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 biosnoop.bt(8).

       This uses the tracepoint:block:block_rq_issue tracepoint,  and  is  a  simple  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 negligible. 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)