NAME

ck_pr_fence_load — enforce partial ordering of load operations

LIBRARY

Concurrency Kit (libck, -lck)

SYNOPSIS

#include <ck_pr.h>

void
ck_pr_fence_load(void);

void
ck_pr_fence_strict_load(void);

DESCRIPTION

This function enforces the ordering of any memory load and ck_pr_load(3) operations relative to the invocation of the function. Any store operations that were committed on remote processors and received by the calling processor before the invocation of ck_pr_fence_load() is also be made visible only after a call to ck_pr_fence_load(). This function always serves as an implicit compiler barrier. On architectures with CK_MD_TSO or CK_MD_PSO specified (total store ordering and partial store ordering respectively), this operation only serves as a compiler barrier and no fence instructions will be emitted. To force the unconditional emission of a load fence, use ck_pr_fence_strict_load(). Architectures implementing CK_MD_RMO always emit a load fence.

EXAMPLE

#include <ck_pr.h>

static unsigned int a;
static unsigned int b;

void
function(void)
{
	unsigned int snapshot_a, snapshot_b;

	snapshot_a = ck_pr_load_uint(&a);

	/*
	 * Guarantee that the load from "a" completes
	 * before the load from "b".
	 */
	ck_pr_fence_load();
	snapshot_b = ck_pr_load_uint(&b);

	return;
}

RETURN VALUES

This function has no return value.