Provided by: lmbench-doc_3.0-a7-1ubuntu1_all bug

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
              inside 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
              already 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
       Microsystems 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)