Provided by: bpfcc-tools_0.5.0-5ubuntu1_all bug

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)