cray_upc_sheap_info

Date:

04-03-2014

NAME

cray_upc_sheap_info - Returns symmetric heap usage information

SYNOPSIS

#include <upc_cray.h>

shared void *cray_upc_sheap_info( int value );

IMPLEMENTATION

Cray Linux Environment (CLE)

DESCRIPTION

The cray_upc_sheap_info() function returns symmetric heap usage information depending on input value, which may be CRAY_UPC_SHEAP_IS_FIXED, CRAY_UPC_CURR_SIZE, CRAY_UPC_SHEAP_MAX_SIZE, or CRAY_UPC_SHEAP_HIGH_WATER, defined in upc_cray.h.

There are multiple implementations of the symmetric heap, not all of which track these statistics. The implementation used is based on the underlying network and the number of PEs and nodes in use. If PGAS_DEBUG=sheap=1 is set at runtime, then all calls to the symmetric heap are wrapped in a generic debug wrapper that tracks additional statistics even if the underlying heap implementation does not.

RETURN VALUE

Assuming that the symmetric heap information is available, the return value depends on input value as follows:

• CRAY_UPC_SHEAP_IS_FIXED

• Returns 1 if symmetric heap has a fixed size.

• CRAY_UPC_CURR_SIZE

• Returns the number of currently allocated bytes in the symmetric heap.

• CRAY_UPC_SHEAP_MAX_SIZE

• Returns the maximum size of the symmetric heap in bytes. If the symmetric heap does not have a fixed size, this is the current size possibly including free regions.

• CRAY_UPC_SHEAP_HIGH_WATER

• Returns the largest number of allocated bytes in the symmetric heap over the execution of the program up to the call. If the information is not available in the current runtime, the function returns (size_t)-1.

EXAMPLE

#include<stdio.h>
#include<upc.h>
#include<upc_cray.h>

void print_sheap_info()
{
    size_t is_fixed = cray_upc_sheap_info( CRAY_UPC_SHEAP_IS_FIXED );
    size_t curr_sz  = cray_upc_sheap_info( CRAY_UPC_SHEAP_CURR_SIZE );
    size_t max_sz   = cray_upc_sheap_info( CRAY_UPC_SHEAP_MAX_SIZE );
    size_t hw       = cray_upc_sheap_info( CRAY_UPC_SHEAP_HIGH_WATER );

    printf("  %s\n  curr:  %lu bytes\n  max:   %lu bytes\n  hw:    %lu bytes\n",
              is_fixed?"fixed":"dynamic",curr_sz,max_sz,hw);
}

int main()
{
    if ( !MYTHREAD ) {
        puts("Before allocation:");
        print_sheap_info();
    }
    shared void *p = upc_all_alloc( THREADS, 32ul * 1024ul * 1024ul );
    upc_barrier;
    if ( !MYTHREAD ) {
        puts("After allocation:");
        print_sheap_info();
    }
    upc_all_free( p );

    return 0;
}