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 static int cmp_int(const void *a, const void *b)
  72 {
  73         return *(const int *)a - *(const int*)b;
  74 }
  75
  76 static struct perf_cpu_map *cpu_map__trim_new(int nr_cpus, int *tmp_cpus)
  77 {
  78         size_t payload_size = nr_cpus * sizeof(int);
  79         struct perf_cpu_map *cpus = malloc(sizeof(*cpus) + payload_size);
  80         int i, j;
  81
  82         if (cpus != NULL) {
  83                 memcpy(cpus->map, tmp_cpus, payload_size);
  84                 qsort(cpus->map, nr_cpus, sizeof(int), cmp_int);
  85                 /* Remove dups */
  86                 j = 0;
  87                 for (i = 0; i < nr_cpus; i++) {
  88                         if (i == 0 || cpus->map[i] != cpus->map[i - 1])
  89                                 cpus->map[j++] = cpus->map[i];
  90                 }
  91                 cpus->nr = j;
  92                 assert(j <= nr_cpus);
  93                 refcount_set(&cpus->refcnt, 1);
  94         }
  95
  96         return cpus;
  97 }
  98
  99 struct perf_cpu_map *perf_cpu_map__read(FILE *file)
 100 {
 101         struct perf_cpu_map *cpus = NULL;
 102         int nr_cpus = 0;
 103         int *tmp_cpus = NULL, *tmp;
 104         int max_entries = 0;
 105         int n, cpu, prev;
 106         char sep;
 107
 108         sep = 0;
 109         prev = -1;
 110         for (;;) {
 111                 n = fscanf(file, "%u%c", &cpu, &sep);
 112                 if (n <= 0)
 113                         break;
 114                 if (prev >= 0) {
 115                         int new_max = nr_cpus + cpu - prev - 1;
 116
 117                         WARN_ONCE(new_max >= MAX_NR_CPUS, "Perf can support %d CPUs. "
 118                                                           "Consider raising MAX_NR_CPUS\n", MAX_NR_CPUS);
 119
 120                         if (new_max >= max_entries) {
 121                                 max_entries = new_max + MAX_NR_CPUS / 2;
 122                                 tmp = realloc(tmp_cpus, max_entries * sizeof(int));
 123                                 if (tmp == NULL)
 124                                         goto out_free_tmp;
 125                                 tmp_cpus = tmp;
 126                         }
 127
 128                         while (++prev < cpu)
 129                                 tmp_cpus[nr_cpus++] = prev;
 130                 }
 131                 if (nr_cpus == max_entries) {
 132                         max_entries += MAX_NR_CPUS;
 133                         tmp = realloc(tmp_cpus, max_entries * sizeof(int));
 134                         if (tmp == NULL)
 135                                 goto out_free_tmp;
 136                         tmp_cpus = tmp;
 137                 }
 138
 139                 tmp_cpus[nr_cpus++] = cpu;
 140                 if (n == 2 && sep == '-')
 141                         prev = cpu;
 142                 else
 143                         prev = -1;
 144                 if (n == 1 || sep == '\n')
 145                         break;
 146         }
 147
 148         if (nr_cpus > 0)
 149                 cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
 150         else
 151                 cpus = cpu_map__default_new();
 152 out_free_tmp:
 153         free(tmp_cpus);
 154         return cpus;
 155 }
 156
 157 static struct perf_cpu_map *cpu_map__read_all_cpu_map(void)
 158 {
 159         struct perf_cpu_map *cpus = NULL;
 160         FILE *onlnf;
 161
 162         onlnf = fopen("/sys/devices/system/cpu/online", "r");
 163         if (!onlnf)
 164                 return cpu_map__default_new();
 165
 166         cpus = perf_cpu_map__read(onlnf);
 167         fclose(onlnf);
 168         return cpus;
 169 }
 170
 171 struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list)
 172 {
 173         struct perf_cpu_map *cpus = NULL;
 174         unsigned long start_cpu, end_cpu = 0;
 175         char *p = NULL;
 176         int i, nr_cpus = 0;
 177         int *tmp_cpus = NULL, *tmp;
 178         int max_entries = 0;
 179
 180         if (!cpu_list)
 181                 return cpu_map__read_all_cpu_map();
 182
 183         /*
 184          * must handle the case of empty cpumap to cover
 185          * TOPOLOGY header for NUMA nodes with no CPU
 186          * ( e.g., because of CPU hotplug)
 187          */
 188         if (!isdigit(*cpu_list) && *cpu_list != '\0')
 189                 goto out;
 190
 191         while (isdigit(*cpu_list)) {
 192                 p = NULL;
 193                 start_cpu = strtoul(cpu_list, &p, 0);
 194                 if (start_cpu >= INT_MAX
 195                     || (*p != '\0' && *p != ',' && *p != '-'))
 196                         goto invalid;
 197
 198                 if (*p == '-') {
 199                         cpu_list = ++p;
 200                         p = NULL;
 201                         end_cpu = strtoul(cpu_list, &p, 0);
 202
 203                         if (end_cpu >= INT_MAX || (*p != '\0' && *p != ','))
 204                                 goto invalid;
 205
 206                         if (end_cpu < start_cpu)
 207                                 goto invalid;
 208                 } else {
 209                         end_cpu = start_cpu;
 210                 }
 211
 212                 WARN_ONCE(end_cpu >= MAX_NR_CPUS, "Perf can support %d CPUs. "
 213                                                   "Consider raising MAX_NR_CPUS\n", MAX_NR_CPUS);
 214
 215                 for (; start_cpu <= end_cpu; start_cpu++) {
 216                         /* check for duplicates */
 217                         for (i = 0; i < nr_cpus; i++)
 218                                 if (tmp_cpus[i] == (int)start_cpu)
 219                                         goto invalid;
 220
 221                         if (nr_cpus == max_entries) {
 222                                 max_entries += MAX_NR_CPUS;
 223                                 tmp = realloc(tmp_cpus, max_entries * sizeof(int));
 224                                 if (tmp == NULL)
 225                                         goto invalid;
 226                                 tmp_cpus = tmp;
 227                         }
 228                         tmp_cpus[nr_cpus++] = (int)start_cpu;
 229                 }
 230                 if (*p)
 231                         ++p;
 232
 233                 cpu_list = p;
 234         }
 235
 236         if (nr_cpus > 0)
 237                 cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
 238         else if (*cpu_list != '\0')
 239                 cpus = cpu_map__default_new();
 240         else
 241                 cpus = perf_cpu_map__dummy_new();
 242 invalid:
 243         free(tmp_cpus);
 244 out:
 245         return cpus;
 246 }
 247
 248 int perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx)
 249 {
 250         if (cpus && idx < cpus->nr)
 251                 return cpus->map[idx];
 252
 253         return -1;
 254 }
 255
 256 int perf_cpu_map__nr(const struct perf_cpu_map *cpus)
 257 {
 258         return cpus ? cpus->nr : 1;
 259 }
 260
 261 bool perf_cpu_map__empty(const struct perf_cpu_map *map)
 262 {
 263         return map ? map->map[0] == -1 : true;
 264 }
 265
 266 int perf_cpu_map__idx(struct perf_cpu_map *cpus, int cpu)
 267 {
 268         int i;
 269
 270         for (i = 0; i < cpus->nr; ++i) {
 271                 if (cpus->map[i] == cpu)
 272                         return i;
 273         }
 274
 275         return -1;
 276 }
 277
 278 int perf_cpu_map__max(struct perf_cpu_map *map)
 279 {
 280         int i, max = -1;
 281
 282         for (i = 0; i < map->nr; i++) {
 283                 if (map->map[i] > max)
 284                         max = map->map[i];
 285         }
 286
 287         return max;
 288 }
 289
 290 /*
 291  * Merge two cpumaps
 292  *
 293  * orig either gets freed and replaced with a new map, or reused
 294  * with no reference count change (similar to "realloc")
 295  * other has its reference count increased.
 296  */
 297
 298 struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig,
 299                                          struct perf_cpu_map *other)
 300 {
 301         int *tmp_cpus;
 302         int tmp_len;
 303         int i, j, k;
 304         struct perf_cpu_map *merged;
 305
 306         if (!orig && !other)
 307                 return NULL;
 308         if (!orig) {
 309                 perf_cpu_map__get(other);
 310                 return other;
 311         }
 312         if (!other)
 313                 return orig;
 314         if (orig->nr == other->nr &&
 315             !memcmp(orig->map, other->map, orig->nr * sizeof(int)))
 316                 return orig;
 317
 318         tmp_len = orig->nr + other->nr;
 319         tmp_cpus = malloc(tmp_len * sizeof(int));
 320         if (!tmp_cpus)
 321                 return NULL;
 322
 323         /* Standard merge algorithm from wikipedia */
 324         i = j = k = 0;
 325         while (i < orig->nr && j < other->nr) {
 326                 if (orig->map[i] <= other->map[j]) {
 327                         if (orig->map[i] == other->map[j])
 328                                 j++;
 329                         tmp_cpus[k++] = orig->map[i++];
 330                 } else
 331                         tmp_cpus[k++] = other->map[j++];
 332         }
 333
 334         while (i < orig->nr)
 335                 tmp_cpus[k++] = orig->map[i++];
 336
 337         while (j < other->nr)
 338                 tmp_cpus[k++] = other->map[j++];
 339         assert(k <= tmp_len);
 340
 341         merged = cpu_map__trim_new(k, tmp_cpus);
 342         free(tmp_cpus);
 343         perf_cpu_map__put(orig);
 344         return merged;
 345 }