mirror of https://github.com/mkerrisk/man-pages
131 lines
3.8 KiB
Groff
131 lines
3.8 KiB
Groff
.\" Copyright (c) 2015, 2016 IBM Corporation.
|
|
.\"
|
|
.\" %%%LICENSE_START(VERBATIM)
|
|
.\" Permission is granted to make and distribute verbatim copies of this
|
|
.\" manual provided the copyright notice and this permission notice are
|
|
.\" preserved on all copies.
|
|
.\"
|
|
.\" Permission is granted to copy and distribute modified versions of
|
|
.\" this manual under the conditions for verbatim copying, provided that
|
|
.\" the entire resulting derived work is distributed under the terms of
|
|
.\" a permission notice identical to this one.
|
|
.\"
|
|
.\" Since the Linux kernel and libraries are constantly changing, this
|
|
.\" manual page may be incorrect or out-of-date. The author(s) assume.
|
|
.\" no responsibility for errors or omissions, or for damages resulting.
|
|
.\" from the use of the information contained herein. The author(s) may.
|
|
.\" not have taken the same level of care in the production of this.
|
|
.\" manual, which is licensed free of charge, as they might when working.
|
|
.\" professionally.
|
|
.\"
|
|
.\" Formatted or processed versions of this manual, if unaccompanied by
|
|
.\" the source, must acknowledge the copyright and authors of this work.
|
|
.\" %%%LICENSE_END
|
|
.\"
|
|
.TH __PPC_SET_PPR_MED 3 2020-12-21 "GNU C Library" "Linux\
|
|
Programmer's Manual"
|
|
.SH 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
|
|
.SH SYNOPSIS
|
|
.nf
|
|
.B #include <sys/platform/ppc.h>
|
|
.PP
|
|
.B void __ppc_set_ppr_med(void);
|
|
.B void __ppc_set_ppr_very_low(void);
|
|
.B void __ppc_set_ppr_low(void);
|
|
.B void __ppc_set_ppr_med_low(void);
|
|
.B void __ppc_set_ppr_med_high(void);
|
|
.fi
|
|
.SH DESCRIPTION
|
|
These functions provide access to the
|
|
.I Program Priority Register
|
|
(PPR) on the Power architecture.
|
|
.PP
|
|
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:
|
|
.IP * 3
|
|
.BR __ppc_set_ppr_med ()
|
|
sets the Program Priority Register value to
|
|
.IR medium
|
|
(default).
|
|
.IP *
|
|
.BR __ppc_set_ppr_very_low ()
|
|
sets the Program Priority Register value to
|
|
.IR "very low" .
|
|
.IP *
|
|
.BR __ppc_set_ppr_low ()
|
|
sets the Program Priority Register value to
|
|
.IR low .
|
|
.IP *
|
|
.BR __ppc_set_ppr_med_low ()
|
|
sets the Program Priority Register value to
|
|
.IR "medium low" .
|
|
.PP
|
|
The privileged state
|
|
.IR "medium high"
|
|
may also be set during certain time intervals by problem-state (unprivileged)
|
|
programs, with the following function:
|
|
.IP * 3
|
|
.BR __ppc_set_ppr_med_high ()
|
|
sets the Program Priority to
|
|
.IR "medium high" .
|
|
.PP
|
|
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.
|
|
.SH VERSIONS
|
|
The functions
|
|
.BR __ppc_set_ppr_med (),
|
|
.BR __ppc_set_ppr_low (),
|
|
and
|
|
.BR __ppc_set_ppr_med_low ()
|
|
are provided by glibc since version 2.18.
|
|
The functions
|
|
.BR __ppc_set_ppr_very_low ()
|
|
and
|
|
.BR __ppc_set_ppr_med_high ()
|
|
first appeared in glibc in version 2.23.
|
|
.SH ATTRIBUTES
|
|
For an explanation of the terms used in this section, see
|
|
.BR attributes (7).
|
|
.ad l
|
|
.nh
|
|
.TS
|
|
allbox;
|
|
lbx lb lb
|
|
l l l.
|
|
Interface Attribute Value
|
|
T{
|
|
.BR __ppc_set_ppr_med (),
|
|
.BR __ppc_set_ppr_very_low (),
|
|
.BR __ppc_set_ppr_low (),
|
|
.BR __ppc_set_ppr_med_low (),
|
|
.BR __ppc_set_ppr_med_high ()
|
|
T} Thread safety MT-Safe
|
|
.TE
|
|
.hy
|
|
.ad
|
|
.sp 1
|
|
.SH CONFORMING TO
|
|
These functions are nonstandard GNU extensions.
|
|
.SH NOTES
|
|
The functions
|
|
.BR __ppc_set_ppr_very_low ()
|
|
and
|
|
.BR __ppc_set_ppr_med_high ()
|
|
will be defined by
|
|
.I <sys/platform/ppc.h>
|
|
if
|
|
.B _ARCH_PWR8
|
|
is defined.
|
|
Availability of these functions can be tested using
|
|
.BR "#ifdef _ARCH_PWR8" .
|
|
.SH SEE ALSO
|
|
.BR __ppc_yield (3)
|
|
.PP
|
|
.IR "Power ISA, Book\ II - Section\ 3.1 (Program Priority Registers)"
|