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Full Discussion: RDTSC use in C:
Top Forums Programming RDTSC use in C: Post 302241860 by calv on Tuesday 30th of September 2008 01:08:24 PM
Old 09-30-2008
rdtsc is not good for time measurement.

The problem is, that the CPU might throttle (with it does most of the time, when all processes are blocked), so a cpu clock might mean more time in that case. This is of course CPU and OS dependant.
 
CPUSET(3)						   BSD Library Functions Manual 						 CPUSET(3)

NAME
cpuset_create, cpuset_destroy, cpuset_zero, cpuset_set, cpuset_clr, cpuset_isset, cpuset_size -- dynamic CPU sets SYNOPSIS
#include <sched.h> cpuset_t * cpuset_create(void); void cpuset_destroy(cpuset_t *set); void cpuset_zero(cpuset_t *set); int cpuset_set(cpuid_t cpu, cpuset_t *set); int cpuset_clr(cpuid_t cpu, cpuset_t *set); int cpuset_isset(cpuid_t cpu, const cpuset_t *set); size_t cpuset_size(const cpuset_t *set); DESCRIPTION
This section describes the functions used to create, set, use and destroy the dynamic CPU sets. This API can be used with the POSIX threads, see pthread(3) and affinity(3). The ID of the primary CPU in the system is 0. FUNCTIONS
cpuset_create() Allocates and initializes a clean CPU-set. Returns the pointer to the CPU-set, or NULL on failure. cpuset_destroy(set) Destroy the CPU-set specified by set. cpuset_zero(set) Makes the CPU-set specified by set clean, that is, memory is initialized to zero bytes, and none of the CPUs set. cpuset_set(cpu, set) Sets the CPU specified by cpu in set. Returns zero on success, and -1 if cpu is invalid. cpuset_clr(cpu, set) Clears the CPU specified by cpu in the CPU-set set. Returns zero on success, and -1 if cpu is invalid. cpuset_isset(cpu, set) Checks if CPU specified by cpu is set in the CPU-set set. Returns the positive number if set, zero if not set, and -1 if cpu is invalid. cpuset_size(set) Returns the size in bytes of CPU-set specified by set. SEE ALSO
affinity(3), pset(3), sched(3), schedctl(8), kcpuset(9) HISTORY
The dynamic CPU sets appeared in NetBSD 5.0. BSD
November 2, 2011 BSD
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