performance
optimizations.

USAGE message:

# ./filelife -h
usage: filelife [-h] [-p PID]

Trace stat() syscalls

optional arguments:
  -h, --help         show this help message and exit
  -p PID, --pid PID  trace this PID only

examples:
    ./filelife           # trace all stat() syscalls
    ./filelife -p 181    # only trace PID 181