STAPL: stapl::runtime::concurrency Class Reference

Initializes and controls threads for shared-memory concurrency. More...

Static Public Member Functions
static void	initialize (option const &opts, const process_id pid, const unsigned npids, const unsigned int nppn)
	Initializes the concurrency layer. More...

static void	finalize (void)
	Finalizes the concurrency layer.

static unsigned int	hardware_concurrency (void) noexcept
	Returns the total number of threads available to the runtime. More...

static std::thread::id	get_master_thread_id (void) noexcept
	Returns the id of the master thread of this process.

static std::vector< unsigned int >	get_level_widths (void)
	Returns the parallelism level widths.

static unsigned int	available_levels (void) noexcept
	Returns the available parallelism levels. More...

static affinity_tag	get_affinity (void) noexcept
	Returns the affinity of the calling thread.

static hierarchical_mutex &	get_mutex (void) noexcept
	Returns the hierarchical_mutex tied to the calling thread.

static void	fork (std::function< void(unsigned int)> init, std::function< void(unsigned int)> f, const unsigned int n=1)
	Consumes the next `n` available parallelism levels and executes the given function on them. More...

Detailed Description

Initializes and controls threads for shared-memory concurrency.

Member Function Documentation

◆ initialize()

void stapl::runtime::concurrency::initialize	(	option const &	opts,
		const process_id	pid,
		const unsigned	npids,
		const unsigned int	nppn
	)

static

Initializes the concurrency layer.

The only option currently supported for the option object is STAPL_PROC_HIERARCHY that is a comma-separated value that describes the shared memory node hierarchy (e.g STAPL_PROC_HIERARCHY=2,4,2 means 2 sockets, with 4 cores each and 2 threads each).

Parameters

opts	Options to pass for initialization.
pid	Current process id.
npids	Total number of processes.
nppn	Number of processes per node.

◆ hardware_concurrency()

unsigned int stapl::runtime::concurrency::hardware_concurrency ( void )

staticnoexcept

Returns the total number of threads available to the runtime.

Warning: This value is just a hint; there might be more or less threads in absolute value.

◆ available_levels()

unsigned int stapl::runtime::concurrency::available_levels ( void )

staticnoexcept

Returns the available parallelism levels.

After each call of fork, the number of available levels decreases by n, where n is the last argument in fork.

◆ fork()

void stapl::runtime::concurrency::fork	(	std::function< void(unsigned int)>	init,
		std::function< void(unsigned int)>	f,
		const unsigned int	n = `1`
	)

static

Consumes the next n available parallelism levels and executes the given function on them.

n is either n or available_levels(), whichever is smaller. The init function is run from the main thread and is passed the size of the new parallel section while f is being passed each thread's id.