__ppc_set_ppr_med(3) — Linux manual page


__PPC_SET_PPR_MED(3)    LinuxProgrammer's Manual    __PPC_SET_PPR_MED(3)

NAME         top

       __ppc_set_ppr_med, __ppc_set_ppr_very_low, __ppc_set_ppr_low,
       __ppc_set_ppr_med_low, __ppc_set_ppr_med_high - Set the Program
       Priority Register

SYNOPSIS         top

       #include <sys/platform/ppc.h>

       void __ppc_set_ppr_med(void);
       void __ppc_set_ppr_very_low(void);
       void __ppc_set_ppr_low(void);
       void __ppc_set_ppr_med_low(void);
       void __ppc_set_ppr_med_high(void);

DESCRIPTION         top

       These functions provide access to the Program Priority Register
       (PPR) on the Power architecture.

       The PPR is a 64-bit register that controls the program's
       priority.  By adjusting the PPR value the programmer may improve
       system throughput by causing system resources to be used more
       efficiently, especially in contention situations.  The available
       unprivileged states are covered by the following functions:

       *  __ppc_set_ppr_med() sets the Program Priority Register value
          to medium (default).

       *  __ppc_set_ppr_very_low() sets the Program Priority Register
          value to very low.

       *  __ppc_set_ppr_low() sets the Program Priority Register value
          to low.

       *  __ppc_set_ppr_med_low() sets the Program Priority Register
          value to medium low.

       The privileged state medium high may also be set during certain
       time intervals by problem-state (unprivileged) programs, with the
       following function:

       *  __ppc_set_ppr_med_high() sets the Program Priority to medium

       If the program priority is medium high when the time interval
       expires or if an attempt is made to set the priority to medium
       high when it is not allowed, the priority is set to medium.

VERSIONS         top

       The functions __ppc_set_ppr_med(), __ppc_set_ppr_low(), and
       __ppc_set_ppr_med_low() are provided by glibc since version 2.18.
       The functions __ppc_set_ppr_very_low() and
       __ppc_set_ppr_med_high() first appeared in glibc in version 2.23.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see

       │Interface                             Attribute     Value   │
       │__ppc_set_ppr_med(),                  │ Thread safety │ MT-Safe │
       │__ppc_set_ppr_very_low(),             │               │         │
       │__ppc_set_ppr_low(),                  │               │         │
       │__ppc_set_ppr_med_low(),              │               │         │
       │__ppc_set_ppr_med_high()              │               │         │

CONFORMING TO         top

       These functions are nonstandard GNU extensions.

NOTES         top

       The functions __ppc_set_ppr_very_low() and
       __ppc_set_ppr_med_high() will be defined by <sys/platform/ppc.h>
       if _ARCH_PWR8 is defined.  Availability of these functions can be
       tested using #ifdef _ARCH_PWR8.

SEE ALSO         top


       Power ISA, Book II - Section 3.1 (Program Priority Registers)

COLOPHON         top

       This page is part of release 5.13 of the Linux man-pages project.
       A description of the project, information about reporting bugs,
       and the latest version of this page, can be found at

GNU C Library                  2021-03-22           __PPC_SET_PPR_MED(3)

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