freebsd-skq/usr.sbin/pstat/pstat.8
Ed Schouten bc093719ca Integrate the new MPSAFE TTY layer to the FreeBSD operating system.
The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:

- Improved driver model:

  The old TTY layer has a driver model that is not abstract enough to
  make it friendly to use. A good example is the output path, where the
  device drivers directly access the output buffers. This means that an
  in-kernel PPP implementation must always convert network buffers into
  TTY buffers.

  If a PPP implementation would be built on top of the new TTY layer
  (still needs a hooks layer, though), it would allow the PPP
  implementation to directly hand the data to the TTY driver.

- Improved hotplugging:

  With the old TTY layer, it isn't entirely safe to destroy TTY's from
  the system. This implementation has a two-step destructing design,
  where the driver first abandons the TTY. After all threads have left
  the TTY, the TTY layer calls a routine in the driver, which can be
  used to free resources (unit numbers, etc).

  The pts(4) driver also implements this feature, which means
  posix_openpt() will now return PTY's that are created on the fly.

- Improved performance:

  One of the major improvements is the per-TTY mutex, which is expected
  to improve scalability when compared to the old Giant locking.
  Another change is the unbuffered copying to userspace, which is both
  used on TTY device nodes and PTY masters.

Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.

Obtained from:		//depot/projects/mpsafetty/...
Approved by:		philip (ex-mentor)
Discussed:		on the lists, at BSDCan, at the DevSummit
Sponsored by:		Snow B.V., the Netherlands
dcons(4) fixed by:	kan
2008-08-20 08:31:58 +00:00

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Groff

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.\" @(#)pstat.8 8.5 (Berkeley) 5/13/94
.\" $FreeBSD$
.\"
.Dd August 20, 2008
.Dt PSTAT 8
.Os
.Sh NAME
.Nm pstat ,
.Nm swapinfo
.Nd display system data structures
.Sh SYNOPSIS
.Nm
.Op Fl Tfghkmnst
.Op Fl M Ar core Op Fl N Ar system
.Nm swapinfo
.Op Fl ghkm
.Op Fl M Ar core Op Fl N Ar system
.Sh DESCRIPTION
The
.Nm
utility displays open file entry, swap space utilization,
terminal state, and vnode data structures.
.Pp
If invoked as
.Nm swapinfo
the
.Fl s
option is implied, and only the
.Fl k , m , g ,
and
.Fl h
options are legal.
.Pp
If the
.Fl M
option is not specified, information is obtained from
the currently running kernel via the
.Xr sysctl 3
interface.
Otherwise, information is read from the specified core file,
using the name list from the specified kernel image (or from
the default image).
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl n
Print devices out by major/minor instead of name.
.It Fl h
.Dq Human-readable
output.
Use unit suffixes when printing swap partition sizes:
Byte, Kilobyte, Megabyte, Gigabyte, Terabyte and Petabyte.
.It Fl k
Print sizes in kilobytes, regardless of the setting of the
.Ev BLOCKSIZE
environment variable.
.It Fl m
Print sizes in megabytes, regardless of the setting of the
.Ev BLOCKSIZE
environment variable.
.It Fl g
Print sizes in gigabytes, regardless of the setting of the
.Ev BLOCKSIZE
environment variable.
.It Fl T
Print the number of used and free slots in several system tables.
This is useful for checking to see how large system tables have become
if the system is under heavy load.
.It Fl f
Print the open file table with these headings:
.Bl -tag -width indent
.It LOC
The core location of this table entry.
.It TYPE
The type of object the file table entry points to.
.It FLG
Miscellaneous state variables encoded thus:
.Pp
.Bl -tag -width indent -compact
.It R
open for reading
.It W
open for writing
.It A
open for appending
.It I
signal pgrp when data ready
.El
.It CNT
Number of processes that know this open file.
.It MSG
Number of messages outstanding for this file.
.It DATA
The location of the vnode table entry or socket structure for this file.
.It OFFSET
The file offset (see
.Xr lseek 2 ) .
.El
.It Fl s
Print information about swap space usage on all the
swap areas compiled into the kernel.
The first column is the device name of the partition.
The next column is
the total space available in the partition.
The
.Ar Used
column indicates the total blocks used so far; the
.Ar Available
column indicates how much space is remaining on each partition.
The
.Ar Capacity
reports the percentage of space used.
.Pp
If more than one partition is configured into the system, totals for all
of the statistics will be reported in the final line of the report.
.It Fl t
Print table for terminals
with these headings:
.Bl -tag -width indent
.It LINE
Device name.
.It INQ
Number of characters that can be stored in the input queue.
.It CAN
Number of characters in the input queue which can be read.
.It LIN
Number of characters in the input queue which cannot be read yet.
.It LOW
Low water mark for input.
.It OUTQ
Number of characters that can be stored in the output queue.
.It USE
Number of bytes in the output queue.
.It LOW
Low water mark for input.
.It COL
Calculated column position of terminal.
.It SESS
Kernel address of the session structure.
.It PGID
Process group for which this is the controlling terminal.
.It STATE
Miscellaneous state variables encoded thus:
.Pp
.Bl -tag -width indent -compact
.It I
init/lock-state device nodes present
.It C
callout device nodes present
.It O
opened
.It G
gone
.It B
busy in
.Xr open 2
.It Y
send SIGIO for input events
.It L
next character is literal
.It H
high watermark reached
.It X
open for exclusive use
.It S
output stopped (ixon flow control)
.It l
block mode input routine in use
.It Z
connection lost
.El
.Pp
The
.Ql i
and
.Ql o
characters refer to the previous character, to differentiate between
input and output.
.El
.It Fl M
Extract values associated with the name list from the specified core.
.It Fl N
If
.Fl M
is also specified,
extract the name list from the specified system instead of the default,
which is the kernel image the system has booted from.
.El
.Sh SEE ALSO
.Xr ps 1 ,
.Xr systat 1 ,
.Xr stat 2 ,
.Xr fs 5 ,
.Xr iostat 8 ,
.Xr vmstat 8
.Rs
.%T UNIX Implementation
.%A K. Thompson
.Re
.Sh HISTORY
The
.Nm
utility appeared in
.Bx 4.0 .
.Sh BUGS
Does not understand
.Tn NFS
swap servers.