cpumap.c

Go to the documentation of this file.

// SPDX-License-Identifier: GPL-2.0
#include "util.h"
#include <api/fs/fs.h>
#include "../perf.h"
#include "cpumap.h"
#include <assert.h>
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <linux/bitmap.h>
#include "asm/bug.h"

#include "sane_ctype.h"

static int max_cpu_num;
static int max_present_cpu_num;
static int max_node_num;
static int *cpunode_map;

static struct cpu_map *cpu_map__default_new(void)
{
    struct cpu_map *cpus;
    int nr_cpus;

    nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
    if (nr_cpus < 0)
        return NULL;

    cpus = malloc(sizeof(*cpus) + nr_cpus * sizeof(int));
    if (cpus != NULL) {
        int i;
        for (i = 0; i < nr_cpus; ++i)
            cpus->map[i] = i;

        cpus->nr = nr_cpus;
        refcount_set(&cpus->refcnt, 1);
    }

    return cpus;
}

static struct cpu_map *cpu_map__trim_new(int nr_cpus, int *tmp_cpus)
{
    size_t payload_size = nr_cpus * sizeof(int);
    struct cpu_map *cpus = malloc(sizeof(*cpus) + payload_size);

    if (cpus != NULL) {
        cpus->nr = nr_cpus;
        memcpy(cpus->map, tmp_cpus, payload_size);
        refcount_set(&cpus->refcnt, 1);
    }

    return cpus;
}

struct cpu_map *cpu_map__read(FILE *file)
{
    struct cpu_map *cpus = NULL;
    int nr_cpus = 0;
    int *tmp_cpus = NULL, *tmp;
    int max_entries = 0;
    int n, cpu, prev;
    char sep;

    sep = 0;
    prev = -1;
    for (;;) {
        n = fscanf(file, "%u%c", &cpu, &sep);
        if (n <= 0)
            break;
        if (prev >= 0) {
            int new_max = nr_cpus + cpu - prev - 1;

            if (new_max >= max_entries) {
                max_entries = new_max + MAX_NR_CPUS / 2;
                tmp = realloc(tmp_cpus, max_entries * sizeof(int));
                if (tmp == NULL)
                    goto out_free_tmp;
                tmp_cpus = tmp;
            }

            while (++prev < cpu)
                tmp_cpus[nr_cpus++] = prev;
        }
        if (nr_cpus == max_entries) {
            max_entries += MAX_NR_CPUS;
            tmp = realloc(tmp_cpus, max_entries * sizeof(int));
            if (tmp == NULL)
                goto out_free_tmp;
            tmp_cpus = tmp;
        }

        tmp_cpus[nr_cpus++] = cpu;
        if (n == 2 && sep == '-')
            prev = cpu;
        else
            prev = -1;
        if (n == 1 || sep == '\n')
            break;
    }

    if (nr_cpus > 0)
        cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
    else
        cpus = cpu_map__default_new();
out_free_tmp:
    free(tmp_cpus);
    return cpus;
}

static struct cpu_map *cpu_map__read_all_cpu_map(void)
{
    struct cpu_map *cpus = NULL;
    FILE *onlnf;

    onlnf = fopen("/sys/devices/system/cpu/online", "r");
    if (!onlnf)
        return cpu_map__default_new();

    cpus = cpu_map__read(onlnf);
    fclose(onlnf);
    return cpus;
}

struct cpu_map *cpu_map__new(const char *cpu_list)
{
    struct cpu_map *cpus = NULL;
    unsigned long start_cpu, end_cpu = 0;
    char *p = NULL;
    int i, nr_cpus = 0;
    int *tmp_cpus = NULL, *tmp;
    int max_entries = 0;

    if (!cpu_list)
        return cpu_map__read_all_cpu_map();

    if (!isdigit(*cpu_list))
        goto out;

    while (isdigit(*cpu_list)) {
        p = NULL;
        start_cpu = strtoul(cpu_list, &p, 0);
        if (start_cpu >= INT_MAX
            || (*p != '\0' && *p != ',' && *p != '-'))
            goto invalid;

        if (*p == '-') {
            cpu_list = ++p;
            p = NULL;
            end_cpu = strtoul(cpu_list, &p, 0);

            if (end_cpu >= INT_MAX || (*p != '\0' && *p != ','))
                goto invalid;

            if (end_cpu < start_cpu)
                goto invalid;
        } else {
            end_cpu = start_cpu;
        }

        for (; start_cpu <= end_cpu; start_cpu++) {
            /* check for duplicates */
            for (i = 0; i < nr_cpus; i++)
                if (tmp_cpus[i] == (int)start_cpu)
                    goto invalid;

            if (nr_cpus == max_entries) {
                max_entries += MAX_NR_CPUS;
                tmp = realloc(tmp_cpus, max_entries * sizeof(int));
                if (tmp == NULL)
                    goto invalid;
                tmp_cpus = tmp;
            }
            tmp_cpus[nr_cpus++] = (int)start_cpu;
        }
        if (*p)
            ++p;

        cpu_list = p;
    }

    if (nr_cpus > 0)
        cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
    else
        cpus = cpu_map__default_new();
invalid:
    free(tmp_cpus);
out:
    return cpus;
}

static struct cpu_map *cpu_map__from_entries(struct cpu_map_entries *cpus)
{
    struct cpu_map *map;

    map = cpu_map__empty_new(cpus->nr);
    if (map) {
        unsigned i;

        for (i = 0; i < cpus->nr; i++) {
            /*
             * Special treatment for -1, which is not real cpu number,
             * and we need to use (int) -1 to initialize map[i],
             * otherwise it would become 65535.
             */
            if (cpus->cpu[i] == (u16) -1)
                map->map[i] = -1;
            else
                map->map[i] = (int) cpus->cpu[i];
        }
    }

    return map;
}

static struct cpu_map *cpu_map__from_mask(struct cpu_map_mask *mask)
{
    struct cpu_map *map;
    int nr, nbits = mask->nr * mask->long_size * BITS_PER_BYTE;

    nr = bitmap_weight(mask->mask, nbits);

    map = cpu_map__empty_new(nr);
    if (map) {
        int cpu, i = 0;

        for_each_set_bit(cpu, mask->mask, nbits)
            map->map[i++] = cpu;
    }
    return map;

}

struct cpu_map *cpu_map__new_data(struct cpu_map_data *data)
{
    if (data->type == PERF_CPU_MAP__CPUS)
        return cpu_map__from_entries((struct cpu_map_entries *)data->data);
    else
        return cpu_map__from_mask((struct cpu_map_mask *)data->data);
}

size_t cpu_map__fprintf(struct cpu_map *map, FILE *fp)
{
#define BUFSIZE 1024
    char buf[BUFSIZE];

    cpu_map__snprint(map, buf, sizeof(buf));
    return fprintf(fp, "%s\n", buf);
#undef BUFSIZE
}

struct cpu_map *cpu_map__dummy_new(void)
{
    struct cpu_map *cpus = malloc(sizeof(*cpus) + sizeof(int));

    if (cpus != NULL) {
        cpus->nr = 1;
        cpus->map[0] = -1;
        refcount_set(&cpus->refcnt, 1);
    }

    return cpus;
}

struct cpu_map *cpu_map__empty_new(int nr)
{
    struct cpu_map *cpus = malloc(sizeof(*cpus) + sizeof(int) * nr);

    if (cpus != NULL) {
        int i;

        cpus->nr = nr;
        for (i = 0; i < nr; i++)
            cpus->map[i] = -1;

        refcount_set(&cpus->refcnt, 1);
    }

    return cpus;
}

static void cpu_map__delete(struct cpu_map *map)
{
    if (map) {
        WARN_ONCE(refcount_read(&map->refcnt) != 0,
              "cpu_map refcnt unbalanced\n");
        free(map);
    }
}

struct cpu_map *cpu_map__get(struct cpu_map *map)
{
    if (map)
        refcount_inc(&map->refcnt);
    return map;
}

void cpu_map__put(struct cpu_map *map)
{
    if (map && refcount_dec_and_test(&map->refcnt))
        cpu_map__delete(map);
}

static int cpu__get_topology_int(int cpu, const char *name, int *value)
{
    char path[PATH_MAX];

    snprintf(path, PATH_MAX,
        "devices/system/cpu/cpu%d/topology/%s", cpu, name);

    return sysfs__read_int(path, value);
}

int cpu_map__get_socket_id(int cpu)
{
    int value, ret = cpu__get_topology_int(cpu, "physical_package_id", &value);
    return ret ?: value;
}

int cpu_map__get_socket(struct cpu_map *map, int idx, void *data __maybe_unused)
{
    int cpu;

    if (idx > map->nr)
        return -1;

    cpu = map->map[idx];

    return cpu_map__get_socket_id(cpu);
}

static int cmp_ids(const void *a, const void *b)
{
    return *(int *)a - *(int *)b;
}

int cpu_map__build_map(struct cpu_map *cpus, struct cpu_map **res,
               int (*f)(struct cpu_map *map, int cpu, void *data),
               void *data)
{
    struct cpu_map *c;
    int nr = cpus->nr;
    int cpu, s1, s2;

    /* allocate as much as possible */
    c = calloc(1, sizeof(*c) + nr * sizeof(int));
    if (!c)
        return -1;

    for (cpu = 0; cpu < nr; cpu++) {
        s1 = f(cpus, cpu, data);
        for (s2 = 0; s2 < c->nr; s2++) {
            if (s1 == c->map[s2])
                break;
        }
        if (s2 == c->nr) {
            c->map[c->nr] = s1;
            c->nr++;
        }
    }
    /* ensure we process id in increasing order */
    qsort(c->map, c->nr, sizeof(int), cmp_ids);

    refcount_set(&c->refcnt, 1);
    *res = c;
    return 0;
}

int cpu_map__get_core_id(int cpu)
{
    int value, ret = cpu__get_topology_int(cpu, "core_id", &value);
    return ret ?: value;
}

int cpu_map__get_core(struct cpu_map *map, int idx, void *data)
{
    int cpu, s;

    if (idx > map->nr)
        return -1;

    cpu = map->map[idx];

    cpu = cpu_map__get_core_id(cpu);

    s = cpu_map__get_socket(map, idx, data);
    if (s == -1)
        return -1;

    /*
     * encode socket in upper 16 bits
     * core_id is relative to socket, and
     * we need a global id. So we combine
     * socket+ core id
     */
    return (s << 16) | (cpu & 0xffff);
}

int cpu_map__build_socket_map(struct cpu_map *cpus, struct cpu_map **sockp)
{
    return cpu_map__build_map(cpus, sockp, cpu_map__get_socket, NULL);
}

int cpu_map__build_core_map(struct cpu_map *cpus, struct cpu_map **corep)
{
    return cpu_map__build_map(cpus, corep, cpu_map__get_core, NULL);
}

/* setup simple routines to easily access node numbers given a cpu number */
static int get_max_num(char *path, int *max)
{
    size_t num;
    char *buf;
    int err = 0;

    if (filename__read_str(path, &buf, &num))
        return -1;

    buf[num] = '\0';

    /* start on the right, to find highest node num */
    while (--num) {
        if ((buf[num] == ',') || (buf[num] == '-')) {
            num++;
            break;
        }
    }
    if (sscanf(&buf[num], "%d", max) < 1) {
        err = -1;
        goto out;
    }

    /* convert from 0-based to 1-based */
    (*max)++;

out:
    free(buf);
    return err;
}

/* Determine highest possible cpu in the system for sparse allocation */
static void set_max_cpu_num(void)
{
    const char *mnt;
    char path[PATH_MAX];
    int ret = -1;

    /* set up default */
    max_cpu_num = 4096;
    max_present_cpu_num = 4096;

    mnt = sysfs__mountpoint();
    if (!mnt)
        goto out;

    /* get the highest possible cpu number for a sparse allocation */
    ret = snprintf(path, PATH_MAX, "%s/devices/system/cpu/possible", mnt);
    if (ret == PATH_MAX) {
        pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
        goto out;
    }

    ret = get_max_num(path, &max_cpu_num);
    if (ret)
        goto out;

    /* get the highest present cpu number for a sparse allocation */
    ret = snprintf(path, PATH_MAX, "%s/devices/system/cpu/present", mnt);
    if (ret == PATH_MAX) {
        pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
        goto out;
    }

    ret = get_max_num(path, &max_present_cpu_num);

out:
    if (ret)
        pr_err("Failed to read max cpus, using default of %d\n", max_cpu_num);
}

/* Determine highest possible node in the system for sparse allocation */
static void set_max_node_num(void)
{
    const char *mnt;
    char path[PATH_MAX];
    int ret = -1;

    /* set up default */
    max_node_num = 8;

    mnt = sysfs__mountpoint();
    if (!mnt)
        goto out;

    /* get the highest possible cpu number for a sparse allocation */
    ret = snprintf(path, PATH_MAX, "%s/devices/system/node/possible", mnt);
    if (ret == PATH_MAX) {
        pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
        goto out;
    }

    ret = get_max_num(path, &max_node_num);

out:
    if (ret)
        pr_err("Failed to read max nodes, using default of %d\n", max_node_num);
}

int cpu__max_node(void)
{
    if (unlikely(!max_node_num))
        set_max_node_num();

    return max_node_num;
}

int cpu__max_cpu(void)
{
    if (unlikely(!max_cpu_num))
        set_max_cpu_num();

    return max_cpu_num;
}

int cpu__max_present_cpu(void)
{
    if (unlikely(!max_present_cpu_num))
        set_max_cpu_num();

    return max_present_cpu_num;
}


int cpu__get_node(int cpu)
{
    if (unlikely(cpunode_map == NULL)) {
        pr_debug("cpu_map not initialized\n");
        return -1;
    }

    return cpunode_map[cpu];
}

static int init_cpunode_map(void)
{
    int i;

    set_max_cpu_num();
    set_max_node_num();

    cpunode_map = calloc(max_cpu_num, sizeof(int));
    if (!cpunode_map) {
        pr_err("%s: calloc failed\n", __func__);
        return -1;
    }

    for (i = 0; i < max_cpu_num; i++)
        cpunode_map[i] = -1;

    return 0;
}

int cpu__setup_cpunode_map(void)
{
    struct dirent *dent1, *dent2;
    DIR *dir1, *dir2;
    unsigned int cpu, mem;
    char buf[PATH_MAX];
    char path[PATH_MAX];
    const char *mnt;
    int n;

    /* initialize globals */
    if (init_cpunode_map())
        return -1;

    mnt = sysfs__mountpoint();
    if (!mnt)
        return 0;

    n = snprintf(path, PATH_MAX, "%s/devices/system/node", mnt);
    if (n == PATH_MAX) {
        pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
        return -1;
    }

    dir1 = opendir(path);
    if (!dir1)
        return 0;

    /* walk tree and setup map */
    while ((dent1 = readdir(dir1)) != NULL) {
        if (dent1->d_type != DT_DIR || sscanf(dent1->d_name, "node%u", &mem) < 1)
            continue;

        n = snprintf(buf, PATH_MAX, "%s/%s", path, dent1->d_name);
        if (n == PATH_MAX) {
            pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
            continue;
        }

        dir2 = opendir(buf);
        if (!dir2)
            continue;
        while ((dent2 = readdir(dir2)) != NULL) {
            if (dent2->d_type != DT_LNK || sscanf(dent2->d_name, "cpu%u", &cpu) < 1)
                continue;
            cpunode_map[cpu] = mem;
        }
        closedir(dir2);
    }
    closedir(dir1);
    return 0;
}

bool cpu_map__has(struct cpu_map *cpus, int cpu)
{
    return cpu_map__idx(cpus, cpu) != -1;
}

int cpu_map__idx(struct cpu_map *cpus, int cpu)
{
    int i;

    for (i = 0; i < cpus->nr; ++i) {
        if (cpus->map[i] == cpu)
            return i;
    }

    return -1;
}

int cpu_map__cpu(struct cpu_map *cpus, int idx)
{
    return cpus->map[idx];
}

size_t cpu_map__snprint(struct cpu_map *map, char *buf, size_t size)
{
    int i, cpu, start = -1;
    bool first = true;
    size_t ret = 0;

#define COMMA first ? "" : ","

    for (i = 0; i < map->nr + 1; i++) {
        bool last = i == map->nr;

        cpu = last ? INT_MAX : map->map[i];

        if (start == -1) {
            start = i;
            if (last) {
                ret += snprintf(buf + ret, size - ret,
                        "%s%d", COMMA,
                        map->map[i]);
            }
        } else if (((i - start) != (cpu - map->map[start])) || last) {
            int end = i - 1;

            if (start == end) {
                ret += snprintf(buf + ret, size - ret,
                        "%s%d", COMMA,
                        map->map[start]);
            } else {
                ret += snprintf(buf + ret, size - ret,
                        "%s%d-%d", COMMA,
                        map->map[start], map->map[end]);
            }
            first = false;
            start = i;
        }
    }

#undef COMMA

    pr_debug("cpumask list: %s\n", buf);
    return ret;
}

static char hex_char(unsigned char val)
{
    if (val < 10)
        return val + '0';
    if (val < 16)
        return val - 10 + 'a';
    return '?';
}

size_t cpu_map__snprint_mask(struct cpu_map *map, char *buf, size_t size)
{
    int i, cpu;
    char *ptr = buf;
    unsigned char *bitmap;
    int last_cpu = cpu_map__cpu(map, map->nr - 1);

    bitmap = zalloc((last_cpu + 7) / 8);
    if (bitmap == NULL) {
        buf[0] = '\0';
        return 0;
    }

    for (i = 0; i < map->nr; i++) {
        cpu = cpu_map__cpu(map, i);
        bitmap[cpu / 8] |= 1 << (cpu % 8);
    }

    for (cpu = last_cpu / 4 * 4; cpu >= 0; cpu -= 4) {
        unsigned char bits = bitmap[cpu / 8];

        if (cpu % 8)
            bits >>= 4;
        else
            bits &= 0xf;

        *ptr++ = hex_char(bits);
        if ((cpu % 32) == 0 && cpu > 0)
            *ptr++ = ',';
    }
    *ptr = '\0';
    free(bitmap);

    buf[size - 1] = '\0';
    return ptr - buf;
}