-.TH IOSTAT 1 ""
-.UC 4
-.SH NAME
-iostat \- report I/O statistics
-.SH SYNOPSIS
-.B iostat
-[ drives ]
-[ interval [ count ] ]
-.SH DESCRIPTION
-.I Iostat
-iteratively reports the number of characters read and written to terminals
-per second,
-and, for each disk, the number of transfers per second, kilobytes
-transferred per second,
-and the milliseconds per average seek.
-It also gives the percentage of time the system has
-spent in user mode, in user mode running low priority (niced) processes,
-in system mode, and idling.
-.PP
-To compute this information, for each disk, seeks and data transfer completions
-and number of words transferred are counted;
-for terminals collectively, the number
-of input and output characters are counted.
-Also, each sixtieth of a second,
-the state of each disk is examined
-and a tally is made if the disk is active.
-From these numbers and given the transfer rates
-of the devices it is possible to determine
-average seek times for each device.
-.PP
-The optional
-.I interval
-argument causes
-.I iostat
-to report once each
-.I interval
-seconds.
-The first report is for all time since a reboot and each
-subsequent report is for the last interval only.
-.PP
-The optional
-.I count
-argument restricts the number of reports.
-.PP
-If more than 4 disk drives are configured in the system,
-.I iostat
-displays only the first 4 drives, with priority given
-to Massbus disk drives (i.e. if both Unibus and Massbus
-drives are present and the total number of drives exceeds
-4, then some number of Unibus drives will not be displayed
-in favor of the Massbus drives). To force
-.I iostat
-to display specific drives, their names may be supplied on
-the command line.
-.SH FILES
-/dev/kmem
-.br
-/vmunix
-.SH SEE ALSO
-vmstat(1)
+.\" @(#)iostat.8 6.9 (Berkeley) %G%
+.\"
+.Dd
+.Dt IOSTAT 8
+.Os BSD 4
+.Sh NAME
+.Nm iostat
+.Nd report
+.Tn I/O
+statistics
+.Sh SYNOPSIS
+.Nm iostat
+.Op Fl c Ar count
+.Op Fl M Ar core
+.Op Fl N Ar system
+.Op Fl w Ar wait
+.Op Ar drives
+.Sh DESCRIPTION
+.Nm Iostat
+displays kernel
+.Tn I/O
+statistics on terminal, disk and cpu
+operations.
+.Pp
+The options are as follows:
+.Bl -tag -width flag
+.It Fl c
+Repeat the display
+.Ar count
+times.
+The first display is for the time since a reboot and each subsequent
+report is for the time period since the last display.
+If no
+.Ar wait
+interval is specified, the default is 1 second.
+.It Fl M
+Extract values associated with the name list from the specified core
+instead of the default
+.Dq Pa /dev/kmem .
+.It Fl N
+Extract the name list from the specified system instead of the default
+.Dq Pa /vmunix .
+.It Fl w
+Pause
+.Ar wait
+seconds between each display.
+If no repeat
+.Ar count
+is specified, the default is infinity.
+.El
+.Pp
+.Nm Iostat
+displays its information in the following format:
+.Bl -tag -width flag
+.It tty
+.Bl -tag -width indent -compact
+.It tin
+characters read from terminals
+.It tout
+characters written to terminals
+.El
+.It disks
+Disk operations (this field is system dependent).
+The header of the field is the disk name and unit number.
+If more than four disk drives are configured in the system,
+.Nm iostat
+displays only the first four drives.
+To force
+.Nm iostat
+to display specific drives, their names may be supplied on the command
+line.
+.Pp
+.Bl -tag -width indent -compact
+.It sps
+sectors transferred per second
+.It tps
+transfers per second
+.It msps
+milliseconds per average seek (including implied
+seeks and rotational latency)
+.El
+.It cpu
+.Bl -tag -width indent -compact
+.It \&us
+% of cpu time in user mode
+.It \&ni
+% of cpu time in user mode running niced processes
+.It \&sy
+% of cpu time in system mode
+.It \&id
+% of cpu time in idle mode
+.El
+.El
+.Sh FILES
+.Bl -tag -width /dev/kmem -compact
+.It Pa /vmunix
+Default kernel namelist.
+.It Pa /dev/kmem
+Default memory file.
+.El
+.Sh SEE ALSO
+.Xr fstat 1 ,
+.Xr netstat 1 ,
+.Xr nfsstat 1 ,
+.Xr \&ps 1 ,
+.Xr systat 1 ,
+.Xr vmstat 1 ,
+.Xr pstat 8
+.Pp
+The sections starting with ``Interpreting system activity'' in
+.%T "Installing and Operating 4.3BSD" .
projects / unix-history / blobdiff