__ppc_set_ppr_med(3) Library Functions Manual __ppc_set_ppr_med(3)
Programmer's Manual"
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 Prior-
ity Register
LIBRARY
Standard C library (libc, -lc)
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 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 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 since glibc 2.18. The functions
__ppc_set_ppr_very_low() and __ppc_set_ppr_med_high() first appeared in
glibc 2.23.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(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() │ │ │
└────────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
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)
Linux man-pages 6.03 2022-12-15 __ppc_set_ppr_med(3)
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