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.TH bitesize 8 "2016-02-05" "USER COMMANDS"
.SH NAME
bitesize \- Summarize block device I/O size as a histogram \- Linux eBPF/bcc.
.SH SYNOPSIS
.B bitesize
.SH DESCRIPTION
Show I/O distribution for requested block sizes, by process name.
This works by tracing block I/O kernel functions using dynamic
tracing and prints a historgram of I/O size.
Since this uses BPF, only the root user can use this tool.
.SH REQUIREMENTS
CONFIG_BPF and bcc.
.SH EXAMPLES
.TP
Count I/O size per process until Ctrl-C is hit:
#
.B bitesize
.SH FIELDS
.TP
Kbtes
Size in kilobytes of range
.TP
count
How many I/O fell into this range
.TP
distribution
An ASCII bar chart to visualize the distribution (count column)
.SH OVERHEAD
This traces kernel block I/O functions to update a histgroam, which are
asynchronously copied to user-space. This method is very efficient, and
the overhead for most storage I/O rates (< 10k IOPS) should be negligible.
If you have a higher IOPS storage environment, test and quantify the overhead
before use.
.SH SOURCE
This is from bcc.
.IP
https://github.com/iovisor/bcc
.PP
Also look in the bcc distribution for a companion _examples.txt file containing
example usage, output, and commentary for this tool.
.SH OS
Linux
.SH STABILITY
Unstable - in development.
.SH AUTHOR
Allan McAleavy
.SH SEE ALSO
https://github.com/brendangregg/systemtap-lwtools/blob/master/disk/bitesize-nd.stp