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GET_CYCLECOUNT(9)	 BSD Kernel Developer's	Manual	     GET_CYCLECOUNT(9)

NAME
     get_cyclecount -- get the CPU's fast counter register contents

SYNOPSIS
     #include <sys/param.h>
     #include <sys/systm.h>
     #include <machine/cpu.h>

     uint64_t
     get_cyclecount(void);

DESCRIPTION
     The get_cyclecount() function uses	a register available in	most modern
     CPUs to return a value that is monotonically increasing inside each CPU.

     On	SMP systems, there will	be a number of separate	monotonic sequences,
     one for each CPU running.	The value in the SMP case is selected from one
     of	these sequences, dependent on which CPU	was scheduled to service the
     request.

     The speed and the maximum value of	each counter is	CPU-dependent.	Some
     CPUs (such	as the Intel 80486) do not have	such a register, so
     get_cyclecount() on these platforms returns a (monotonic) combination of
     numbers represented by the	structure returned by binuptime(9).

     The AMD64 and Intel 64 processors use the TSC register.

SEE ALSO
     binuptime(9)

HISTORY
     The get_cyclecount() function first appeared in FreeBSD 5.0.

AUTHORS
     This manual page was written by Mark Murray <markm@FreeBSD.org>.

BSD				March 15, 2011				   BSD

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | AUTHORS

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