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