path: root/plpa-1.1/src/plpa_map.c

/*
 * Copyright (c) 2007 Cisco Systems, Inc.  All rights reserved.
 *
 * Portions of this file originally contributed by Advanced Micro
 * Devices, Inc.  See notice below.
 */
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#include "plpa_config.h"
#include "plpa.h"
#include "plpa_internal.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <limits.h>
#include <errno.h>
#include <stdlib.h>

typedef struct tuple_t_ {
    int processor_id, socket, core;
} tuple_t;

static int supported = 0;
static int num_processors = -1;
static int max_processor_num = -1;
static int num_sockets = -1;
static int max_socket_id = -1;
static int *max_core_id = NULL;
static int *num_cores = NULL;
static int max_core_id_overall = -1;
static tuple_t *map_processor_id_to_tuple = NULL;
static tuple_t ***map_tuple_to_processor_id = NULL;

static void clear_cache(void)
{
    if (NULL != max_core_id) {
        free(max_core_id);
        max_core_id = NULL;
    }
    if (NULL != num_cores) {
        free(num_cores);
        num_cores = NULL;
    }
    if (NULL != map_processor_id_to_tuple) {
        free(map_processor_id_to_tuple);
        map_processor_id_to_tuple = NULL;
    }
    if (NULL != map_tuple_to_processor_id) {
        if (NULL != map_tuple_to_processor_id[0]) {
            free(map_tuple_to_processor_id[0]);
            map_tuple_to_processor_id = NULL;
        }
        free(map_tuple_to_processor_id);
        map_tuple_to_processor_id = NULL;
    }

    num_processors = max_processor_num = -1;
    num_sockets = max_socket_id = -1;
    max_core_id_overall = -1;
}

static void load_cache(const char *sysfs_mount)
{
    int i, j, k, invalid_entry, fd;
    char path[PATH_MAX], buf[8];
    PLPA_NAME(cpu_set_t) *cores_on_sockets;
    int found;

    /* Check for the parent directory */
    sprintf(path, "%s/devices/system/cpu", sysfs_mount);
    if (access(path, R_OK|X_OK)) {
        return;
    }

    /* Go through and find the max processor ID */
    for (num_processors = max_processor_num = i = 0; 
         i < PLPA_BITMASK_CPU_MAX; ++i) {
        sprintf(path, "%s/devices/system/cpu/cpu%d", sysfs_mount, i);
        if (0 != access(path, (R_OK | X_OK))) {
            max_processor_num = i - 1;
            break;
        }
        ++num_processors;
    }

    /* If we found no processors, then we have no topology info */
    if (0 == num_processors) {
        clear_cache();
        return;
    }

    /* Malloc space for the first map (processor ID -> tuple).
       Include enough space for one invalid entry. */
    map_processor_id_to_tuple = malloc(sizeof(tuple_t) * 
                                       (max_processor_num + 2));
    if (NULL == map_processor_id_to_tuple) {
        return;
    }
    for (i = 0; i <= max_processor_num; ++i) {
        map_processor_id_to_tuple[i].processor_id = i;
        map_processor_id_to_tuple[i].socket = -1;
        map_processor_id_to_tuple[i].core = -1;
    }
    /* Set the invalid entry */
    invalid_entry = i;
    map_processor_id_to_tuple[invalid_entry].processor_id = -1;
    map_processor_id_to_tuple[invalid_entry].socket = -1;
    map_processor_id_to_tuple[invalid_entry].core = -1;

    /* Build a cached map of (socket,core) tuples */
    for (found = 0, i = 0; i <= max_processor_num; ++i) {
        sprintf(path, "%s/devices/system/cpu/cpu%d/topology/core_id", 
                sysfs_mount, i);
        fd = open(path, O_RDONLY);
        if ( fd < 0 ) {
            continue;
        }
        if ( read(fd, buf, 7) <= 0 ) {
            continue;
        }
        sscanf(buf, "%d", &(map_processor_id_to_tuple[i].core));
        close(fd);
        
        sprintf(path,
                "%s/devices/system/cpu/cpu%d/topology/physical_package_id",
                sysfs_mount, i);
        fd = open(path, O_RDONLY);
        if ( fd < 0 ) {
            continue;
        }
        if ( read(fd, buf, 7) <= 0 ) {
            continue;
        }
        sscanf(buf, "%d", &(map_processor_id_to_tuple[i].socket));
        close(fd);
        found = 1;
        
        /* Keep a running tab on the max socket number */
        if (map_processor_id_to_tuple[i].socket > max_socket_id) {
            max_socket_id = map_processor_id_to_tuple[i].socket;
        }
    }

    /* Now that we know the max number of sockets, allocate some
       arrays */
    max_core_id = malloc(sizeof(int) * (max_socket_id + 1));
    if (NULL == max_core_id) {
        clear_cache();
        return;
    }
    num_cores = malloc(sizeof(int) * (max_socket_id + 1));
    if (NULL == num_cores) {
        clear_cache();
        return;
    }
    for (i = 0; i <= max_socket_id; ++i) {
        num_cores[i] = -1;
        max_core_id[i] = -1;
    }

    /* Find the max core number on each socket */
    for (i = 0; i <= max_processor_num; ++i) {
        if (map_processor_id_to_tuple[i].core > 
            max_core_id[map_processor_id_to_tuple[i].socket]) {
            max_core_id[map_processor_id_to_tuple[i].socket] = 
                map_processor_id_to_tuple[i].core;
        }
        if (max_core_id[map_processor_id_to_tuple[i].socket] > 
            max_core_id_overall) {
            max_core_id_overall = 
                max_core_id[map_processor_id_to_tuple[i].socket];
        }
    }

    /* If we didn't find any core_id/physical_package_id's, then we
       don't have the topology info */
    if (!found) {
        clear_cache();
        return;
    }

    /* Go through and count the number of unique sockets found.  It
       may not be the same as max_socket_id because there may be
       "holes" -- e.g., sockets 0 and 3 are used, but sockets 1 and 2
       are empty. */
    for (j = i = 0; i <= max_socket_id; ++i) {
        if (max_core_id[i] >= 0) {
            ++j;
        }
    }
    if (j > 0) {
        num_sockets = j;
    }

    /* Count how many cores are available on each socket.  This may
       not be the same as max_core_id[socket_num] if there are
       "holes".  I don't know if holes can happen (i.e., if specific
       cores can be taken offline), but what the heck... */
    cores_on_sockets = malloc(sizeof(PLPA_NAME(cpu_set_t)) * 
                              (max_socket_id + 1));
    if (NULL == cores_on_sockets) {
        clear_cache();
        return;
    }
    for (i = 0; i <= max_socket_id; ++i) {
        PLPA_CPU_ZERO(&(cores_on_sockets[i]));
    }
    for (i = 0; i <= max_processor_num; ++i) {
        if (map_processor_id_to_tuple[i].socket >= 0) {
            PLPA_CPU_SET(map_processor_id_to_tuple[i].core,
                         &(cores_on_sockets[map_processor_id_to_tuple[i].socket]));
        }
    }
    for (i = 0; i <= max_socket_id; ++i) {
        int count = 0;
        for (j = 0; j < PLPA_BITMASK_CPU_MAX; ++j) {
            if (PLPA_CPU_ISSET(j, &(cores_on_sockets[i]))) {
                ++count;
            }
        }
        if (count > 0) {
            num_cores[i] = count;
        }
    }

    /* Now go through and build the map in the other direction:
       (socket,core) => processor_id.  This map simply points to
       entries in the other map (i.e., it's by reference instead of by
       value). */
    map_tuple_to_processor_id = malloc(sizeof(tuple_t **) *
                                       (max_socket_id + 1));
    if (NULL == map_tuple_to_processor_id) {
        clear_cache();
        return;
    }
    map_tuple_to_processor_id[0] = malloc(sizeof(tuple_t *) * 
                                          ((max_socket_id + 1) * 
                                           (max_core_id_overall + 1)));
    if (NULL == map_tuple_to_processor_id[0]) {
        clear_cache();
        return;
    }
    /* Set pointers for 2nd dimension */
    for (i = 1; i <= max_socket_id; ++i) {
        map_tuple_to_processor_id[i] = 
            map_tuple_to_processor_id[i - 1] + max_core_id_overall + 1;
    }
    /* Compute map */
    for (i = 0; i <= max_socket_id; ++i) {
        for (j = 0; j <= max_core_id_overall; ++j) {
            /* Default to the invalid entry in the other map, meaning
               that this (socket,core) combination doesn't exist
               (e.g., the core number does not exist in this socket,
               although it does exist in other sockets). */
            map_tuple_to_processor_id[i][j] = 
                &map_processor_id_to_tuple[invalid_entry];

            /* See if this (socket,core) tuple exists in the other
               map.  If so, set this entry to point to it (overriding
               the invalid entry default). */
            for (k = 0; k <= max_processor_num; ++k) {
                if (map_processor_id_to_tuple[k].socket == i &&
                    map_processor_id_to_tuple[k].core == j) {
                    map_tuple_to_processor_id[i][j] = 
                        &map_processor_id_to_tuple[k];
#if defined(PLPA_DEBUG) && PLPA_DEBUG
                    printf("Creating map: (socket %d, core %d) -> ID %d\n",
                           i, j, k);
#endif
                    break;
                }
            }
        }
    }

    supported = 1;
}

/* Internal function to setup the mapping data.  Guaranteed to be
   calling during PLPA_NAME(init), so we don't have to worry about
   thread safety here. */
int PLPA_NAME(map_init)(void)
{
    const char *sysfs_mount = "/sys";
    char *temp;

    temp = getenv("PLPA_SYSFS_MOUNT");
    if (temp) {
        sysfs_mount = temp;
    }

    load_cache(sysfs_mount);
    return 0;
}

/* Internal function to cleanup allocated memory.  Only called by one
   thread (during PLPA_NAME(finalize), so don't need to worry about
   thread safety here. */
void PLPA_NAME(map_finalize)(void)
{
    clear_cache();
}

/* Return whether this kernel supports topology information or not */
int PLPA_NAME(have_topology_information)(int *supported_arg)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* Check for bozo arguments */
    if (NULL == supported_arg) {
        return EINVAL;
    }

    *supported_arg = supported;
    return 0;
}

int PLPA_NAME(map_to_processor_id)(int socket, int core, int *processor_id)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* Check for bozo arguments */
    if (NULL == processor_id) {
        return EINVAL;
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for some invalid entries */
    if (socket < 0 || socket > max_socket_id ||
        core < 0 || core > max_core_id_overall) {
        return ENOENT;
    }
    /* If the mapping returns -1, then this is a non-existent
       socket/core combo (even though they fall within the max socket
       / max core overall values) */
    ret = map_tuple_to_processor_id[socket][core]->processor_id;
    if (-1 == ret) {
        return ENOENT;
    }

    /* Ok, all should be good -- return the mapping */
    *processor_id = ret;
    return 0;
}

int PLPA_NAME(map_to_socket_core)(int processor_id, int *socket, int *core)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* Check for bozo arguments */
    if (NULL == socket || NULL == core) {
        return EINVAL;
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for some invalid entries */
    if (processor_id < 0 || processor_id > max_processor_num) {
        return ENOENT;
    }
    ret = map_processor_id_to_tuple[processor_id].socket;
    if (-1 == ret) {
        return ENOENT;
    }

    /* Ok, all should be good -- return the mapping */
    *socket = ret;
    *core = map_processor_id_to_tuple[processor_id].core;
    return 0;
}

int PLPA_NAME(get_processor_info)(int *num_processors_arg,
                                  int *max_processor_num_arg)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* Check for bozo arguments */
    if (NULL == max_processor_num_arg || NULL == num_processors_arg) {
        return EINVAL;
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* All done */
    *num_processors_arg = num_processors;
    *max_processor_num_arg = max_processor_num;
    return 0;
}

/* Return the max socket number */
int PLPA_NAME(get_socket_info)(int *num_sockets_arg, int *max_socket_id_arg)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* Check for bozo arguments */
    if (NULL == max_socket_id_arg || NULL == num_sockets_arg) {
        return EINVAL;
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* All done */
    *num_sockets_arg = num_sockets;
    *max_socket_id_arg = max_socket_id;
    return 0;
}

/* Return the number of cores in a socket and the max core ID number */
int PLPA_NAME(get_core_info)(int socket, int *num_cores_arg, 
                             int *max_core_id_arg)
{
    int ret;

    /* Initialize if not already done so */
    if (!PLPA_NAME(initialized)) {
        if (0 != (ret = PLPA_NAME(init)())) {
            return ret;
        }
    }

    /* Check for bozo arguments */
    if (NULL == max_core_id_arg || NULL == num_cores_arg) {
        return EINVAL;
    }

    /* If this system doesn't support mapping, sorry Charlie */
    if (!supported) {
        return ENOSYS;
    }

    /* Check for some invalid entries */
    if (socket < 0 || socket > max_socket_id || -1 == max_core_id[socket]) {
        return ENOENT;
    }
    ret = num_cores[socket];
    if (-1 == ret) {
        return ENOENT;
    }

    /* All done */
    *num_cores_arg = ret;
    *max_core_id_arg = max_core_id[socket];
    return 0;
}