NAME

       swapin - Count swapins by process. Uses BCC/eBPF.

SYNOPSIS

       swapin

       -h, --help
              show this help message and exit

       -T, --notime
              do not show the timestamp (HH:MM:SS)

DESCRIPTION

       This  tool  counts swapins by process, to show which process is affected by swapping (if swap devices are
       in use). This can explain a significant source of application latency, if it has began  swapping  due  to
       memory pressure on the system.

       This  works  by  tracing the swap_readpage() kernel function using dynamic instrumentation. This tool may
       need maintenance to keep working if that function changes in later kernels.

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

REQUIREMENTS

       CONFIG_BPF and BCC.

EXAMPLES

       Count swapins by process, showing per-second summaries.
              # swapin

FIELDS

       1st    The process name.

       2nd    The process ID.

       3rd    The count of swapins during that interval.

OVERHEAD

       The rate of swapins should be low (bounded by swapin device IOPS), such that the overhead of this tool is
       expected to be negligible.

SOURCE

       This  originated  as  a  bpftrace tool from the book "BPF Performance Tools", published by Addison Wesley
       (2019):

              http://www.brendangregg.com/bpf-performance-tools-book.html

       See the book for more documentation on this tool.

       This version is in the BCC repository:

              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

       swapon(8)