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lat_pagefault - measure the cost of pagefaulting pages from a file
lat_pagefault [ -P <parallelism> ] [ -W <warmups> ] [ -N <repetitions> ]
file [ file.... ]
lat_pagefault times how fast a page of a file
can be faulted in. The file is flushed from (local) memory by using the
CBmsync() 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 format
is below; it prints the average cost of page faulting a page.
Pagefaults
on <file>: <d> usecs
Using a stride of 256K may be a bad idea because SCSI
controllers may have caches bigger than that.
Funding for
the development of this tool was provided by Sun Microsystems Computer
Corporation.
lmbench(8)
.
Carl Staelin and Larry McVoy
Comments,
suggestions, and bug reports are always welcome.
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