PMC.TSC(3)             FreeBSD Library Functions Manual             PMC.TSC(3)

NAME

     pmc.tsc - measurements using the i386 timestamp counter

LIBRARY

     Performance Counters Library (libpmc, -lpmc)

SYNOPSIS

     #include <pmc.h>

DESCRIPTION

     In the i386 architecture, the timestamp counter is a monotonically non-
     decreasing counter that counts processor cycles.

     This counter may be selected specifying an event specifier "tsc" to
     pmc_allocate(3).  The TSC is a read-only counter that may only be
     allocated in system-wide counting mode.  The "tsc" event does not support
     further event qualifiers.

     Multiple processes are allowed to allocate the TSC.  Once allocated, the
     TSC may be read using the pmc_read() function, or by using the RDTSC
     instruction.

Event Name Aliases

     The alias "cycles" maps to the TSC.

SEE ALSO

     pmc(3), pmc.amd(3), pmc.atom(3), pmc.core(3), pmc.core2(3), pmc.iaf(3),
     pmc.soft(3), pmclog(3), hwpmc(4)

HISTORY

     The pmc library first appeared in FreeBSD 6.0.

AUTHORS

     The Performance Counters Library (libpmc, -lpmc) library was written by
     Joseph Koshy <jkoshy@FreeBSD.org>.

FreeBSD 15.1-STABLE-HBSD        October 4, 2008                     PMC.TSC(3)