Section (3) __ppc_set_ppr_med
__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
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_zsingle_quotesz_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
__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
__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.
__ppc_set_ppr_med_low() are provided by
glibc since version 2.18. The functions
__ppc_set_ppr_med_high() first appeared in
glibc in version 2.23.
For an explanation of the terms used in this section, see attributes(7).
__ppc_set_ppr_med_high() will be defined by
_ARCH_PWR8 is defined. Availability of
these functions can be tested using #ifdef _ARCH_PWR8.
Power ISA, Book II - Section 3.1 (Program Priority Registers)
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