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Diffstat (limited to 'spec/acfg/if/max-priority.yml')
-rw-r--r-- | spec/acfg/if/max-priority.yml | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/spec/acfg/if/max-priority.yml b/spec/acfg/if/max-priority.yml new file mode 100644 index 00000000..8f561f30 --- /dev/null +++ b/spec/acfg/if/max-priority.yml @@ -0,0 +1,58 @@ +SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause +appl-config-option-type: integer +constraints: + set: + - 3 + - 7 + - 31 + - 63 + - 127 + - 255 +copyrights: +- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) +default-value: 255 +description: | + For the following schedulers + + * ${.:/document-reference/scheduler-priority}, which is the default in uniprocessor + configurations and can be configured through the + ${scheduler-priority:/name} configuration option, + + * ${.:/document-reference/scheduler-smp-priority} which can be configured through the + ${scheduler-priority-smp:/name} configuration option, and + + * ${.:/document-reference/scheduler-smp-priority-affinity} which can be configured through the + ${scheduler-priority-affinity-smp:/name} configuration option + + this configuration option specifies the maximum numeric priority of any task + for these schedulers and one less that the number of priority levels for + these schedulers. For all other schedulers provided by RTEMS, this + configuration option has no effect. +enabled-by: true +index-entries: +- maximum priority +- number of priority levels +interface-type: appl-config-option +links: +- role: appl-config-group-member + uid: group-schedgeneral +name: CONFIGURE_MAXIMUM_PRIORITY +notes: | + The numerically greatest priority is the logically lowest priority in the + system and will thus be used by the IDLE task. + + Priority zero is reserved for internal use by RTEMS and is not available to + applications. + + Reducing the number of priorities through this configuration option reduces + the amount of memory allocated by the schedulers listed above. These + schedulers use a chain control structure per priority and this structure + consists of three pointers. On a 32-bit architecture, the allocated memory + is 12 bytes * (``CONFIGURE_MAXIMUM_PRIORITY`` + 1), e.g. 3072 bytes for 256 + priority levels (default), 48 bytes for 4 priority levels + (``CONFIGURE_MAXIMUM_PRIORITY == 3``). + + The default value is 255, because RTEMS shall support 256 priority levels to + be compliant with various standards. These priorities range from 0 to 255. +text: '' +type: interface |