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 before 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)