openfam::fam::fam_fence

Ensures that FAM operations issued by the calling PE thread before the fence are completed before FAM operations issued after the fence are dispatched.

Synopsis

void fam_fence(void);

Description

This method orders FAM operations (put, scatter, atomics, copy) issued by the calling PE thread before the fence to be performed before FAM operations issued by the calling PE thread after the fence. This method is non-blocking.

Input Arguments

None.

Return Values

None. Throws an exception on error.

Exceptions

Notes

Note that this method does NOT order fam_map()-enabled load/store accesses by the processor to FAM.

Example

#include <string.h>
#include <fam/fam.h>
#include <fam/fam_exception.h>
using namespace std;
using namespace openfam;

int main(void) {
	fam *myFam = new fam();
	// ... Initialization code here
	try {
		// look up the descriptor to a previously allocated data item
		// (a 50-element integer array)
		Fam_Descriptor *descriptor = myFam->fam_lookup("myItem","myRegion");
		
		// local data
		int local[] = {0,1,2,3,4};
		uint64_t indexes[] = {0, 7, 3, 5, 6};
			
		// scatter local data in myItem[0,7,3,5,6] respectively
		myFam->fam_scatter_nonblocking(local, descriptor, 5, indexes, sizeof(int));
		
		// ensure that the scatter is performed before subsequent FAM updates
		myFam->fam_fence();
		
		// now update later elements of the array in FAM
		int newLocal[] = {0,1,2,3,4,5,6,7,8,9};
		
		// update elements 11 - 20 in FAM using values in local memory
		myFam->fam_put_nonblocking(newLocal, descriptor, 10*sizeof(int), sizeof(local));
		
		// ... subsequent code here
	} catch (Fam_Exception &e) {
		printf("fam API failed: %d: %s\n", e.fam_error(), e.fam_error_msg());
	}
		
	// ... Finalization code follows
}