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2011-05-18 Joel Sherrill <joel.sherrill@oarcorp.com>

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* user/conf.t: Add SMP Configuration parameters.
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Joel Sherrill
2011-05-18 23:29:12 +00:00
parent a331ef7325
commit 49115133ad
2 changed files with 47 additions and 5 deletions
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doc/ChangeLog
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@@ -1,3 +1,7 @@
2011-05-18 Joel Sherrill <joel.sherrill@oarcorp.com>
* user/conf.t: Add SMP Configuration parameters.
2011-05-18 Joel Sherrill <joel.sherrill@oarcorp.com>
* user/conf.t: Slight rework to deemphasize not using confdefs.h

48
doc/user/conf.t
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@@ -402,11 +402,12 @@ a scheduling algorithm for an application. For the schedulers built into RTEMS,
@findex CONFIGURE_SCHEDULER_PRIORITY
@item Deterministic Priority Scheduler - This is the default scheduler
in RTEMS and is designed for predictable performance under the highest
loads. It can block or unblock a thread in a constant amount of time.
This scheduler requires a variable amount of memory based upon the number
of priorities configured in the system. This scheduler may be explicitly
selected by defining @code{CONFIGURE_SCHEDULER_PRIORITY}.
in RTEMS for single core applications and is designed for predictable
performance under the highest loads. It can block or unblock a thread
in a constant amount of time. This scheduler requires a variable
amount of memory based upon the number of priorities configured in
the system. This scheduler may be explicitly selected by defining
@code{CONFIGURE_SCHEDULER_PRIORITY}.
@findex CONFIGURE_SCHEDULER_SIMPLE
@item Simple Priority Scheduler - This is an alternative scheduler
@@ -418,6 +419,23 @@ constant time operation with this scheduler. This scheduler is appropriate
for use in small systems where RAM is limited. This scheduler may be explicitly
selected by defining @code{CONFIGURE_SCHEDULER_SIMPLE}.
@findex CONFIGURE_SCHEDULER_SIMPLE_SMP
@item Simple SMP Priority Scheduler - This scheduler is derived from the
Simple Priority Scheduler but is capable of scheduling threads across
multiple cores. It is designed to provide the same task scheduling
behaviour as the Deterministic Priority Scheduler while distributing
threads across multiple cores. Being based upon the Simple Priority
Scheduler, it is also maintains a single sorted list of all ready threads.
Thus blocking or unblocking a thread is not a constant time operation
with this scheduler. In addition, when allocating threads to cores,
the algorithm is not constant time. This algorithm was not designed
with efficiency as a primary design goal. Its primary design goal was to
provide an SMP-aware scheduling algorithm that is simple to understand.
This scheduler is currently the default in SMP configurations and is
only selected when @code{CONFIGURE_SMP_APPLICATION} is defined. In a
configuration with SMP enabled at configure time, it may be explicitly
selected by defining @code{CONFIGURE_SCHEDULER_SIMPLE_SMP}.
@end itemize
The pluggable scheduler interface was added after the 4.10 release series
@@ -450,6 +468,26 @@ For guidance on the configuration macros, please examine
@code{cpukit/sapi/include/confdefs.h} for how these are defined for the
Deterministic Priority Scheduler.
@c
@c
@c
@subsection SMP Specific Configuration Parameters
When RTEMS is configured to support SMP target systems, there are other
configuration parameters which apply.
@itemize @bullet
@findex CONFIGURE_SMP_APPLICATION
@item @code{CONFIGURE_SMP_APPLICATION} must be defined if the application
is to make use of multiple CPU cores in an SMP target system.
@item @code{CONFIGURE_SMP_MAXIMUM_PROCESSORS} must be set to the number
of CPU cores in the SMP configuration. If there are more cores available
than configured, the rest will be ignored.
@end itemize
@c
@c
@c