Manual browser: sysstat(1)

SYSTAT(1) General Commands Manual SYSTAT(1)


systatdisplay system statistics on a CRT


systat [-n] [-M core] [-N system] [-t turns] [-w wait] [display] [refresh-interval]


systat displays various system statistics in a screen oriented fashion using the curses screen display library, curses(3).

While systat is running the screen is usually divided into two windows (an exception is the vmstat display which uses the entire screen). The upper window depicts the current system load average. The information displayed in the lower window may vary, depending on user commands. The last line on the screen is reserved for user input and error messages.

By default systat displays the processes getting the largest percentage of the processor in the lower window. Other displays show more detailed process information, swap space usage, disk usage statistics (a la df(1)), disk I/O statistics (a la iostat(8)), virtual memory statistics (a la vmstat(1)), network ``mbuf'' utilization, and network connections (a la netstat(1)).

Input is interpreted at two different levels. A ``global'' command interpreter processes all keyboard input. If this command interpreter fails to recognize a command, the input line is passed to a per-display command interpreter. This allows each display to have certain display-specific commands.

Command line options:

-M core
Extract values associated with the name list from core instead of the default /dev/mem.
-N system
Extract the name list from system instead of the default /netbsd.
Do not resolve IP addresses into string hostnames (FQDNs) on netstat. It has the same effect as numbers subcommand in netstat.
-w wait
See refresh-interval.
-t turns
How many refreshes to show each screen in 'all' display mode.
The display argument expects to be one of: all, bufcache, df, inet.icmp, inet.ip, inet.tcp, inet.tcpsyn, inet6.ip6, iostat, mbufs, netstat, pigs, ps, swap, syscall or vmstat. These displays can also be requested interactively and are described in full detail below.
The refresh-interval specifies the screen refresh time interval in seconds. This is provided for backwards compatibility, and overrides the refresh-interval specified with the -w flag.

Certain characters cause immediate action by systat. These are

Refresh the screen.
Print the name of the current ``display'' being shown in the lower window and the refresh interval.
Stop systat.
?, h
Print the names of the available displays on the command line.
Move the cursor to the command line and interpret the input line typed as a command. While entering a command the current character erase, word erase, and line kill characters may be used.

The following commands are interpreted by the ``global'' command interpreter.

help key
Print the names of the available displays on the command line. It will print long names as “inet.*”. To print items under “inet”, give inet as key.
Print the load average over the past 1, 5, and 15 minutes on the command line.
Stop refreshing the screen.
[start] [number]
Start (continue) refreshing the screen. If a second, numeric, argument is provided it is interpreted as a refresh interval in seconds. Supplying only a number will set the refresh interval to this value.
Exit systat. (This may be abbreviated to q.)

The available displays are:

Cycle through all displays automatically. At each display, wait some refresh-turns, then switch to the next display. Duration of one refresh-turn is adjustable with the -w option, number of refresh-turns can be changed with the -t option.
Display, in the lower window, statistics about the file system buffers. Statistics for each file system that has active buffers include the number of buffers for that file system, the number of active kilobytes in those buffers and the total size of the buffers for that file system.
Lists disk usage statistics for all filesystems, including the available free space as well as a bar graph indicating the used capacity.

The following commands are specific to the df display:

Displays information for all filesystems, including kernfs, procfs and null-mounts.
Suppress information about procfs, kernfs and null-mounts (default).
Display ICMP statistics.
Display IPv4 and UDP statistics.
Display TCP statistics.
Display statistics about the TCP ``syncache''.
Display IPv6 statistics.
Display, in the lower window, statistics about processor use and disk throughput. Statistics on processor use appear as bar graphs of the amount of time executing in user mode (``user''), in user mode running low priority processes (``nice''), in system mode (``system''), and idle (``idle''). Statistics on disk throughput show, for each drive, kilobytes of data transferred, number of disk transactions performed, and time spent in disk accesses in milliseconds. This information may be displayed as bar graphs or as rows of numbers which scroll downward. Bar graphs are shown by default;

The following commands are specific to the iostat display; the minimum unambiguous prefix may be supplied.

Show the disk I/O statistics in numeric form. Values are displayed in numeric columns which scroll downward.
Show the disk I/O statistics in bar graph form (default).
Toggle the display of time in disk activity (the default is to not display time).
Show the read and write statistics combined (default).
Show the read and write statistics separately.
Display, in the lower window, the number of mbufs allocated for particular uses, i.e. data, socket structures, etc.
Display, in the lower window, network connections. By default, network servers awaiting requests are not displayed. Each address is displayed in the format ``host.port'', with each shown symbolically, when possible. It is possible to have addresses displayed numerically, limit the display to a set of ports, hosts, and/or protocols (the minimum unambiguous prefix may be supplied):

Toggle the displaying of server processes awaiting requests (this is the equivalent of the -a flag to netstat 1).
Display network addresses numerically.
Display network addresses symbolically.
Display only network connections using the indicated protocol (currently either ``tcp'' or ``udp'').
ignore [items]
Do not display information about connections associated with the specified hosts or ports. Hosts and ports may be specified by name (``vangogh'', ``ftp''), or numerically. Host addresses use the Internet dot notation (``''). Multiple items may be specified with a single command by separating them with spaces.
display [items]
Display information about the connections associated with the specified hosts or ports. As for ignore, [items] may be names or numbers.
show [ports|hosts]
Show, on the command line, the currently selected protocols, hosts, and ports. Hosts and ports which are being ignored are prefixed with a `!'. If ports or hosts is supplied as an argument to show, then only the requested information will be displayed.
Reset the port, host, and protocol matching mechanisms to the default (any protocol, port, or host).
Display, in the lower window, those processes which are getting the largest portion of the processor (the default display). When less than 100% of the processor is scheduled to user processes, the remaining time is accounted to the ``idle'' process.
Display, in the lower window, the same information provided by the command ps(1) with the flags -aux.

The following command is specific to the ps display; the minimum unambiguous prefix may be supplied.

user name
Limit the list of processes displayed to those owned by user name. If name is specified as `+', processes owned by any user are displayed (default).
Show information about swap space usage on all the swap areas configured with swapctl(8). The first column is the device name of the partition. The next column is the total space available in the partition. The Used column indicates the total blocks used so far; the graph shows the percentage of space in use on each partition. If there are more than one swap partition in use, a total line is also shown. Areas known to the kernel, but not in use are shown as not available.
Show per system call statistics. The display consists of several columns of system call name and counts.

In order to stop entries moving around the screen too much, an infinite response filter is applied to the values before they are sorted.

The following commands are specific to the syscall display:

sort name
Sort display by the syscall name (default).
sort count
Sort display by the count of calls or time spent in the calls.
sort syscall
Sort display be syscall number.
show count
Show the number of times the system call has be called (default).
show time
Show the average amount of time (in arbitrary units) spent in a call of the syscall.
Take over the entire display and show a (rather crowded) compendium of statistics related to virtual memory usage, process scheduling, device interrupts, system name translation caching, disk I/O etc.

The upper left quadrant of the screen shows the number of users logged in and the load average over the last one, five, and fifteen minute intervals. Below this is a list of the average number of processes (over the last refresh interval) that are runnable (`r'), in page wait (`p'), in disk wait other than paging (`d'), sleeping (`s'). Below the queue length listing is a numerical listing and a bar graph showing the amount of system (shown as `='), user (shown as `>'), nice (shown as `-'), and idle time (shown as ` ').

To the right of the process statistics is a column that lists the average number of context switches (`Csw'), traps (`Trp'; includes page faults), system calls (`Sys'), interrupts (`Int'), network software interrupts (`Sof'), page faults (`Flt').

Below this are statistics on memory utilization. The first row of the table reports memory usage only among active processes, that is processes that have run in the previous twenty seconds. The second row reports on memory usage of all processes. The first column reports on the number of physical pages claimed by processes. The second column reports the number of pages of memory and swap. The third column gives the number of pages of free memory and swap.

Below the memory display are statistics on name translations. It lists the number of names translated in the previous interval, the number and percentage of the translations that were handled by the system wide name translation cache, and the number and percentage of the translations that were handled by the per process name translation cache.

At the bottom left is the disk usage display. It reports the number of seeks, transfers, number of kilobyte blocks transferred per second averaged over the refresh period of the display (by default, five seconds), and the time spent in disk accesses. If there are more than five disks, and the terminal window has more than 24 lines, the disks display will be flipped so that more of the disk statistics are visible.

Under the date in the upper right hand quadrant are statistics on paging and swapping activity. The first two columns report the average number of pages brought in and out per second over the last refresh interval due to page faults and the paging daemon. The third and fourth columns report the average number of pages brought in and out per second over the last refresh interval due to swap requests initiated by the scheduler. The first row of the display shows the average number of disk transfers per second over the last refresh interval; the second row of the display shows the average number of pages transferred per second over the last refresh interval.

Below the paging statistics is another columns of paging data. From top to bottom, these represent average numbers of copy on write faults (`cow'), object cache lookups (`objlk'), object cache hits (`objht'), pages zero filled on demand (`zfodw'), number zfod's created (`nzfod'), percentage of zfod's used (`%zfod'), number of kernel pages (`kern'), number of wired pages (`wire'), number of active pages (`act'), number of inactive pages (`inact'), number of free pages (`free'), pages freed by daemon (`daefr'), pages freed by exiting processes (`prcfr'), number of pages reactivated from freelist (`react'), scans in page out daemon (`scan'), revolutions of the hand (`hdrev'), and in-transit blocking page faults (`intrn'), per second over the refresh period. Note that the `%zfod' percentage is usually less than 100%, however it may exceed 100% if a large number of requests are actually used long after they were set up during a period when no new pages are being set up. Thus this figure is most interesting when observed over a long time period, such as from boot time (see below on getting such a display).

To the left of the column of paging statistics is a breakdown of the interrupts being handled by the system. At the top of the list is the total interrupts per second over the time interval. The rest of the column breaks down the total on a device by device basis. Only devices that have interrupted at least once since boot time are shown.

Commands to switch between displays may be abbreviated to the minimum unambiguous prefix; for example, ``io'' for ``iostat''. Certain information may be discarded when the screen size is insufficient for display. For example, on a machine with 10 drives the iostat bar graph displays only 3 drives on a 24 line terminal. When a bar graph would overflow the allotted screen space it is truncated and the actual value is printed ``over top'' of the bar.

The following commands are common to each display which shows information about disk drives. These commands are used to select a set of drives to report on, should your system have more drives configured than can normally be displayed on the screen. Drives may be specified as drive names or as patterns specified in the notation described by fnmatch(3).

display [drives]
Display information about the drives indicated. Multiple drives may be specified, separated by spaces.
ignore [drives]
Do not display information about the drives indicated. Multiple drives may be specified, separated by spaces.
drives [drives]
With no arguments, display a list of available drives. With arguments, replace the list of currently displayed drives with the ones specified.

The following commands are specific to the inet.*, inet6.*, syscall and vmstat displays; the minimum unambiguous prefix may be supplied.

Display cumulative statistics since the system was booted.
Display statistics as a running total from the point this command is given.
Display statistics averaged over the refresh interval (the default).
Reset running statistics to zero.


For the namelist.
For information in main memory.
For host names.
For network names.
For port names.


Much of the information that systat vmstat uses is obtained from struct vmmeter cnt.


The systat program appeared in 4.3BSD.


Consumes CPU resources and thus may skew statistics.

Certain displays presume a minimum of 80 characters per line.

The vmstat display looks out of place because it is (it was added in as a separate display from what used to be a different program).

October 19, 2012 NetBSD 7.0