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/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2010-2014 Intel Corporation
*/
#include <unistd.h>
#include <limits.h>
#include <rte_log.h>
#include "eal_private.h"
#include "eal_filesystem.h"
#include "eal_thread.h"
#define SYS_CPU_DIR "/sys/devices/system/cpu/cpu%u"
#define CORE_ID_FILE "topology/core_id"
#define NUMA_NODE_PATH "/sys/devices/system/node"
/* Check if a cpu is present by the presence of the cpu information for it */
int
eal_cpu_detected(unsigned lcore_id)
{
char path[PATH_MAX];
int len = snprintf(path, sizeof(path), SYS_CPU_DIR
"/"CORE_ID_FILE, lcore_id);
if (len <= 0 || (unsigned)len >= sizeof(path))
return 0;
if (access(path, F_OK) != 0)
return 0;
return 1;
}
/*
* Get CPU socket id (NUMA node) for a logical core.
*
* This searches each nodeX directories in /sys for the symlink for the given
* lcore_id and returns the numa node where the lcore is found. If lcore is not
* found on any numa node, returns zero.
*/
unsigned
eal_cpu_socket_id(unsigned lcore_id)
{
unsigned socket;
for (socket = 0; socket < RTE_MAX_NUMA_NODES; socket++) {
char path[PATH_MAX];
snprintf(path, sizeof(path), "%s/node%u/cpu%u", NUMA_NODE_PATH,
socket, lcore_id);
if (access(path, F_OK) == 0)
return socket;
}
return 0;
}
/* Get the cpu core id value from the /sys/.../cpuX core_id value */
unsigned
eal_cpu_core_id(unsigned lcore_id)
{
char path[PATH_MAX];
unsigned long id;
int len = snprintf(path, sizeof(path), SYS_CPU_DIR "/%s", lcore_id, CORE_ID_FILE);
if (len <= 0 || (unsigned)len >= sizeof(path))
goto err;
if (eal_parse_sysfs_value(path, &id) != 0)
goto err;
return (unsigned)id;
err:
RTE_LOG(ERR, EAL, "Error reading core id value from %s "
"for lcore %u - assuming core 0\n", SYS_CPU_DIR, lcore_id);
return 0;
}
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