mirror of
https://gitlab.rtems.org/rtems/rtos/rtems.git
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2006-09-14 Joel Sherrill <joel@OARcorp.com>
* new_chapters/Makefile.am, new_chapters/gen_section, new_chapters/new_chapters.texi, user/Makefile.am, user/c_user.texi, user/dirstat.texi: Promote CPU Usage to first class citizen. Rename to start with rtems_ and include documentation in user guide. * user/cpuuse.t: New file. * new_chapters/cpuuse.t: Removed.
This commit is contained in:
Joel Sherrill
@@ -18,7 +18,7 @@ GENERATED_FILES = overview.texi concepts.texi datatypes.texi init.texi \
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task.texi intr.texi clock.texi timer.texi sem.texi msg.texi event.texi \
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signal.texi part.texi region.texi dpmem.texi io.texi fatal.texi \
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schedule.texi rtmon.texi bsp.texi userext.texi conf.texi mp.texi \
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stackchk.texi
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stackchk.texi cpuuse.texi
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COMMON_FILES += $(top_srcdir)/common/cpright.texi
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@@ -161,12 +161,17 @@ mp.texi: mp.t
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stackchk.texi: stackchk.t
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$(BMENU2) -p "Multiprocessing Manager MULTIPROCESSING_ANNOUNCE - Announce the arrival of a packet" \
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-u "Top" \
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-n "CPU Usage Statistics" < $< > $@
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cpuuse.texi: cpuuse.t
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$(BMENU2) -p "Stack Bounds Checker stack_checker_dump_usage - Report Task Stack Usage" \
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-u "Top" \
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-n "Directive Status Codes" < $< > $@
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EXTRA_DIST = bsp.t concepts.t clock.t datatypes.t conf.t dpmem.t event.t \
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fatal.t init.t intr.t io.t mp.t msg.t overview.t part.t region.t rtmon.t \
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sem.t schedule.t signal.t stackchk.t task.t timer.t userext.t \
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EXTRA_DIST = bsp.t clock.t concepts.t cpuuse.t datatypes.t conf.t dpmem.t \
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event.t fatal.t init.t intr.t io.t mp.t msg.t overview.t part.t region.t \
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rtmon.t sem.t schedule.t signal.t stackchk.t task.t timer.t userext.t \
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$(TXT_FILES) $(PNG_FILES) $(EPS_IMAGES) $(noinst_DATA)
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CLEANFILES += c_user.info c_user.info-? c_user.info-??
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@@ -101,6 +101,7 @@
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@include conf.texi
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@include mp.texi
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@include stackchk.texi
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@include cpuuse.texi
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@include dirstat.texi
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@include example.texi
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@include glossary.texi
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@@ -136,6 +137,7 @@ This is the online version of the RTEMS C User's Guide.
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* Configuring a System::
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* Multiprocessing Manager::
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* Stack Bounds Checker::
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* CPU Usage Statistics::
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* Directive Status Codes::
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* Example Application::
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* Glossary::
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@@ -0,0 +1,143 @@
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@c
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@c COPYRIGHT (c) 1988-2002.
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@c On-Line Applications Research Corporation (OAR).
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@c All rights reserved.
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@c
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@c $Id$
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@c
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@chapter CPU Usage Statistics
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@section Introduction
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The CPU usage statistics manager is an RTEMS support
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component that provides a convenient way to manipulate
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the CPU usage information associated with each task
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The routines provided by the CPU usage statistics manager are:
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@itemize @bullet
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@item @code{@value{DIRPREFIX}cpu_usage_report} - Report CPU Usage Statistics
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@item @code{@value{DIRPREFIX}cpu_usage_reset} - Reset CPU Usage Statistics
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@end itemize
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@section Background
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@section Operations
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@section Report CPU Usage Statistics
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@subsection Reporting Period Statistics
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The application may dynamically report the CPU usage for every
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task in the system by calling the
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@code{@value{DIRPREFIX}cpu_usage_report} routine.
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This routine prints a table with the following information per task:
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@itemize @bullet
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@item task id
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@item task name
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@item number of clock ticks executed
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@item percentage of time consumed by this task
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@end itemize
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The following is an example of the report generated:
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@example
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@group
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CPU Usage by thread
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ID NAME TICKS PERCENT
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0x04010001 IDLE 0 0.000
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0x08010002 TA1 1203 0.748
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0x08010003 TA2 203 0.126
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0x08010004 TA3 202 0.126
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Ticks since last reset = 1600
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Total Units = 1608
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@end group
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@end example
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Notice that the "Total Units" is greater than the ticks per reset.
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This is an artifact of the way in which RTEMS keeps track of CPU
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usage. When a task is context switched into the CPU, the number
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of clock ticks it has executed is incremented. While the task
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is executing, this number is incremented on each clock tick.
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Otherwise, if a task begins and completes execution between
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successive clock ticks, there would be no way to tell that it
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executed at all.
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Another thing to keep in mind when looking at idle time, is that
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many systems -- especially during debug -- have a task providing
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some type of debug interface. It is usually fine to think of the
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total idle time as being the sum of the IDLE task and a debug
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task that will not be included in a production build of an application.
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@section Reset CPU Usage Statistics
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Invoking the @code{@value{DIRPREFIX}cpu_usage_reset} routine resets
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the CPU usage statistics for all tasks in the system.
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@section Directives
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This section details the CPU usage statistics manager's directives.
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A subsection is dedicated to each of this manager's directives
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and describes the calling sequence, related constants, usage,
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and status codes.
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@page
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@subsection cpu_usage_report - Report CPU Usage Statistics
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@subheading CALLING SEQUENCE:
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@ifset is-C
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@example
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void rtems_cpu_usage_report( void );
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@end example
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@end ifset
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@ifset is-Ada
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@example
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An Ada interface is not currently available.
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@end example
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@end ifset
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@subheading STATUS CODES: NONE
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@subheading DESCRIPTION:
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This routine prints out a table detailing the CPU usage statistics for
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all tasks in the system.
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@subheading NOTES:
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NONE
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@page
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@subsection cpu_usage_reset - Reset CPU Usage Statistics
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@subheading CALLING SEQUENCE:
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@ifset is-C
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@example
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void rtems_cpu_usage_reset( void );
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@end example
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@end ifset
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@ifset is-Ada
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@example
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An Ada interface is not currently available.
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@end example
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@end ifset
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@subheading STATUS CODES: NONE
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@subheading DESCRIPTION:
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This routine re-initializes the CPU usage statistics for all tasks
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in the system to their initial state. The initial state is that
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a task has not executed and thus has consumed no CPU time.
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default state which is when zero period executions have occurred.
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@subheading NOTES:
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NONE
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@@ -7,7 +7,7 @@
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@c
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@ifinfo
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@node Directive Status Codes, Example Application, Stack Bounds Checker stack_checker_dump_usage - Report Task Stack Usage, Top
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@node Directive Status Codes, Example Application, CPU Usage Statistics cpu_usage_reset - Reset CPU Usage Statistics, Top
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@end ifinfo
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@chapter Directive Status Codes
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@table @b
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