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41 #include <rte_lcore.h>
42 #include <rte_common.h>
43 #include <rte_string_fns.h>
44 #include <rte_debug.h>
46 #include "eal_private.h"
47 #include "eal_filesystem.h"
49 #define SYS_CPU_DIR "/sys/devices/system/cpu/cpu%u"
50 #define CORE_ID_FILE "topology/core_id"
51 #define PHYS_PKG_FILE "topology/physical_package_id"
53 /* Check if a cpu is present by the presence of the cpu information for it */
55 cpu_detected(unsigned lcore_id)
58 int len = snprintf(path, sizeof(path), SYS_CPU_DIR
59 "/"CORE_ID_FILE, lcore_id);
60 if (len <= 0 || (unsigned)len >= sizeof(path))
62 if (access(path, F_OK) != 0)
68 /* Get CPU socket id (NUMA node) by reading directory
69 * /sys/devices/system/cpu/cpuX looking for symlink "nodeY"
70 * which gives the NUMA topology information.
71 * Note: physical package id != NUMA node, but we use it as a
72 * fallback for kernels which don't create a nodeY link
75 cpu_socket_id(unsigned lcore_id)
77 const char node_prefix[] = "node";
78 const size_t prefix_len = sizeof(node_prefix) - 1;
85 int len = snprintf(path, sizeof(path),
86 SYS_CPU_DIR, lcore_id);
87 if (len <= 0 || (unsigned)len >= sizeof(path))
94 while ((e = readdir(d)) != NULL) {
95 if (strncmp(e->d_name, node_prefix, prefix_len) == 0) {
96 id = strtoul(e->d_name+prefix_len, &endptr, 0);
100 if (endptr == NULL || *endptr!='\0' || endptr == e->d_name+prefix_len) {
101 RTE_LOG(WARNING, EAL, "Cannot read numa node link "
102 "for lcore %u - using physical package id instead\n",
105 len = snprintf(path, sizeof(path), SYS_CPU_DIR "/%s",
106 lcore_id, PHYS_PKG_FILE);
107 if (len <= 0 || (unsigned)len >= sizeof(path))
109 if (eal_parse_sysfs_value(path, &id) != 0)
118 RTE_LOG(ERR, EAL, "Error getting NUMA socket information from %s "
119 "for lcore %u - assuming NUMA socket 0\n", SYS_CPU_DIR, lcore_id);
123 /* Get the cpu core id value from the /sys/.../cpuX core_id value */
125 cpu_core_id(unsigned lcore_id)
130 int len = snprintf(path, sizeof(path), SYS_CPU_DIR "/%s", lcore_id, CORE_ID_FILE);
131 if (len <= 0 || (unsigned)len >= sizeof(path))
133 if (eal_parse_sysfs_value(path, &id) != 0)
138 RTE_LOG(ERR, EAL, "Error reading core id value from %s "
139 "for lcore %u - assuming core 0\n", SYS_CPU_DIR, lcore_id);
144 * Parse /sys/devices/system/cpu to get the number of physical and logical
145 * processors on the machine. The function will fill the cpu_info
149 rte_eal_cpu_init(void)
151 /* pointer to global configuration */
152 struct rte_config *config = rte_eal_get_configuration();
157 * Parse the maximum set of logical cores, detect the subset of running
158 * ones and enable them by default.
160 for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
161 lcore_config[lcore_id].detected = cpu_detected(lcore_id);
162 if (lcore_config[lcore_id].detected == 0) {
163 config->lcore_role[lcore_id] = ROLE_OFF;
166 /* By default, each detected core is enabled */
167 config->lcore_role[lcore_id] = ROLE_RTE;
168 lcore_config[lcore_id].core_id = cpu_core_id(lcore_id);
169 lcore_config[lcore_id].socket_id = cpu_socket_id(lcore_id);
170 if (lcore_config[lcore_id].socket_id >= RTE_MAX_NUMA_NODES)
171 #ifdef RTE_EAL_ALLOW_INV_SOCKET_ID
172 lcore_config[lcore_id].socket_id = 0;
174 rte_panic("Socket ID (%u) is greater than "
175 "RTE_MAX_NUMA_NODES (%d)\n",
176 lcore_config[lcore_id].socket_id, RTE_MAX_NUMA_NODES);
178 RTE_LOG(DEBUG, EAL, "Detected lcore %u as core %u on socket %u\n",
180 lcore_config[lcore_id].core_id,
181 lcore_config[lcore_id].socket_id);
184 /* Set the count of enabled logical cores of the EAL configuration */
185 config->lcore_count = count;
186 RTE_LOG(DEBUG, EAL, "Support maximum %u logical core(s) by configuration.\n",
188 RTE_LOG(DEBUG, EAL, "Detected %u lcore(s)\n", config->lcore_count);