bitesize.bt(8) System Manager's Manual bitesize.bt(8)
NAME
bitesize.bt - Show disk I/O size as a histogram. Uses bpftrace/eBPF.
SYNOPSIS
bitesize.bt
DESCRIPTION
This can be used to characterize the distribution of block device
(disk) I/O sizes. To study block device I/O in more detail, see bios-
noop.bt(8).
This uses the tracepoint:block:block_rq_issue tracepoint, and is a sim-
ple example of bpftrace.
Since this uses BPF, only the root user can use this tool.
REQUIREMENTS
CONFIG_BPF and bpftrace.
EXAMPLES
Trace block I/O and summarize as a histogram by process:
# bitesize.bt
FIELDS
0th A process name (shown in "@[...]") is printed before each I/O
histogram.
1st, 2nd
This is a range of I/O sizes, in Kbytes (shown in "[...)" set
notation).
3rd A column showing the count of I/O in this range.
4th This is an ASCII histogram representing the count column.
OVERHEAD
Since block device I/O usually has a relatively low frequency (<
10,000/s), the overhead for this tool is expected to be low or negligi-
ble. For high IOPS storage systems, test and quantify before use.
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
biosnoop.bt(8)
USER COMMANDS 2018-09-07 bitesize.bt(8)
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