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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.atom(3), pmc.core(3), pmc.core2(3), pmc.iaf(3), pmc.k7(3),
pmc.k8(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 14.0-RELEASE-p6 October 4, 2008 FreeBSD 14.0-RELEASE-p6