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LINE(8)				    LMBENCH			       LINE(8)

NAME
       line - cache line size

SYNOPSIS
       line [ -M _len_ ] [ -W _warmups_	] [ -N _repetitions_ ]

DESCRIPTION
       line  tries  to	determine  the cache line size in bytes	of the largest
       cache which is smaller than len bytes.

       line creates pointer chains which access	the first word on  each	 cache
       line on a page (randomly	meandering through all the lines in a page be-
       fore jumping to the next	page).	It measures the	average	memory latency
       for  a  variety	of  line sizes,	starting with a	line size of one word.
       When it finds an	increase in the	average	latency	that is	 significantly
       larger  than the	latency	for the	smaller	line size then it assumes that
       it has found the	line size.

       This algorithm works because for	line sizes less	 than  the  true  line
       size,  at  least	 two line cache	lines fit in the space of a true cache
       line.  Since that cache line will be accessed twice, the	 first	access
       will  cause  an expensive cache miss, while the second access will be a
       cache hit.  Once	the line cache line is equal to	the  true  cache  line
       size, then all accesses will cause cache	misses.

BUGS
       line  is	 an  experimental benchmark, but it seems to work well on most
       systems.

SEE ALSO
       lmbench(8), tlb(8), cache(8), par_mem(8).

AUTHOR
       Carl Staelin and	Larry McVoy

       Comments, suggestions, and bug reports are always welcome.

(c)2000	Carl Staelin and Larry McVoy$Date$			       LINE(8)

NAME | SYNOPSIS | DESCRIPTION | BUGS | SEE ALSO | AUTHOR

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