tools/lib/perf/cpumap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <perf/cpumap.h>
   3 #include <stdlib.h>
   4 #include <linux/refcount.h>
   5 #include <internal/cpumap.h>
   6 #include <asm/bug.h>
   7 #include <stdio.h>
   8 #include <string.h>
   9 #include <unistd.h>
  10 #include <ctype.h>
  11 #include <limits.h>
  12
  13 struct perf_cpu_map *perf_cpu_map__dummy_new(void)
  14 {
  15         struct perf_cpu_map *cpus = malloc(sizeof(*cpus) + sizeof(int));
  16
  17         if (cpus != NULL) {
  18                 cpus->nr = 1;
  19                 cpus->map[0] = -1;
  20                 refcount_set(&cpus->refcnt, 1);
  21         }
  22
  23         return cpus;
  24 }
  25
  26 static void cpu_map__delete(struct perf_cpu_map *map)
  27 {
  28         if (map) {
  29                 WARN_ONCE(refcount_read(&map->refcnt) != 0,
  30                           "cpu_map refcnt unbalanced\n");
  31                 free(map);
  32         }
  33 }
  34
  35 struct perf_cpu_map *perf_cpu_map__get(struct perf_cpu_map *map)
  36 {
  37         if (map)
  38                 refcount_inc(&map->refcnt);
  39         return map;
  40 }
  41
  42 void perf_cpu_map__put(struct perf_cpu_map *map)
  43 {
  44         if (map && refcount_dec_and_test(&map->refcnt))
  45                 cpu_map__delete(map);
  46 }
  47
  48 static struct perf_cpu_map *cpu_map__default_new(void)
  49 {
  50         struct perf_cpu_map *cpus;
  51         int nr_cpus;
  52
  53         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
  54         if (nr_cpus < 0)
  55                 return NULL;
  56
  57         cpus = malloc(sizeof(*cpus) + nr_cpus * sizeof(int));
  58         if (cpus != NULL) {
  59                 int i;
  60
  61                 for (i = 0; i < nr_cpus; ++i)
  62                         cpus->map[i] = i;
  63
  64                 cpus->nr = nr_cpus;
  65                 refcount_set(&cpus->refcnt, 1);
  66         }
  67
  68         return cpus;
  69 }
  70
  71 struct perf_cpu_map *perf_cpu_map__default_new(void)
  72 {
  73         return cpu_map__default_new();
  74 }
  75
  76 static int cmp_int(const void *a, const void *b)
  77 {
  78         return *(const int *)a - *(const int*)b;
  79 }
  80
  81 static struct perf_cpu_map *cpu_map__trim_new(int nr_cpus, int *tmp_cpus)
  82 {
  83         size_t payload_size = nr_cpus * sizeof(int);
  84         struct perf_cpu_map *cpus = malloc(sizeof(*cpus) + payload_size);
  85         int i, j;
  86
  87         if (cpus != NULL) {
  88                 memcpy(cpus->map, tmp_cpus, payload_size);
  89                 qsort(cpus->map, nr_cpus, sizeof(int), cmp_int);
  90                 /* Remove dups */
  91                 j = 0;
  92                 for (i = 0; i < nr_cpus; i++) {
  93                         if (i == 0 || cpus->map[i] != cpus->map[i - 1])
  94                                 cpus->map[j++] = cpus->map[i];
  95                 }
  96                 cpus->nr = j;
  97                 assert(j <= nr_cpus);
  98                 refcount_set(&cpus->refcnt, 1);
  99         }
 100
 101         return cpus;
 102 }
 103
 104 struct perf_cpu_map *perf_cpu_map__read(FILE *file)
 105 {
 106         struct perf_cpu_map *cpus = NULL;
 107         int nr_cpus = 0;
 108         int *tmp_cpus = NULL, *tmp;
 109         int max_entries = 0;
 110         int n, cpu, prev;
 111         char sep;
 112
 113         sep = 0;
 114         prev = -1;
 115         for (;;) {
 116                 n = fscanf(file, "%u%c", &cpu, &sep);
 117                 if (n <= 0)
 118                         break;
 119                 if (prev >= 0) {
 120                         int new_max = nr_cpus + cpu - prev - 1;
 121
 122                         WARN_ONCE(new_max >= MAX_NR_CPUS, "Perf can support %d CPUs. "
 123                                                           "Consider raising MAX_NR_CPUS\n", MAX_NR_CPUS);
 124
 125                         if (new_max >= max_entries) {
 126                                 max_entries = new_max + MAX_NR_CPUS / 2;
 127                                 tmp = realloc(tmp_cpus, max_entries * sizeof(int));
 128                                 if (tmp == NULL)
 129                                         goto out_free_tmp;
 130                                 tmp_cpus = tmp;
 131                         }
 132
 133                         while (++prev < cpu)
 134                                 tmp_cpus[nr_cpus++] = prev;
 135                 }
 136                 if (nr_cpus == max_entries) {
 137                         max_entries += MAX_NR_CPUS;
 138                         tmp = realloc(tmp_cpus, max_entries * sizeof(int));
 139                         if (tmp == NULL)
 140                                 goto out_free_tmp;
 141                         tmp_cpus = tmp;
 142                 }
 143
 144                 tmp_cpus[nr_cpus++] = cpu;
 145                 if (n == 2 && sep == '-')
 146                         prev = cpu;
 147                 else
 148                         prev = -1;
 149                 if (n == 1 || sep == '\n')
 150                         break;
 151         }
 152
 153         if (nr_cpus > 0)
 154                 cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
 155         else
 156                 cpus = cpu_map__default_new();
 157 out_free_tmp:
 158         free(tmp_cpus);
 159         return cpus;
 160 }
 161
 162 static struct perf_cpu_map *cpu_map__read_all_cpu_map(void)
 163 {
 164         struct perf_cpu_map *cpus = NULL;
 165         FILE *onlnf;
 166
 167         onlnf = fopen("/sys/devices/system/cpu/online", "r");
 168         if (!onlnf)
 169                 return cpu_map__default_new();
 170
 171         cpus = perf_cpu_map__read(onlnf);
 172         fclose(onlnf);
 173         return cpus;
 174 }
 175
 176 struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list)
 177 {
 178         struct perf_cpu_map *cpus = NULL;
 179         unsigned long start_cpu, end_cpu = 0;
 180         char *p = NULL;
 181         int i, nr_cpus = 0;
 182         int *tmp_cpus = NULL, *tmp;
 183         int max_entries = 0;
 184
 185         if (!cpu_list)
 186                 return cpu_map__read_all_cpu_map();
 187
 188         /*
 189          * must handle the case of empty cpumap to cover
 190          * TOPOLOGY header for NUMA nodes with no CPU
 191          * ( e.g., because of CPU hotplug)
 192          */
 193         if (!isdigit(*cpu_list) && *cpu_list != '\0')
 194                 goto out;
 195
 196         while (isdigit(*cpu_list)) {
 197                 p = NULL;
 198                 start_cpu = strtoul(cpu_list, &p, 0);
 199                 if (start_cpu >= INT_MAX
 200                     || (*p != '\0' && *p != ',' && *p != '-'))
 201                         goto invalid;
 202
 203                 if (*p == '-') {
 204                         cpu_list = ++p;
 205                         p = NULL;
 206                         end_cpu = strtoul(cpu_list, &p, 0);
 207
 208                         if (end_cpu >= INT_MAX || (*p != '\0' && *p != ','))
 209                                 goto invalid;
 210
 211                         if (end_cpu < start_cpu)
 212                                 goto invalid;
 213                 } else {
 214                         end_cpu = start_cpu;
 215                 }
 216
 217                 WARN_ONCE(end_cpu >= MAX_NR_CPUS, "Perf can support %d CPUs. "
 218                                                   "Consider raising MAX_NR_CPUS\n", MAX_NR_CPUS);
 219
 220                 for (; start_cpu <= end_cpu; start_cpu++) {
 221                         /* check for duplicates */
 222                         for (i = 0; i < nr_cpus; i++)
 223                                 if (tmp_cpus[i] == (int)start_cpu)
 224                                         goto invalid;
 225
 226                         if (nr_cpus == max_entries) {
 227                                 max_entries += MAX_NR_CPUS;
 228                                 tmp = realloc(tmp_cpus, max_entries * sizeof(int));
 229                                 if (tmp == NULL)
 230                                         goto invalid;
 231                                 tmp_cpus = tmp;
 232                         }
 233                         tmp_cpus[nr_cpus++] = (int)start_cpu;
 234                 }
 235                 if (*p)
 236                         ++p;
 237
 238                 cpu_list = p;
 239         }
 240
 241         if (nr_cpus > 0)
 242                 cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
 243         else if (*cpu_list != '\0')
 244                 cpus = cpu_map__default_new();
 245         else
 246                 cpus = perf_cpu_map__dummy_new();
 247 invalid:
 248         free(tmp_cpus);
 249 out:
 250         return cpus;
 251 }
 252
 253 int perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx)
 254 {
 255         if (cpus && idx < cpus->nr)
 256                 return cpus->map[idx];
 257
 258         return -1;
 259 }
 260
 261 int perf_cpu_map__nr(const struct perf_cpu_map *cpus)
 262 {
 263         return cpus ? cpus->nr : 1;
 264 }
 265
 266 bool perf_cpu_map__empty(const struct perf_cpu_map *map)
 267 {
 268         return map ? map->map[0] == -1 : true;
 269 }
 270
 271 int perf_cpu_map__idx(struct perf_cpu_map *cpus, int cpu)
 272 {
 273         int low = 0, high = cpus->nr;
 274
 275         while (low < high) {
 276                 int idx = (low + high) / 2,
 277                     cpu_at_idx = cpus->map[idx];
 278
 279                 if (cpu_at_idx == cpu)
 280                         return idx;
 281
 282                 if (cpu_at_idx > cpu)
 283                         high = idx;
 284                 else
 285                         low = idx + 1;
 286         }
 287
 288         return -1;
 289 }
 290
 291 int perf_cpu_map__max(struct perf_cpu_map *map)
 292 {
 293         // cpu_map__trim_new() qsort()s it, cpu_map__default_new() sorts it as well.
 294         return map->nr > 0 ? map->map[map->nr - 1] : -1;
 295 }
 296
 297 /*
 298  * Merge two cpumaps
 299  *
 300  * orig either gets freed and replaced with a new map, or reused
 301  * with no reference count change (similar to "realloc")
 302  * other has its reference count increased.
 303  */
 304
 305 struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig,
 306                                          struct perf_cpu_map *other)
 307 {
 308         int *tmp_cpus;
 309         int tmp_len;
 310         int i, j, k;
 311         struct perf_cpu_map *merged;
 312
 313         if (!orig && !other)
 314                 return NULL;
 315         if (!orig) {
 316                 perf_cpu_map__get(other);
 317                 return other;
 318         }
 319         if (!other)
 320                 return orig;
 321         if (orig->nr == other->nr &&
 322             !memcmp(orig->map, other->map, orig->nr * sizeof(int)))
 323                 return orig;
 324
 325         tmp_len = orig->nr + other->nr;
 326         tmp_cpus = malloc(tmp_len * sizeof(int));
 327         if (!tmp_cpus)
 328                 return NULL;
 329
 330         /* Standard merge algorithm from wikipedia */
 331         i = j = k = 0;
 332         while (i < orig->nr && j < other->nr) {
 333                 if (orig->map[i] <= other->map[j]) {
 334                         if (orig->map[i] == other->map[j])
 335                                 j++;
 336                         tmp_cpus[k++] = orig->map[i++];
 337                 } else
 338                         tmp_cpus[k++] = other->map[j++];
 339         }
 340
 341         while (i < orig->nr)
 342                 tmp_cpus[k++] = orig->map[i++];
 343
 344         while (j < other->nr)
 345                 tmp_cpus[k++] = other->map[j++];
 346         assert(k <= tmp_len);
 347
 348         merged = cpu_map__trim_new(k, tmp_cpus);
 349         free(tmp_cpus);
 350         perf_cpu_map__put(orig);
 351         return merged;
 352 }