__PPC_SET_PPR_MED
Section: LinuxProgrammer's Manual (3)
Updated: 2021-03-22
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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 Register
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 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(),
__ppc_set_ppr_very_low(),
__ppc_set_ppr_low(),
__ppc_set_ppr_med_low(),
__ppc_set_ppr_med_high()
| Thread safety | MT-Safe
|
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)
COLOPHON
This page is part of release 5.11 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
https://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- VERSIONS
-
- ATTRIBUTES
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-
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Time: 06:22:44 GMT, May 09, 2021