ceph/src/spdk/dpdk/lib/librte_eal/linuxapp/eal/eal_lcore.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation
   3  */
   4
   5 #include <unistd.h>
   6 #include <limits.h>
   7 #include <string.h>
   8 #include <dirent.h>
   9
  10 #include <rte_log.h>
  11 #include <rte_eal.h>
  12 #include <rte_lcore.h>
  13 #include <rte_common.h>
  14 #include <rte_string_fns.h>
  15 #include <rte_debug.h>
  16
  17 #include "eal_private.h"
  18 #include "eal_filesystem.h"
  19 #include "eal_thread.h"
  20
  21 #define SYS_CPU_DIR "/sys/devices/system/cpu/cpu%u"
  22 #define CORE_ID_FILE "topology/core_id"
  23 #define NUMA_NODE_PATH "/sys/devices/system/node"
  24
  25 /* Check if a cpu is present by the presence of the cpu information for it */
  26 int
  27 eal_cpu_detected(unsigned lcore_id)
  28 {
  29         char path[PATH_MAX];
  30         int len = snprintf(path, sizeof(path), SYS_CPU_DIR
  31                 "/"CORE_ID_FILE, lcore_id);
  32         if (len <= 0 || (unsigned)len >= sizeof(path))
  33                 return 0;
  34         if (access(path, F_OK) != 0)
  35                 return 0;
  36
  37         return 1;
  38 }
  39
  40 /*
  41  * Get CPU socket id (NUMA node) for a logical core.
  42  *
  43  * This searches each nodeX directories in /sys for the symlink for the given
  44  * lcore_id and returns the numa node where the lcore is found. If lcore is not
  45  * found on any numa node, returns zero.
  46  */
  47 unsigned
  48 eal_cpu_socket_id(unsigned lcore_id)
  49 {
  50         unsigned socket;
  51
  52         for (socket = 0; socket < RTE_MAX_NUMA_NODES; socket++) {
  53                 char path[PATH_MAX];
  54
  55                 snprintf(path, sizeof(path), "%s/node%u/cpu%u", NUMA_NODE_PATH,
  56                                 socket, lcore_id);
  57                 if (access(path, F_OK) == 0)
  58                         return socket;
  59         }
  60         return 0;
  61 }
  62
  63 /* Get the cpu core id value from the /sys/.../cpuX core_id value */
  64 unsigned
  65 eal_cpu_core_id(unsigned lcore_id)
  66 {
  67         char path[PATH_MAX];
  68         unsigned long id;
  69
  70         int len = snprintf(path, sizeof(path), SYS_CPU_DIR "/%s", lcore_id, CORE_ID_FILE);
  71         if (len <= 0 || (unsigned)len >= sizeof(path))
  72                 goto err;
  73         if (eal_parse_sysfs_value(path, &id) != 0)
  74                 goto err;
  75         return (unsigned)id;
  76
  77 err:
  78         RTE_LOG(ERR, EAL, "Error reading core id value from %s "
  79                         "for lcore %u - assuming core 0\n", SYS_CPU_DIR, lcore_id);
  80         return 0;
  81 }