NAME

       lat_pagefault - measure the cost of pagefaulting pages from a file

SYNOPSIS

       lat_pagefault  [  -P <parallelism> ] [ -W <warmups> ] [ -N <repetitions> ] file [ file....
       ]

DESCRIPTION

       lat_pagefault times how fast a page of a file can be faulted in.  The file is flushed from
       (local)  memory  by  using the msync() interface with the invalidate flag set.  (Note that
       NFS does not send this over the wire so this makes for a handy way to measure the cost  of
       going across the wire.)

       The  benchmark  maps  in  the entire file and the access pages backwards using a stride of
       256K kilobytes.

OUTPUT

       Output format is below; it prints the average cost of page faulting a page.

       Pagefaults on <file>: <d> usecs

BUGS

       Using a stride of 256K may be a bad idea because SCSI controllers may have  caches  bigger
       than that.

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_PAGEFAULT(8)