NAME¶

bitesize - Summarize block device I/O size as a histogram - Linux eBPF/bcc.

SYNOPSIS¶

bitesize

DESCRIPTION¶

Show I/O distribution for requested block sizes, by process name.

This works by tracing block:block_rq_issue and prints a histogram of I/O size.

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

REQUIREMENTS¶

CONFIG_BPF and bcc.

EXAMPLES¶

Count I/O size per process until Ctrl-C is hit:

# bitesize

FIELDS¶

Kbtes

Size in kilobytes of range

count

How many I/O fell into this range

distribution

An ASCII bar chart to visualize the distribution (count column)

OVERHEAD¶

This traces a block I/O tracepoint to update a histogram, which is 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.

SOURCE¶

This is from bcc.

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¶

Allan McAleavy

SEE ALSO¶

https://github.com/brendangregg/systemtap-lwtools/blob/master/disk/bitesize-nd.stp