217 lines
4.6 KiB
HTML
217 lines
4.6 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML><HEAD><TITLE>Man page of __PPC_SET_PPR_MED</TITLE>
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</HEAD><BODY>
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<H1>__PPC_SET_PPR_MED</H1>
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Section: LinuxProgrammer's Manual (3)<BR>Updated: 2017-09-15<BR><A HREF="#index">Index</A>
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<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
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<A NAME="lbAB"> </A>
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<H2>NAME</H2>
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__ppc_set_ppr_med, __ppc_set_ppr_very_low, __ppc_set_ppr_low, __ppc_set_ppr_med_low, __ppc_set_ppr_med_high -
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Set the Program Priority Register
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<B>#include <<A HREF="file:///usr/include/sys/platform/ppc.h">sys/platform/ppc.h</A>></B>
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<P>
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<B>void __ppc_set_ppr_med(void);</B>
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<BR>
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<B>void __ppc_set_ppr_very_low(void);</B>
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<BR>
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<B>void __ppc_set_ppr_low(void);</B>
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<BR>
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<B>void __ppc_set_ppr_med_low(void);</B>
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<BR>
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<B>void __ppc_set_ppr_med_high(void);</B>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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These functions provide access to the
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<I>Program Priority Register</I>
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(PPR) on the Power architecture.
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<P>
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The PPR is a 64-bit register that controls the program's priority.
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By adjusting the PPR value the programmer may improve system
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throughput by causing system resources to be used more
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efficiently, especially in contention situations.
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The available unprivileged states are covered by the following functions:
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<DL COMPACT>
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<DT id="1">*<DD>
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<B>__ppc_set_ppr_med</B>()
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sets the Program Priority Register value to
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<I>medium</I>
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(default).
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<DT id="2">*<DD>
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<B>__ppc_set_ppr_very_low</B>()
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sets the Program Priority Register value to
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<I>very low</I>.
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<DT id="3">*<DD>
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<B>__ppc_set_ppr_low</B>()
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sets the Program Priority Register value to
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<I>low</I>.
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<DT id="4">*<DD>
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<B>__ppc_set_ppr_med_low</B>()
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sets the Program Priority Register value to
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<I>medium low</I>.
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</DL>
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<P>
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The privileged state
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<I>medium high</I>
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may also be set during certain time intervals by problem-state (unprivileged)
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programs, with the following function:
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<DL COMPACT>
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<DT id="5">*<DD>
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<B>__ppc_set_ppr_med_high</B>()
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sets the Program Priority to
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<I>medium high</I>.
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</DL>
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<P>
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If the program priority is medium high when the time interval expires or if an
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attempt is made to set the priority to medium high when it is not allowed, the
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priority is set to medium.
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<A NAME="lbAE"> </A>
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<H2>VERSIONS</H2>
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The functions
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<B>__ppc_set_ppr_med</B>(),
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<B>__ppc_set_ppr_low</B>()
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and
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<B>__ppc_set_ppr_med_low</B>()
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are provided by glibc since version 2.18.
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The functions
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<B>__ppc_set_ppr_very_low</B>()
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and
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<B>__ppc_set_ppr_med_high</B>()
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first appeared in glibc in version 2.23.
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<A NAME="lbAF"> </A>
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<H2>ATTRIBUTES</H2>
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For an explanation of the terms used in this section, see
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<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
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<TABLE BORDER>
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<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
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<TR VALIGN=top><TD>
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<B>__ppc_set_ppr_med</B>(),
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<BR>
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<B>__ppc_set_ppr_very_low</B>(),
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<BR>
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<B>__ppc_set_ppr_low</B>(),
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<BR>
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<B>__ppc_set_ppr_med_low</B>(),
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<BR>
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<B>__ppc_set_ppr_med_high</B>()
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</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
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</TABLE>
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<A NAME="lbAG"> </A>
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<H2>CONFORMING TO</H2>
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These functions are nonstandard GNU extensions.
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<A NAME="lbAH"> </A>
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<H2>NOTES</H2>
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The functions
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<B>__ppc_set_ppr_very_low</B>()
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and
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<B>__ppc_set_ppr_med_high</B>()
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will be defined by
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<I><<A HREF="file:///usr/include/sys/platform/ppc.h">sys/platform/ppc.h</A>></I>
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if
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<B>_ARCH_PWR8</B>
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is defined.
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Availability of these functions can be tested using
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<B>#ifdef _ARCH_PWR8</B>.
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<A NAME="lbAI"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?3+__ppc_yield">__ppc_yield</A></B>(3)
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<P>
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<I>Power ISA, Book II - Section 3.1 (Program Priority Registers)</I>
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<A NAME="lbAJ"> </A>
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<H2>COLOPHON</H2>
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This page is part of release 5.05 of the Linux
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<I>man-pages</I>
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project.
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A description of the project,
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information about reporting bugs,
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and the latest version of this page,
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can be found at
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<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
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<P>
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<HR>
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<A NAME="index"> </A><H2>Index</H2>
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<DL>
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<DT id="6"><A HREF="#lbAB">NAME</A><DD>
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<DT id="7"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="8"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="9"><A HREF="#lbAE">VERSIONS</A><DD>
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<DT id="10"><A HREF="#lbAF">ATTRIBUTES</A><DD>
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<DT id="11"><A HREF="#lbAG">CONFORMING TO</A><DD>
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<DT id="12"><A HREF="#lbAH">NOTES</A><DD>
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<DT id="13"><A HREF="#lbAI">SEE ALSO</A><DD>
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<DT id="14"><A HREF="#lbAJ">COLOPHON</A><DD>
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</DL>
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<HR>
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This document was created by
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<A HREF="/cgi-bin/man/man2html">man2html</A>,
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using the manual pages.<BR>
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Time: 00:05:52 GMT, March 31, 2021
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