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__ppc_get_timebase(3) — Linux manual page

__ppc_get_timebase(3)    Library Functions Manual__ppc_get_timebase(3)

NAME        top

       __ppc_get_timebase, __ppc_get_timebase_freq - get the current       value of the Time Base Register on Power architecture and its       frequency.

LIBRARY        top

       Standard C library (libc,-lc)

SYNOPSIS        top

#include <sys/platform/ppc.h>uint64_t __ppc_get_timebase(void);uint64_t __ppc_get_timebase_freq(void);

DESCRIPTION        top

__ppc_get_timebase() reads the current value of the Time Base       Register and returns its value, while__ppc_get_timebase_freq()       returns the frequency in which the Time Base Register is updated.       The Time Base Register is a 64-bit register provided by Power       Architecture processors.  It stores a monotonically incremented       value that is updated at a system-dependent frequency that may be       different from the processor frequency.

RETURN VALUE        top

__ppc_get_timebase() returns a 64-bit unsigned integer that       represents the current value of the Time Base Register.__ppc_get_timebase_freq() returns a 64-bit unsigned integer that       represents the frequency at which the Time Base Register is       updated.

STANDARDS        top

       GNU.

HISTORY        top

__ppc_get_timebase()              glibc 2.16.__ppc_get_timebase_freq()              glibc 2.17.

EXAMPLES        top

       The following program will calculate the time, in microseconds,       spent between two calls to__ppc_get_timebase().Program source       #include <inttypes.h>       #include <stdint.h>       #include <stdio.h>       #include <stdlib.h>       #include <sys/platform/ppc.h>       /* Maximum value of the Time Base Register: 2^60 - 1.          Source: POWER ISA.  */       #define MAX_TB 0xFFFFFFFFFFFFFFF       int       main(void)       {           uint64_t tb1, tb2, diff;           uint64_t freq;           freq = __ppc_get_timebase_freq();           printf("Time Base frequency = %"PRIu64" Hz\n", freq);           tb1 = __ppc_get_timebase();           // Do some stuff...           tb2 = __ppc_get_timebase();           if (tb2 > tb1) {               diff = tb2 - tb1;           } else {               /* Treat Time Base Register overflow.  */               diff = (MAX_TB - tb2) + tb1;           }           printf("Elapsed time  = %1.2f usecs\n",                  (double) diff * 1000000 / freq);           exit(EXIT_SUCCESS);       }

SEE ALSO        top

time(2),usleep(3)

COLOPHON        top

       This page is part of theman-pages (Linux kernel and C library       user-space interface documentation) project.  Information about       the project can be found at        ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report       for this manual page, see       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.       This page was obtained from the tarball man-pages-6.15.tar.gz       fetched from       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on       2025-08-11.  If you discover any rendering problems in this HTML       version of the page, or you believe there is a better or more up-       to-date source for the page, or you have corrections or       improvements to the information in this COLOPHON (which isnot       part of the original manual page), send a mail to       man-pages@man7.orgLinux man-pages 6.15            2025-05-17__ppc_get_timebase(3)

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