root/tools/perf/util/ordered-events.c

DEFINITIONS

1. queue_event
2. __dup_event
3. dup_event
4. __free_dup_event
5. free_dup_event
6. ordered_events__new_event
7. ordered_events__delete
8. ordered_events__queue
9. do_flush
10. __ordered_events__flush
11. ordered_events__flush
12. ordered_events__flush_time
13. ordered_events__first_time
14. ordered_events__init
15. ordered_events_buffer__free
16. ordered_events__free
17. ordered_events__reinit

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <inttypes.h>
   4 #include <linux/list.h>
   5 #include <linux/compiler.h>
   6 #include <linux/string.h>
   7 #include "ordered-events.h"
   8 #include "session.h"
   9 #include "asm/bug.h"
  10 #include "debug.h"
  11 #include "ui/progress.h"
  12 
  13 #define pr_N(n, fmt, ...) \
  14         eprintf(n, debug_ordered_events, fmt, ##__VA_ARGS__)
  15 
  16 #define pr(fmt, ...) pr_N(1, pr_fmt(fmt), ##__VA_ARGS__)
  17 
  18 static void queue_event(struct ordered_events *oe, struct ordered_event *new)
  19 {
  20         struct ordered_event *last = oe->last;
  21         u64 timestamp = new->timestamp;
  22         struct list_head *p;
  23 
  24         ++oe->nr_events;
  25         oe->last = new;
  26 
  27         pr_oe_time2(timestamp, "queue_event nr_events %u\n", oe->nr_events);
  28 
  29         if (!last) {
  30                 list_add(&new->list, &oe->events);
  31                 oe->max_timestamp = timestamp;
  32                 return;
  33         }
  34 
  35         /*
  36          * last event might point to some random place in the list as it's
  37          * the last queued event. We expect that the new event is close to
  38          * this.
  39          */
  40         if (last->timestamp <= timestamp) {
  41                 while (last->timestamp <= timestamp) {
  42                         p = last->list.next;
  43                         if (p == &oe->events) {
  44                                 list_add_tail(&new->list, &oe->events);
  45                                 oe->max_timestamp = timestamp;
  46                                 return;
  47                         }
  48                         last = list_entry(p, struct ordered_event, list);
  49                 }
  50                 list_add_tail(&new->list, &last->list);
  51         } else {
  52                 while (last->timestamp > timestamp) {
  53                         p = last->list.prev;
  54                         if (p == &oe->events) {
  55                                 list_add(&new->list, &oe->events);
  56                                 return;
  57                         }
  58                         last = list_entry(p, struct ordered_event, list);
  59                 }
  60                 list_add(&new->list, &last->list);
  61         }
  62 }
  63 
  64 static union perf_event *__dup_event(struct ordered_events *oe,
  65                                      union perf_event *event)
  66 {
  67         union perf_event *new_event = NULL;
  68 
  69         if (oe->cur_alloc_size < oe->max_alloc_size) {
  70                 new_event = memdup(event, event->header.size);
  71                 if (new_event)
  72                         oe->cur_alloc_size += event->header.size;
  73         }
  74 
  75         return new_event;
  76 }
  77 
  78 static union perf_event *dup_event(struct ordered_events *oe,
  79                                    union perf_event *event)
  80 {
  81         return oe->copy_on_queue ? __dup_event(oe, event) : event;
  82 }
  83 
  84 static void __free_dup_event(struct ordered_events *oe, union perf_event *event)
  85 {
  86         if (event) {
  87                 oe->cur_alloc_size -= event->header.size;
  88                 free(event);
  89         }
  90 }
  91 
  92 static void free_dup_event(struct ordered_events *oe, union perf_event *event)
  93 {
  94         if (oe->copy_on_queue)
  95                 __free_dup_event(oe, event);
  96 }
  97 
  98 #define MAX_SAMPLE_BUFFER       (64 * 1024 / sizeof(struct ordered_event))
  99 static struct ordered_event *alloc_event(struct ordered_events *oe,
 100                                          union perf_event *event)
 101 {
 102         struct list_head *cache = &oe->cache;
 103         struct ordered_event *new = NULL;
 104         union perf_event *new_event;
 105         size_t size;
 106 
 107         new_event = dup_event(oe, event);
 108         if (!new_event)
 109                 return NULL;
 110 
 111         /*
 112          * We maintain the following scheme of buffers for ordered
 113          * event allocation:
 114          *
 115          *   to_free list -> buffer1 (64K)
 116          *                   buffer2 (64K)
 117          *                   ...
 118          *
 119          * Each buffer keeps an array of ordered events objects:
 120          *    buffer -> event[0]
 121          *              event[1]
 122          *              ...
 123          *
 124          * Each allocated ordered event is linked to one of
 125          * following lists:
 126          *   - time ordered list 'events'
 127          *   - list of currently removed events 'cache'
 128          *
 129          * Allocation of the ordered event uses the following order
 130          * to get the memory:
 131          *   - use recently removed object from 'cache' list
 132          *   - use available object in current allocation buffer
 133          *   - allocate new buffer if the current buffer is full
 134          *
 135          * Removal of ordered event object moves it from events to
 136          * the cache list.
 137          */
 138         size = sizeof(*oe->buffer) + MAX_SAMPLE_BUFFER * sizeof(*new);
 139 
 140         if (!list_empty(cache)) {
 141                 new = list_entry(cache->next, struct ordered_event, list);
 142                 list_del_init(&new->list);
 143         } else if (oe->buffer) {
 144                 new = &oe->buffer->event[oe->buffer_idx];
 145                 if (++oe->buffer_idx == MAX_SAMPLE_BUFFER)
 146                         oe->buffer = NULL;
 147         } else if ((oe->cur_alloc_size + size) < oe->max_alloc_size) {
 148                 oe->buffer = malloc(size);
 149                 if (!oe->buffer) {
 150                         free_dup_event(oe, new_event);
 151                         return NULL;
 152                 }
 153 
 154                 pr("alloc size %" PRIu64 "B (+%zu), max %" PRIu64 "B\n",
 155                    oe->cur_alloc_size, size, oe->max_alloc_size);
 156 
 157                 oe->cur_alloc_size += size;
 158                 list_add(&oe->buffer->list, &oe->to_free);
 159 
 160                 oe->buffer_idx = 1;
 161                 new = &oe->buffer->event[0];
 162         } else {
 163                 pr("allocation limit reached %" PRIu64 "B\n", oe->max_alloc_size);
 164                 return NULL;
 165         }
 166 
 167         new->event = new_event;
 168         return new;
 169 }
 170 
 171 static struct ordered_event *
 172 ordered_events__new_event(struct ordered_events *oe, u64 timestamp,
 173                     union perf_event *event)
 174 {
 175         struct ordered_event *new;
 176 
 177         new = alloc_event(oe, event);
 178         if (new) {
 179                 new->timestamp = timestamp;
 180                 queue_event(oe, new);
 181         }
 182 
 183         return new;
 184 }
 185 
 186 void ordered_events__delete(struct ordered_events *oe, struct ordered_event *event)
 187 {
 188         list_move(&event->list, &oe->cache);
 189         oe->nr_events--;
 190         free_dup_event(oe, event->event);
 191         event->event = NULL;
 192 }
 193 
 194 int ordered_events__queue(struct ordered_events *oe, union perf_event *event,
 195                           u64 timestamp, u64 file_offset)
 196 {
 197         struct ordered_event *oevent;
 198 
 199         if (!timestamp || timestamp == ~0ULL)
 200                 return -ETIME;
 201 
 202         if (timestamp < oe->last_flush) {
 203                 pr_oe_time(timestamp,      "out of order event\n");
 204                 pr_oe_time(oe->last_flush, "last flush, last_flush_type %d\n",
 205                            oe->last_flush_type);
 206 
 207                 oe->nr_unordered_events++;
 208         }
 209 
 210         oevent = ordered_events__new_event(oe, timestamp, event);
 211         if (!oevent) {
 212                 ordered_events__flush(oe, OE_FLUSH__HALF);
 213                 oevent = ordered_events__new_event(oe, timestamp, event);
 214         }
 215 
 216         if (!oevent)
 217                 return -ENOMEM;
 218 
 219         oevent->file_offset = file_offset;
 220         return 0;
 221 }
 222 
 223 static int do_flush(struct ordered_events *oe, bool show_progress)
 224 {
 225         struct list_head *head = &oe->events;
 226         struct ordered_event *tmp, *iter;
 227         u64 limit = oe->next_flush;
 228         u64 last_ts = oe->last ? oe->last->timestamp : 0ULL;
 229         struct ui_progress prog;
 230         int ret;
 231 
 232         if (!limit)
 233                 return 0;
 234 
 235         if (show_progress)
 236                 ui_progress__init(&prog, oe->nr_events, "Processing time ordered events...");
 237 
 238         list_for_each_entry_safe(iter, tmp, head, list) {
 239                 if (session_done())
 240                         return 0;
 241 
 242                 if (iter->timestamp > limit)
 243                         break;
 244                 ret = oe->deliver(oe, iter);
 245                 if (ret)
 246                         return ret;
 247 
 248                 ordered_events__delete(oe, iter);
 249                 oe->last_flush = iter->timestamp;
 250 
 251                 if (show_progress)
 252                         ui_progress__update(&prog, 1);
 253         }
 254 
 255         if (list_empty(head))
 256                 oe->last = NULL;
 257         else if (last_ts <= limit)
 258                 oe->last = list_entry(head->prev, struct ordered_event, list);
 259 
 260         if (show_progress)
 261                 ui_progress__finish();
 262 
 263         return 0;
 264 }
 265 
 266 static int __ordered_events__flush(struct ordered_events *oe, enum oe_flush how,
 267                                    u64 timestamp)
 268 {
 269         static const char * const str[] = {
 270                 "NONE",
 271                 "FINAL",
 272                 "ROUND",
 273                 "HALF ",
 274                 "TOP  ",
 275                 "TIME ",
 276         };
 277         int err;
 278         bool show_progress = false;
 279 
 280         if (oe->nr_events == 0)
 281                 return 0;
 282 
 283         switch (how) {
 284         case OE_FLUSH__FINAL:
 285                 show_progress = true;
 286                 __fallthrough;
 287         case OE_FLUSH__TOP:
 288                 oe->next_flush = ULLONG_MAX;
 289                 break;
 290 
 291         case OE_FLUSH__HALF:
 292         {
 293                 struct ordered_event *first, *last;
 294                 struct list_head *head = &oe->events;
 295 
 296                 first = list_entry(head->next, struct ordered_event, list);
 297                 last = oe->last;
 298 
 299                 /* Warn if we are called before any event got allocated. */
 300                 if (WARN_ONCE(!last || list_empty(head), "empty queue"))
 301                         return 0;
 302 
 303                 oe->next_flush  = first->timestamp;
 304                 oe->next_flush += (last->timestamp - first->timestamp) / 2;
 305                 break;
 306         }
 307 
 308         case OE_FLUSH__TIME:
 309                 oe->next_flush = timestamp;
 310                 show_progress = false;
 311                 break;
 312 
 313         case OE_FLUSH__ROUND:
 314         case OE_FLUSH__NONE:
 315         default:
 316                 break;
 317         };
 318 
 319         pr_oe_time(oe->next_flush, "next_flush - ordered_events__flush PRE  %s, nr_events %u\n",
 320                    str[how], oe->nr_events);
 321         pr_oe_time(oe->max_timestamp, "max_timestamp\n");
 322 
 323         err = do_flush(oe, show_progress);
 324 
 325         if (!err) {
 326                 if (how == OE_FLUSH__ROUND)
 327                         oe->next_flush = oe->max_timestamp;
 328 
 329                 oe->last_flush_type = how;
 330         }
 331 
 332         pr_oe_time(oe->next_flush, "next_flush - ordered_events__flush POST %s, nr_events %u\n",
 333                    str[how], oe->nr_events);
 334         pr_oe_time(oe->last_flush, "last_flush\n");
 335 
 336         return err;
 337 }
 338 
 339 int ordered_events__flush(struct ordered_events *oe, enum oe_flush how)
 340 {
 341         return __ordered_events__flush(oe, how, 0);
 342 }
 343 
 344 int ordered_events__flush_time(struct ordered_events *oe, u64 timestamp)
 345 {
 346         return __ordered_events__flush(oe, OE_FLUSH__TIME, timestamp);
 347 }
 348 
 349 u64 ordered_events__first_time(struct ordered_events *oe)
 350 {
 351         struct ordered_event *event;
 352 
 353         if (list_empty(&oe->events))
 354                 return 0;
 355 
 356         event = list_first_entry(&oe->events, struct ordered_event, list);
 357         return event->timestamp;
 358 }
 359 
 360 void ordered_events__init(struct ordered_events *oe, ordered_events__deliver_t deliver,
 361                           void *data)
 362 {
 363         INIT_LIST_HEAD(&oe->events);
 364         INIT_LIST_HEAD(&oe->cache);
 365         INIT_LIST_HEAD(&oe->to_free);
 366         oe->max_alloc_size = (u64) -1;
 367         oe->cur_alloc_size = 0;
 368         oe->deliver        = deliver;
 369         oe->data           = data;
 370 }
 371 
 372 static void
 373 ordered_events_buffer__free(struct ordered_events_buffer *buffer,
 374                             unsigned int max, struct ordered_events *oe)
 375 {
 376         if (oe->copy_on_queue) {
 377                 unsigned int i;
 378 
 379                 for (i = 0; i < max; i++)
 380                         __free_dup_event(oe, buffer->event[i].event);
 381         }
 382 
 383         free(buffer);
 384 }
 385 
 386 void ordered_events__free(struct ordered_events *oe)
 387 {
 388         struct ordered_events_buffer *buffer, *tmp;
 389 
 390         if (list_empty(&oe->to_free))
 391                 return;
 392 
 393         /*
 394          * Current buffer might not have all the events allocated
 395          * yet, we need to free only allocated ones ...
 396          */
 397         if (oe->buffer) {
 398                 list_del_init(&oe->buffer->list);
 399                 ordered_events_buffer__free(oe->buffer, oe->buffer_idx, oe);
 400         }
 401 
 402         /* ... and continue with the rest */
 403         list_for_each_entry_safe(buffer, tmp, &oe->to_free, list) {
 404                 list_del_init(&buffer->list);
 405                 ordered_events_buffer__free(buffer, MAX_SAMPLE_BUFFER, oe);
 406         }
 407 }
 408 
 409 void ordered_events__reinit(struct ordered_events *oe)
 410 {
 411         ordered_events__deliver_t old_deliver = oe->deliver;
 412 
 413         ordered_events__free(oe);
 414         memset(oe, '\0', sizeof(*oe));
 415         ordered_events__init(oe, old_deliver, oe->data);
 416 }