+++ /dev/null
-<!-- Copyright (C) 2003 Red Hat, Inc. -->
-<!-- This material may be distributed only subject to the terms -->
-<!-- and conditions set forth in the Open Publication License, v1.0 -->
-<!-- or later (the latest version is presently available at -->
-<!-- http://www.opencontent.org/openpub/). -->
-<!-- Distribution of the work or derivative of the work in any -->
-<!-- standard (paper) book form is prohibited unless prior -->
-<!-- permission is obtained from the copyright holder. -->
-<HTML
-><HEAD
-><TITLE
->Thread priorities</TITLE
-><meta name="MSSmartTagsPreventParsing" content="TRUE">
-<META
-NAME="GENERATOR"
-CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+
-"><LINK
-REL="HOME"
-TITLE="eCos Reference Manual"
-HREF="ecos-ref.html"><LINK
-REL="UP"
-TITLE="The eCos Kernel"
-HREF="kernel.html"><LINK
-REL="PREVIOUS"
-TITLE="Thread termination"
-HREF="kernel-thread-termination.html"><LINK
-REL="NEXT"
-TITLE="Per-thread data"
-HREF="kernel-thread-data.html"></HEAD
-><BODY
-CLASS="REFENTRY"
-BGCOLOR="#FFFFFF"
-TEXT="#000000"
-LINK="#0000FF"
-VLINK="#840084"
-ALINK="#0000FF"
-><DIV
-CLASS="NAVHEADER"
-><TABLE
-SUMMARY="Header navigation table"
-WIDTH="100%"
-BORDER="0"
-CELLPADDING="0"
-CELLSPACING="0"
-><TR
-><TH
-COLSPAN="3"
-ALIGN="center"
->eCos Reference Manual</TH
-></TR
-><TR
-><TD
-WIDTH="10%"
-ALIGN="left"
-VALIGN="bottom"
-><A
-HREF="kernel-thread-termination.html"
-ACCESSKEY="P"
->Prev</A
-></TD
-><TD
-WIDTH="80%"
-ALIGN="center"
-VALIGN="bottom"
-></TD
-><TD
-WIDTH="10%"
-ALIGN="right"
-VALIGN="bottom"
-><A
-HREF="kernel-thread-data.html"
-ACCESSKEY="N"
->Next</A
-></TD
-></TR
-></TABLE
-><HR
-ALIGN="LEFT"
-WIDTH="100%"></DIV
-><H1
-><A
-NAME="KERNEL-THREAD-PRIORITIES">Thread priorities</H1
-><DIV
-CLASS="REFNAMEDIV"
-><A
-NAME="AEN616"
-></A
-><H2
->Name</H2
->cyg_thread_get_priority, cyg_thread_get_current_priority, cyg_thread_set_priority -- Examine and manipulate thread priorities</DIV
-><DIV
-CLASS="REFSYNOPSISDIV"
-><A
-NAME="AEN621"><H2
->Synopsis</H2
-><DIV
-CLASS="FUNCSYNOPSIS"
-><A
-NAME="AEN622"><P
-></P
-><TABLE
-BORDER="5"
-BGCOLOR="#E0E0F0"
-WIDTH="70%"
-><TR
-><TD
-><PRE
-CLASS="FUNCSYNOPSISINFO"
->#include <cyg/kernel/kapi.h>
- </PRE
-></TD
-></TR
-></TABLE
-><P
-><CODE
-><CODE
-CLASS="FUNCDEF"
->cyg_priority_t cyg_thread_get_priority</CODE
->(cyg_handle_t thread);</CODE
-></P
-><P
-><CODE
-><CODE
-CLASS="FUNCDEF"
->cyg_priority_t cyg_thread_get_current_priority</CODE
->(cyg_handle_t thread);</CODE
-></P
-><P
-><CODE
-><CODE
-CLASS="FUNCDEF"
->void cyg_thread_set_priority</CODE
->(cyg_handle_t thread, cyg_priority_t priority);</CODE
-></P
-><P
-></P
-></DIV
-></DIV
-><DIV
-CLASS="REFSECT1"
-><A
-NAME="AEN641"
-></A
-><H2
->Description</H2
-><P
->Typical schedulers use the concept of a thread priority to determine
-which thread should run next. Exactly what this priority consists of
-will depend on the scheduler, but a typical implementation would be a
-small integer in the range 0 to 31, with 0 being the highest priority.
-Usually only the idle thread will run at the lowest priority. The
-exact number of priority levels available depends on the
-configuration, typically the option
-<TT
-CLASS="VARNAME"
->CYGNUM_KERNEL_SCHED_PRIORITIES</TT
->.
- </P
-><P
-><TT
-CLASS="FUNCTION"
->cyg_thread_get_priority</TT
-> can be used to determine
-the priority of a thread, or more correctly the value last used in a
-<TT
-CLASS="FUNCTION"
->cyg_thread_set_priority</TT
-> call or when the thread
-was first created. In some circumstances it is possible that the
-thread is actually running at a higher priority. For example, if it
-owns a mutex and priority ceilings or inheritance is being used to
-prevent priority inversion problems, then the thread's priority may
-have been boosted temporarily.
-<TT
-CLASS="FUNCTION"
->cyg_thread_get_current_priority</TT
-> returns the real
-current priority.
- </P
-><P
->In many applications appropriate thread priorities can be determined
-and allocated statically. However, if it is necessary for a thread's
-priority to change at run-time then the
-<TT
-CLASS="FUNCTION"
->cyg_thread_set_priority</TT
-> function provides this
-functionality.
- </P
-></DIV
-><DIV
-CLASS="REFSECT1"
-><A
-NAME="KERNEL-THREAD-PRIORITIES-CONTEXT"
-></A
-><H2
->Valid contexts</H2
-><P
-><TT
-CLASS="FUNCTION"
->cyg_thread_get_priority</TT
-> and
-<TT
-CLASS="FUNCTION"
->cyg_thread_get_current_priority</TT
-> can be called
-from thread or DSR context, although the latter is rarely useful.
-<TT
-CLASS="FUNCTION"
->cyg_thread_set_priority</TT
-> should also only be
-called from thread context.
- </P
-></DIV
-><DIV
-CLASS="NAVFOOTER"
-><HR
-ALIGN="LEFT"
-WIDTH="100%"><TABLE
-SUMMARY="Footer navigation table"
-WIDTH="100%"
-BORDER="0"
-CELLPADDING="0"
-CELLSPACING="0"
-><TR
-><TD
-WIDTH="33%"
-ALIGN="left"
-VALIGN="top"
-><A
-HREF="kernel-thread-termination.html"
-ACCESSKEY="P"
->Prev</A
-></TD
-><TD
-WIDTH="34%"
-ALIGN="center"
-VALIGN="top"
-><A
-HREF="ecos-ref.html"
-ACCESSKEY="H"
->Home</A
-></TD
-><TD
-WIDTH="33%"
-ALIGN="right"
-VALIGN="top"
-><A
-HREF="kernel-thread-data.html"
-ACCESSKEY="N"
->Next</A
-></TD
-></TR
-><TR
-><TD
-WIDTH="33%"
-ALIGN="left"
-VALIGN="top"
->Thread termination</TD
-><TD
-WIDTH="34%"
-ALIGN="center"
-VALIGN="top"
-><A
-HREF="kernel.html"
-ACCESSKEY="U"
->Up</A
-></TD
-><TD
-WIDTH="33%"
-ALIGN="right"
-VALIGN="top"
->Per-thread data</TD
-></TR
-></TABLE
-></DIV
-></BODY
-></HTML
->
\ No newline at end of file
projects / karo-tx-redboot.git / blobdiff