glenda.party
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IOSTATS(4)                 Kernel Interfaces Manual                 IOSTATS(4)



NAME
       iostats - file system to measure I/O

SYNOPSIS
       iostats [ -d ] [ -f dbfile ] cmd [ args...  ]

DESCRIPTION
       Iostats  is  a  user-level file server that interposes itself between a
       program and the regular file server, which allows it to gather  statis‐
       tics  of  file system use at the level of the Plan 9 file system proto‐
       col, 9P.  After a program exits a report is printed on standard error.

       The report consists of three sections.  The first section  reports  the
       amount  of user data in read and write messages sent by the program and
       the average rate at which the data was transferred.  The protocol  line
       reports  the  amount of data sent as message headers, that is, protocol
       overhead.  The rpc line reports the total number of file system  trans‐
       actions.

       The  second section gives the number of messages, the fastest, slowest,
       and average turn around time and the amount of data involved with  each
       9P  message type.  The final section gives an I/O summary for each file
       used by the program in terms of opens, reads and writes.

       If the -d flag is present, a debugging log  including  all  traffic  is
       written to dbfile (default iostats.out).

EXAMPLE
       Display summary of file I/O incurred by ls(1):

              iostats ls

       Start a new shell, displaying all 9P traffic caused by the shell or its
       children:

              iostats -df /fd/1 rc

SOURCE
       /sys/src/cmd/iostats

SEE ALSO
       dup(3)

BUGS
       Poor clock resolution means that large amounts of I/O must be  done  to
       get accurate rate figures.

       Can  be fooled by programs that do fresh mounts outside its purview, or
       by the use of names of files with content  that  can  vary  by  process
       (e.g.,



                                                                    IOSTATS(4)