swapin(8) System Manager's Manual swapin(8)
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 signifi-
cant 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)
USER COMMANDS 2019-07-05 swapin(8)
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