XcalableMP Programming Model and Language
3
it is assumed that accessing remote memory may be much slower than accessing
local memory.
1.2 Execution Model
The execution entities in an XMP program are referred to as XMP nodes or, more
simply, nodes, which has its own memory and can communicate with each other.
An XcalableMP program execution is based on the Single Program Multiple
Data (SPMD) model, where each node starts execution from the same main routine,
and continues to execute the same code independently (i.e. asynchronously) until it
encounters an XcalableMP construct (Fig. 2).
A set of nodes that executes a procedure, statement, loop, a block, etc. is referred
to as its executing node set, and is determined by the innermost task, loop, or
array directive surrounding it dynamically, or at runtime. The current executing
node set is an executing node set of the current context, which is managed by the
XcalableMP runtime system on each node.
The current executing node set at the beginning of the program execution, or
entire node set, is a node set that contains all the available nodes, which can be
specified in an implementation-defined way (e.g. through a command-line option).
When a node encounters at runtime either a loop, array, or task construct,
and is contained by the node set specified (explicitly or implicitly) by the on clause
Fig. 2 Execution model of
XMP
3
it is assumed that accessing remote memory may be much slower than accessing
local memory.
1.2 Execution Model
The execution entities in an XMP program are referred to as XMP nodes or, more
simply, nodes, which has its own memory and can communicate with each other.
An XcalableMP program execution is based on the Single Program Multiple
Data (SPMD) model, where each node starts execution from the same main routine,
and continues to execute the same code independently (i.e. asynchronously) until it
encounters an XcalableMP construct (Fig. 2).
A set of nodes that executes a procedure, statement, loop, a block, etc. is referred
to as its executing node set, and is determined by the innermost task, loop, or
array directive surrounding it dynamically, or at runtime. The current executing
node set is an executing node set of the current context, which is managed by the
XcalableMP runtime system on each node.
The current executing node set at the beginning of the program execution, or
entire node set, is a node set that contains all the available nodes, which can be
specified in an implementation-defined way (e.g. through a command-line option).
When a node encounters at runtime either a loop, array, or task construct,
and is contained by the node set specified (explicitly or implicitly) by the on clause
Fig. 2 Execution model of
XMP