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LAT_SYSCALL(8)			    LMBENCH			LAT_SYSCALL(8)

NAME
       lat_syscall - time simple entry into the	operating system

SYNOPSIS
       lat_syscall  [ -P _parallelism_ ] [ -W _warmups_	] [ -N _repetitions_ ]
       null|read|write|stat|fstat|open [ file ]

DESCRIPTION
       null   measures how long	it takes to do getppid().  We chose  getppid()
	      because  in  all	UNIX  variants	we are aware of, it requires a
	      round-trip to/from kernel	space and the actual work required in-
	      side the kernel is small and bounded.

       read   measures	how  long  it  takes  to read one byte from /dev/zero.
	      Note that	some operating systems do not support /dev/zero.

       write  times how	long it	takes to write one byte	to /dev/null.  This is
	      useful  as  a  lower bound cost on anything that has to interact
	      with the operating system.

       stat   measures how long	it takes to stat() a file whose	inode  is  al-
	      ready cached.

       fstat  measures	how  long it takes to fstat() an open file whose inode
	      is already cached.

       open   measures how long	it takes to open() and then close() a file.

OUTPUT
       Output format is

       Null syscall: 67	microseconds

ACKNOWLEDGEMENT
       Funding for the development of this tool	was provided by	Sun  Microsys-
       tems Computer Corporation.

SEE ALSO
       lmbench(8).

AUTHOR
       Carl Staelin and	Larry McVoy

       Comments, suggestions, and bug reports are always welcome.

(c)1994	Larry McVoy		    $Date$			LAT_SYSCALL(8)

NAME | SYNOPSIS | DESCRIPTION | OUTPUT | ACKNOWLEDGEMENT | SEE ALSO | AUTHOR

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