cpu_mapping.c

/* @version $Id: cpu_mapping.c 4548 2013-12-07 16:05:16Z bcagri $ */
 
#include <stdio.h>  /* FILE, fopen */
#include <stdlib.h> /* exit, perror */
#include <unistd.h> /* sysconf */
#include <numaif.h> /* get_mempolicy() */
 
#include "cpu_mapping.h"
 
#define MAX_NODES 512
 
#ifdef __cplusplus
namespace eth_hashjoin {
#endif // __cplusplus
 
static int inited = 0;
static int max_cpus;
static int node_mapping[MAX_NODES];
 
static int
init_mappings_from_file()
{
    FILE * cfg;
        int i;
 
    cfg = fopen(CUSTOM_CPU_MAPPING, "r");
    if (cfg!=NULL) {
        if(fscanf(cfg, "%d", &max_cpus) <= 0) {
            perror("Could not parse input!\n");
        }
 
        for(i = 0; i < max_cpus; i++){
            if(fscanf(cfg, "%d", &node_mapping[i]) <= 0) {
                perror("Could not parse input!\n");
            }
        }
 
        fclose(cfg);
        return 1;
    }
 
 
    /* perror("Custom cpu mapping file not found!\n"); */
    return 0;
}
 
static void 
init_mappings()
{
    if( init_mappings_from_file() == 0 ) {
        int i;
        
        max_cpus  = sysconf(_SC_NPROCESSORS_ONLN);
        for(i = 0; i < max_cpus; i++){
            node_mapping[i] = i;
        }
    }
}
 
int 
get_cpu_id(int thread_id) 
{
    if(!inited){
        init_mappings();
        inited = 1;
    }
 
    return node_mapping[thread_id % max_cpus];
}
 
/* TODO: These are just place-holder implementations. */
#define INTEL_E5 1
 
static int numa[][16] = {
    {0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60},
    {1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57, 61},
    {2, 6, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58, 62},
    {3, 7, 11, 15, 19, 23, 27, 31, 35, 39, 43, 47, 51, 55, 59, 63} };
 
int
get_numa_id(int mytid)
{
#if INTEL_E5
    int ret = 0;
 
    for(int i = 0; i < 4; i++)
        for(int j = 0; j < 16; j++)
            if(numa[i][j] == mytid){
                ret = i;
                break;
            }
    
    return ret;
#else
    return 0;
#endif
}
 
int
get_num_numa_regions(void)
{
    /* TODO: FIXME automate it from the system config. */
#if INTEL_E5
    return 4;
#else
    return 1;
#endif
}
 
int 
get_numa_node_of_address(void * ptr)
{
    int numa_node = -1;
    get_mempolicy(&numa_node, NULL, 0, ptr, MPOL_F_NODE | MPOL_F_ADDR);
    return numa_node;
}
 
#ifdef __cplusplus
} // namespace eth_hashjoin
#endif // __cplusplus