xref: /openbmc/linux/tools/perf/util/ordered-events.c (revision b8d312aa) 
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 
12 #define pr_N(n, fmt, ...) \
13 	eprintf(n, debug_ordered_events, fmt, ##__VA_ARGS__)
14 
15 #define pr(fmt, ...) pr_N(1, pr_fmt(fmt), ##__VA_ARGS__)
16 
17 static void queue_event(struct ordered_events *oe, struct ordered_event *new)
18 {
19 	struct ordered_event *last = oe->last;
20 	u64 timestamp = new->timestamp;
21 	struct list_head *p;
22 
23 	++oe->nr_events;
24 	oe->last = new;
25 
26 	pr_oe_time2(timestamp, "queue_event nr_events %u\n", oe->nr_events);
27 
28 	if (!last) {
29 		list_add(&new->list, &oe->events);
30 		oe->max_timestamp = timestamp;
31 		return;
32 	}
33 
34 	/*
35 	 * last event might point to some random place in the list as it's
36 	 * the last queued event. We expect that the new event is close to
37 	 * this.
38 	 */
39 	if (last->timestamp <= timestamp) {
40 		while (last->timestamp <= timestamp) {
41 			p = last->list.next;
42 			if (p == &oe->events) {
43 				list_add_tail(&new->list, &oe->events);
44 				oe->max_timestamp = timestamp;
45 				return;
46 			}
47 			last = list_entry(p, struct ordered_event, list);
48 		}
49 		list_add_tail(&new->list, &last->list);
50 	} else {
51 		while (last->timestamp > timestamp) {
52 			p = last->list.prev;
53 			if (p == &oe->events) {
54 				list_add(&new->list, &oe->events);
55 				return;
56 			}
57 			last = list_entry(p, struct ordered_event, list);
58 		}
59 		list_add(&new->list, &last->list);
60 	}
61 }
62 
63 static union perf_event *__dup_event(struct ordered_events *oe,
64 				     union perf_event *event)
65 {
66 	union perf_event *new_event = NULL;
67 
68 	if (oe->cur_alloc_size < oe->max_alloc_size) {
69 		new_event = memdup(event, event->header.size);
70 		if (new_event)
71 			oe->cur_alloc_size += event->header.size;
72 	}
73 
74 	return new_event;
75 }
76 
77 static union perf_event *dup_event(struct ordered_events *oe,
78 				   union perf_event *event)
79 {
80 	return oe->copy_on_queue ? __dup_event(oe, event) : event;
81 }
82 
83 static void __free_dup_event(struct ordered_events *oe, union perf_event *event)
84 {
85 	if (event) {
86 		oe->cur_alloc_size -= event->header.size;
87 		free(event);
88 	}
89 }
90 
91 static void free_dup_event(struct ordered_events *oe, union perf_event *event)
92 {
93 	if (oe->copy_on_queue)
94 		__free_dup_event(oe, event);
95 }
96 
97 #define MAX_SAMPLE_BUFFER	(64 * 1024 / sizeof(struct ordered_event))
98 static struct ordered_event *alloc_event(struct ordered_events *oe,
99 					 union perf_event *event)
100 {
101 	struct list_head *cache = &oe->cache;
102 	struct ordered_event *new = NULL;
103 	union perf_event *new_event;
104 	size_t size;
105 
106 	new_event = dup_event(oe, event);
107 	if (!new_event)
108 		return NULL;
109 
110 	/*
111 	 * We maintain the following scheme of buffers for ordered
112 	 * event allocation:
113 	 *
114 	 *   to_free list -> buffer1 (64K)
115 	 *                   buffer2 (64K)
116 	 *                   ...
117 	 *
118 	 * Each buffer keeps an array of ordered events objects:
119 	 *    buffer -> event[0]
120 	 *              event[1]
121 	 *              ...
122 	 *
123 	 * Each allocated ordered event is linked to one of
124 	 * following lists:
125 	 *   - time ordered list 'events'
126 	 *   - list of currently removed events 'cache'
127 	 *
128 	 * Allocation of the ordered event uses the following order
129 	 * to get the memory:
130 	 *   - use recently removed object from 'cache' list
131 	 *   - use available object in current allocation buffer
132 	 *   - allocate new buffer if the current buffer is full
133 	 *
134 	 * Removal of ordered event object moves it from events to
135 	 * the cache list.
136 	 */
137 	size = sizeof(*oe->buffer) + MAX_SAMPLE_BUFFER * sizeof(*new);
138 
139 	if (!list_empty(cache)) {
140 		new = list_entry(cache->next, struct ordered_event, list);
141 		list_del_init(&new->list);
142 	} else if (oe->buffer) {
143 		new = &oe->buffer->event[oe->buffer_idx];
144 		if (++oe->buffer_idx == MAX_SAMPLE_BUFFER)
145 			oe->buffer = NULL;
146 	} else if ((oe->cur_alloc_size + size) < oe->max_alloc_size) {
147 		oe->buffer = malloc(size);
148 		if (!oe->buffer) {
149 			free_dup_event(oe, new_event);
150 			return NULL;
151 		}
152 
153 		pr("alloc size %" PRIu64 "B (+%zu), max %" PRIu64 "B\n",
154 		   oe->cur_alloc_size, size, oe->max_alloc_size);
155 
156 		oe->cur_alloc_size += size;
157 		list_add(&oe->buffer->list, &oe->to_free);
158 
159 		oe->buffer_idx = 1;
160 		new = &oe->buffer->event[0];
161 	} else {
162 		pr("allocation limit reached %" PRIu64 "B\n", oe->max_alloc_size);
163 		return NULL;
164 	}
165 
166 	new->event = new_event;
167 	return new;
168 }
169 
170 static struct ordered_event *
171 ordered_events__new_event(struct ordered_events *oe, u64 timestamp,
172 		    union perf_event *event)
173 {
174 	struct ordered_event *new;
175 
176 	new = alloc_event(oe, event);
177 	if (new) {
178 		new->timestamp = timestamp;
179 		queue_event(oe, new);
180 	}
181 
182 	return new;
183 }
184 
185 void ordered_events__delete(struct ordered_events *oe, struct ordered_event *event)
186 {
187 	list_move(&event->list, &oe->cache);
188 	oe->nr_events--;
189 	free_dup_event(oe, event->event);
190 	event->event = NULL;
191 }
192 
193 int ordered_events__queue(struct ordered_events *oe, union perf_event *event,
194 			  u64 timestamp, u64 file_offset)
195 {
196 	struct ordered_event *oevent;
197 
198 	if (!timestamp || timestamp == ~0ULL)
199 		return -ETIME;
200 
201 	if (timestamp < oe->last_flush) {
202 		pr_oe_time(timestamp,      "out of order event\n");
203 		pr_oe_time(oe->last_flush, "last flush, last_flush_type %d\n",
204 			   oe->last_flush_type);
205 
206 		oe->nr_unordered_events++;
207 	}
208 
209 	oevent = ordered_events__new_event(oe, timestamp, event);
210 	if (!oevent) {
211 		ordered_events__flush(oe, OE_FLUSH__HALF);
212 		oevent = ordered_events__new_event(oe, timestamp, event);
213 	}
214 
215 	if (!oevent)
216 		return -ENOMEM;
217 
218 	oevent->file_offset = file_offset;
219 	return 0;
220 }
221 
222 static int do_flush(struct ordered_events *oe, bool show_progress)
223 {
224 	struct list_head *head = &oe->events;
225 	struct ordered_event *tmp, *iter;
226 	u64 limit = oe->next_flush;
227 	u64 last_ts = oe->last ? oe->last->timestamp : 0ULL;
228 	struct ui_progress prog;
229 	int ret;
230 
231 	if (!limit)
232 		return 0;
233 
234 	if (show_progress)
235 		ui_progress__init(&prog, oe->nr_events, "Processing time ordered events...");
236 
237 	list_for_each_entry_safe(iter, tmp, head, list) {
238 		if (session_done())
239 			return 0;
240 
241 		if (iter->timestamp > limit)
242 			break;
243 		ret = oe->deliver(oe, iter);
244 		if (ret)
245 			return ret;
246 
247 		ordered_events__delete(oe, iter);
248 		oe->last_flush = iter->timestamp;
249 
250 		if (show_progress)
251 			ui_progress__update(&prog, 1);
252 	}
253 
254 	if (list_empty(head))
255 		oe->last = NULL;
256 	else if (last_ts <= limit)
257 		oe->last = list_entry(head->prev, struct ordered_event, list);
258 
259 	if (show_progress)
260 		ui_progress__finish();
261 
262 	return 0;
263 }
264 
265 static int __ordered_events__flush(struct ordered_events *oe, enum oe_flush how,
266 				   u64 timestamp)
267 {
268 	static const char * const str[] = {
269 		"NONE",
270 		"FINAL",
271 		"ROUND",
272 		"HALF ",
273 		"TOP  ",
274 		"TIME ",
275 	};
276 	int err;
277 	bool show_progress = false;
278 
279 	if (oe->nr_events == 0)
280 		return 0;
281 
282 	switch (how) {
283 	case OE_FLUSH__FINAL:
284 		show_progress = true;
285 		__fallthrough;
286 	case OE_FLUSH__TOP:
287 		oe->next_flush = ULLONG_MAX;
288 		break;
289 
290 	case OE_FLUSH__HALF:
291 	{
292 		struct ordered_event *first, *last;
293 		struct list_head *head = &oe->events;
294 
295 		first = list_entry(head->next, struct ordered_event, list);
296 		last = oe->last;
297 
298 		/* Warn if we are called before any event got allocated. */
299 		if (WARN_ONCE(!last || list_empty(head), "empty queue"))
300 			return 0;
301 
302 		oe->next_flush  = first->timestamp;
303 		oe->next_flush += (last->timestamp - first->timestamp) / 2;
304 		break;
305 	}
306 
307 	case OE_FLUSH__TIME:
308 		oe->next_flush = timestamp;
309 		show_progress = false;
310 		break;
311 
312 	case OE_FLUSH__ROUND:
313 	case OE_FLUSH__NONE:
314 	default:
315 		break;
316 	};
317 
318 	pr_oe_time(oe->next_flush, "next_flush - ordered_events__flush PRE  %s, nr_events %u\n",
319 		   str[how], oe->nr_events);
320 	pr_oe_time(oe->max_timestamp, "max_timestamp\n");
321 
322 	err = do_flush(oe, show_progress);
323 
324 	if (!err) {
325 		if (how == OE_FLUSH__ROUND)
326 			oe->next_flush = oe->max_timestamp;
327 
328 		oe->last_flush_type = how;
329 	}
330 
331 	pr_oe_time(oe->next_flush, "next_flush - ordered_events__flush POST %s, nr_events %u\n",
332 		   str[how], oe->nr_events);
333 	pr_oe_time(oe->last_flush, "last_flush\n");
334 
335 	return err;
336 }
337 
338 int ordered_events__flush(struct ordered_events *oe, enum oe_flush how)
339 {
340 	return __ordered_events__flush(oe, how, 0);
341 }
342 
343 int ordered_events__flush_time(struct ordered_events *oe, u64 timestamp)
344 {
345 	return __ordered_events__flush(oe, OE_FLUSH__TIME, timestamp);
346 }
347 
348 u64 ordered_events__first_time(struct ordered_events *oe)
349 {
350 	struct ordered_event *event;
351 
352 	if (list_empty(&oe->events))
353 		return 0;
354 
355 	event = list_first_entry(&oe->events, struct ordered_event, list);
356 	return event->timestamp;
357 }
358 
359 void ordered_events__init(struct ordered_events *oe, ordered_events__deliver_t deliver,
360 			  void *data)
361 {
362 	INIT_LIST_HEAD(&oe->events);
363 	INIT_LIST_HEAD(&oe->cache);
364 	INIT_LIST_HEAD(&oe->to_free);
365 	oe->max_alloc_size = (u64) -1;
366 	oe->cur_alloc_size = 0;
367 	oe->deliver	   = deliver;
368 	oe->data	   = data;
369 }
370 
371 static void
372 ordered_events_buffer__free(struct ordered_events_buffer *buffer,
373 			    unsigned int max, struct ordered_events *oe)
374 {
375 	if (oe->copy_on_queue) {
376 		unsigned int i;
377 
378 		for (i = 0; i < max; i++)
379 			__free_dup_event(oe, buffer->event[i].event);
380 	}
381 
382 	free(buffer);
383 }
384 
385 void ordered_events__free(struct ordered_events *oe)
386 {
387 	struct ordered_events_buffer *buffer, *tmp;
388 
389 	if (list_empty(&oe->to_free))
390 		return;
391 
392 	/*
393 	 * Current buffer might not have all the events allocated
394 	 * yet, we need to free only allocated ones ...
395 	 */
396 	if (oe->buffer) {
397 		list_del_init(&oe->buffer->list);
398 		ordered_events_buffer__free(oe->buffer, oe->buffer_idx, oe);
399 	}
400 
401 	/* ... and continue with the rest */
402 	list_for_each_entry_safe(buffer, tmp, &oe->to_free, list) {
403 		list_del_init(&buffer->list);
404 		ordered_events_buffer__free(buffer, MAX_SAMPLE_BUFFER, oe);
405 	}
406 }
407 
408 void ordered_events__reinit(struct ordered_events *oe)
409 {
410 	ordered_events__deliver_t old_deliver = oe->deliver;
411 
412 	ordered_events__free(oe);
413 	memset(oe, '\0', sizeof(*oe));
414 	ordered_events__init(oe, old_deliver, oe->data);
415 }
416