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TLB(8)				    LMBENCH				TLB(8)

NAME
       tlb - TLB size and latency benchmark

SYNOPSIS
       tlb [ -L	<line size> ] [	-M <len> ] [ -W	<warmups> ] [ -N <repetitions>
       ]

DESCRIPTION
       tlb  tries  to  determine  the size, in pages, of the TLB.  The largest
       amount of memory	it will	examine	is len bytes.

       tlb compares the	memory latency for two different pointer chains.   The
       two  chains  occupy the same amount of cache space, but they stress the
       memory subsystem	differently.  The first	chain accesses	one  word  per
       page,  while the	second chain randomly jumps through all	the lines on a
       page before jumping to the next page.  When all of the pointers	reside
       in  the	cache  (which is the usual case), and all of the pages for the
       first chain reside in the TLB, then the average memory latencies	should
       be identical.  Assuming there is	a fixed	size TLB, then at  some	 point
       the  number of pages accessed by	the first page will be larger than the
       TLB.  At	this point the average latency for each	memory access for  the
       first chain will	be a cache hit plus some fraction of a TLB miss.

       Once  the  TLB  boundary	is located tlb reports the TLB miss latency as
       the TLB latency for twice as many pages as the TLB can hold.

BUGS
       tlb is an experimental benchmark, but it	seems to  work	well  on  most
       systems.	  However,  if	a processor has	a TLB hierarchy	tlb only finds
       the top level TLB.

SEE ALSO
       lmbench(8), line(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 M... $Date$				TLB(8)

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<https://man.freebsd.org/cgi/man.cgi?query=tlb&sektion=8&manpath=FreeBSD+Ports+15.0>

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