Changeset 4911513 in rtems


Ignore:
Timestamp:
May 18, 2011, 11:29:12 PM (9 years ago)
Author:
Joel Sherrill <joel.sherrill@…>
Branches:
4.11, master
Children:
20e3bf7
Parents:
a331ef73
Message:

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

  • user/conf.t: Add SMP Configuration parameters.
Location:
doc
Files:
2 edited

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  • doc/ChangeLog

    ra331ef73 r4911513  
     12011-05-18      Joel Sherrill <joel.sherrill@oarcorp.com>
     2
     3        * user/conf.t: Add SMP Configuration parameters.
     4
    152011-05-18      Joel Sherrill <joel.sherrill@oarcorp.com>
    26
  • doc/user/conf.t

    ra331ef73 r4911513  
    403403@findex CONFIGURE_SCHEDULER_PRIORITY
    404404@item Deterministic Priority Scheduler - This is the default scheduler
    405 in RTEMS and is designed for predictable performance under the highest
    406 loads.  It can block or unblock a thread in a constant amount of time.
    407 This scheduler requires a variable amount of memory based upon the number
    408 of priorities configured in the system.  This scheduler may be explicitly
    409 selected by defining @code{CONFIGURE_SCHEDULER_PRIORITY}.
     405in RTEMS for single core applications and is designed for predictable
     406performance under the highest loads.  It can block or unblock a thread
     407in a constant amount of time.  This scheduler requires a variable
     408amount of memory based upon the number of priorities configured in
     409the system.  This scheduler may be explicitly selected by defining
     410@code{CONFIGURE_SCHEDULER_PRIORITY}.
    410411
    411412@findex CONFIGURE_SCHEDULER_SIMPLE
     
    419420selected by defining @code{CONFIGURE_SCHEDULER_SIMPLE}.
    420421
     422@findex CONFIGURE_SCHEDULER_SIMPLE_SMP
     423@item Simple SMP Priority Scheduler - This scheduler is derived from the
     424Simple Priority Scheduler but is capable of scheduling threads across
     425multiple cores.  It is designed to provide the same task scheduling
     426behaviour as the Deterministic Priority Scheduler while distributing
     427threads across multiple cores.  Being based upon the Simple Priority
     428Scheduler, it is also maintains a single sorted list of all ready threads.
     429Thus blocking or unblocking a thread is not a constant time operation
     430with this scheduler.  In addition, when allocating threads to cores,
     431the algorithm is not constant time.  This algorithm was not designed
     432with efficiency as a primary design goal.  Its primary design goal was to
     433provide an SMP-aware scheduling algorithm that is simple to understand.
     434This scheduler is currently the default in SMP configurations and is
     435only selected when @code{CONFIGURE_SMP_APPLICATION} is defined.  In a
     436configuration with SMP enabled at configure time, it may be explicitly
     437selected by defining @code{CONFIGURE_SCHEDULER_SIMPLE_SMP}.
     438
    421439@end itemize
    422440
     
    450468@code{cpukit/sapi/include/confdefs.h} for how these are defined for the
    451469Deterministic Priority Scheduler.
     470
     471@c
     472@c
     473@c
     474@subsection SMP Specific Configuration Parameters
     475
     476When RTEMS is configured to support SMP target systems, there are other
     477configuration parameters which apply.
     478
     479@itemize @bullet
     480
     481@findex CONFIGURE_SMP_APPLICATION
     482@item @code{CONFIGURE_SMP_APPLICATION} must be defined if the application
     483is to make use of multiple CPU cores in an SMP target system.
     484
     485@item @code{CONFIGURE_SMP_MAXIMUM_PROCESSORS} must be set to the number
     486of CPU cores in the SMP configuration.  If there are more cores available
     487than configured, the rest will be ignored.
     488
     489@end itemize
    452490
    453491@c
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