schedule_type¶
The ways loop iterations can be divided among threads.
Declaration¶
Syntax¶
schedule_type
= Static | Dynamic | Guided | Auto | Runtime
Values¶
Value |
Meaning |
|---|---|
|
divide the iterations into chunks up front and assign them in order. |
|
hand out a chunk whenever a thread becomes free. |
|
like |
|
let the implementation choose. |
|
take the schedule from the environment at run time. |
Return values¶
None.
Description¶
Static costs nothing at run time and is right when the iterations take
similar time. The others pay for scheduling in exchange for balancing uneven
work.
Examples¶
An ASR text document that uses it:
(TranslationUnit
:symtab (SymbolTable
:id 0
:symbols {
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)
:intboz_type :Decimal
)
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:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
]
:physical_type :FixedSizeArray
)
:type_declaration nil
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)
"i" (Variable
:parent_symtab 1
:name "i"
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:intent :Local
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:type (Integer
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)
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)
"n" (Variable
:parent_symtab 1
:name "n"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Integer
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
"run" (Variable
:parent_symtab 1
:name "run"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Logical
:kind 4
)
:type_declaration nil
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:contiguous_attr false
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:pass_attr :NotMethod
:self_argument nil
:codims []
)
"total" (Variable
:parent_symtab 1
:name "total"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Integer
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
}
)
:name "main"
:dependencies []
:body [
(OMPRegion
:region :Parallel
:clauses [
(OMPPrivate
:vars [
(Var
:v (SymbolRef 1 "i")
)
]
)
(OMPShared
:vars [
(Var
:v (SymbolRef 1 "a")
)
]
)
(OMPFirstPrivate
:vars [
(Var
:v (SymbolRef 1 "n")
)
]
)
(OMPNumThreads
:num_threads (IntegerConstant
:n 4
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
(OMPIf
:condition (Var
:v (SymbolRef 1 "run")
)
)
]
:body [
(OMPRegion
:region :Do
:clauses [
(OMPSchedule
:kind :Static
:chunk_size (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
(OMPCollapse
:count (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
(OMPReduction
:operator :ReduceAdd
:vars [
(Var
:v (SymbolRef 1 "total")
)
]
)
(OMPLastPrivate
:vars [
(Var
:v (SymbolRef 1 "i")
)
]
)
(OMPNowait)
]
:body [
(DoLoop
:name nil
:head (do_loop_head
:v (Var
:v (SymbolRef 1 "i")
)
:start (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
:end (IntegerConstant
:n 3
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
:increment (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
:body [
(Assignment
:target (Var
:v (SymbolRef 1 "total")
)
:value (IntegerBinOp
:left (Var
:v (SymbolRef 1 "total")
)
:op :Add
:right (Var
:v (SymbolRef 1 "i")
)
:type (Integer
:kind 4
)
:value nil
)
:overloaded nil
:realloc_lhs false
:move_allocation false
)
]
:orelse []
)
]
)
]
)
(OMPRegion
:region :Target
:clauses [
(OMPMap
:type :ToFrom
:vars [
(Var
:v (SymbolRef 1 "a")
)
]
)
(OMPDevice
:device (IntegerConstant
:n 0
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
]
:body [
(OMPRegion
:region :Teams
:clauses [
(OMPNumTeams
:num_teams (IntegerConstant
:n 2
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
(OMPThreadLimit
:thread_limit (IntegerConstant
:n 64
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
]
:body [
(Assignment
:target (Var
:v (SymbolRef 1 "total")
)
:value (IntegerConstant
:n 0
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
:overloaded nil
:realloc_lhs false
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)
]
)
]
)
]
)
}
)
:items []
)