NAME

       syncsnoop.bt - Trace the sync() variety of syscalls. Uses bpftrace/eBPF.

SYNOPSIS

       syncsnoop.bt

DESCRIPTION

       syncsnoop  traces  calls to sync() syscalls (sync(), fsync(), msync(), etc), which flushes
       file system cache and buffers to  storage  devices.  These  calls  can  cause  performance
       perturbations,  and  it can be useful to know if they are happening, when they happen, and
       how frequently.

       This works by tracing the sync() variety of syscalls via tracepoints.

       This program is also a basic example of eBPF/bcc.

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

REQUIREMENTS

       CONFIG_BPF and bpftrace.

EXAMPLES

       Trace calls to sync() syscalls:
              # syncsnoop.bt

FIELDS

       TIME   A timestamp on the output, in "HH:MM:SS" format.

       PID    The process ID that was on-CPU during the event.

       COMM   The process name that was on-CPU during the event.

       EVENT  The tracepoint name for the sync event.

OVERHEAD

       This traces sync syscalls and prints output for  each  event.  As  the  rate  of  this  is
       generally expected to be low (<< 100/s), the overhead is also expected to be negligible.

SOURCE

       This is from bpftrace.

              https://github.com/iovisor/bpftrace

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

       This is a bpftrace version of the bcc tool of the same name.

              https://github.com/iovisor/bcc

OS

       Linux

STABILITY

       Unstable - in development.

AUTHOR

       Brendan Gregg

SEE ALSO

       iostat(1)