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

NAME

       __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 Reg-
       ister

SYNOPSIS

       #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

       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 cov-
       ered 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 high.

       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

       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

       For an explanation of the terms used in this section, see attributes(7).

       +---------------------------+---------------+---------+
       |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

       These functions are nonstandard GNU extensions.

NOTES

       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

       __ppc_yield(3)

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

GNU C Library							    2017-09-15						      __PPC_SET_PPR_MED(3)