biotop(8)

NAME
biotop - Block device (disk) I/O by process top.

SYNOPSIS
biotop [-h] [-C] [-r MAXROWS] [interval] [count]

DESCRIPTION
This is top for disks. This traces block device I/O (disk I/O), and prints a per-process summary every interval (by default, 1 second). The summary is sorted on the top disk consumers by throughput (Kbytes). The PID and process name shown are measured from when the I/O was first created, which usually identifies the responsible process. For efficiency, this uses in-kernel eBPF maps to cache process details (PID and comm) by I/O request, as well as a starting timestamp for calculating I/O latency, and the final summary. This works by tracing various kernel blk_*() functions using dynamic tracing, and will need updating to match any changes to these functions. Since this uses BPF, only the root user can use this tool.

REQUIREMENTS
CONFIG_BPF and bcc.

OPTIONS

-C  Don't clear the screen.

-r MAXROWS
    Maximum number of rows to print. Default is 20.

-p PID
    Trace this PID only.

interval
    Interval between updates, seconds.

count
    Number of interval summaries.

EXAMPLES

Summarize block device I/O by process, 1 second screen refresh:
    # biotop

Don't clear the screen:
    # biotop -C

5 second summaries, 10 times only:
    # biotop 5 10

FIELDS

loadavg:
    The contents of /proc/loadavg

PID Cached process ID, if present. This usually (but isn't guaranteed) to identify the responsible process for the I/O.

COMM
    Cached process name, if present. This usually (but isn't guaranteed) to identify the responsible process for the I/O.

D   Direction: R == read, W == write. This is a simplification.

MAJ Major device number.

MIN Minor device number.

DISK
    Disk device name.

I/O Number of I/O during the interval.

Kbytes
    Total Kbytes for these I/O, during the interval.

AVGms
    Average time for the I/O (latency) from the issue to the device, to its completion, in milliseconds.

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 negligible. For high IOPS storage systems, test and quantify 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
Brendan Gregg

INSPIRATION
top(1) by William LeFebvre

SEE ALSO
biosnoop(8), biolatency(8), iostat(1)