switch-tracking.c

  1// SPDX-License-Identifier: GPL-2.0
  2#include <sys/time.h>
  3#include <sys/prctl.h>
  4#include <errno.h>
  5#include <limits.h>
  6#include <time.h>
  7#include <stdlib.h>
  8#include <linux/zalloc.h>
  9#include <linux/err.h>
 10#include <perf/cpumap.h>
 11#include <perf/evlist.h>
 12#include <perf/mmap.h>
 13
 14#include "debug.h"
 15#include "parse-events.h"
 16#include "evlist.h"
 17#include "evsel.h"
 18#include "thread_map.h"
 19#include "record.h"
 20#include "tests.h"
 21#include "util/mmap.h"
 22#include "util/sample.h"
 23#include "pmus.h"
 24
 25static int spin_sleep(void)
 26{
 27	struct timeval start, now, diff, maxtime;
 28	struct timespec ts;
 29	int err, i;
 30
 31	maxtime.tv_sec = 0;
 32	maxtime.tv_usec = 50000;
 33
 34	err = gettimeofday(&start, NULL);
 35	if (err)
 36		return err;
 37
 38	/* Spin for 50ms */
 39	while (1) {
 40		for (i = 0; i < 1000; i++)
 41			barrier();
 42
 43		err = gettimeofday(&now, NULL);
 44		if (err)
 45			return err;
 46
 47		timersub(&now, &start, &diff);
 48		if (timercmp(&diff, &maxtime, > /* For checkpatch */))
 49			break;
 50	}
 51
 52	ts.tv_nsec = 50 * 1000 * 1000;
 53	ts.tv_sec = 0;
 54
 55	/* Sleep for 50ms */
 56	err = nanosleep(&ts, NULL);
 57	if (err == EINTR)
 58		err = 0;
 59
 60	return err;
 61}
 62
 63struct switch_tracking {
 64	struct evsel *switch_evsel;
 65	struct evsel *cycles_evsel;
 66	pid_t *tids;
 67	int nr_tids;
 68	int comm_seen[4];
 69	int cycles_before_comm_1;
 70	int cycles_between_comm_2_and_comm_3;
 71	int cycles_after_comm_4;
 72};
 73
 74static int check_comm(struct switch_tracking *switch_tracking,
 75		      union perf_event *event, const char *comm, int nr)
 76{
 77	if (event->header.type == PERF_RECORD_COMM &&
 78	    (pid_t)event->comm.pid == getpid() &&
 79	    (pid_t)event->comm.tid == getpid() &&
 80	    strcmp(event->comm.comm, comm) == 0) {
 81		if (switch_tracking->comm_seen[nr]) {
 82			pr_debug("Duplicate comm event\n");
 83			return -1;
 84		}
 85		switch_tracking->comm_seen[nr] = 1;
 86		pr_debug3("comm event: %s nr: %d\n", event->comm.comm, nr);
 87		return 1;
 88	}
 89	return 0;
 90}
 91
 92static int check_cpu(struct switch_tracking *switch_tracking, int cpu)
 93{
 94	int i, nr = cpu + 1;
 95
 96	if (cpu < 0)
 97		return -1;
 98
 99	if (!switch_tracking->tids) {
100		switch_tracking->tids = calloc(nr, sizeof(pid_t));
101		if (!switch_tracking->tids)
102			return -1;
103		for (i = 0; i < nr; i++)
104			switch_tracking->tids[i] = -1;
105		switch_tracking->nr_tids = nr;
106		return 0;
107	}
108
109	if (cpu >= switch_tracking->nr_tids) {
110		void *addr;
111
112		addr = realloc(switch_tracking->tids, nr * sizeof(pid_t));
113		if (!addr)
114			return -1;
115		switch_tracking->tids = addr;
116		for (i = switch_tracking->nr_tids; i < nr; i++)
117			switch_tracking->tids[i] = -1;
118		switch_tracking->nr_tids = nr;
119		return 0;
120	}
121
122	return 0;
123}
124
125static int process_sample_event(struct evlist *evlist,
126				union perf_event *event,
127				struct switch_tracking *switch_tracking)
128{
129	struct perf_sample sample;
130	struct evsel *evsel;
131	pid_t next_tid, prev_tid;
132	int cpu, err;
133
134	perf_sample__init(&sample, /*all=*/false);
135	if (evlist__parse_sample(evlist, event, &sample)) {
136		pr_debug("evlist__parse_sample failed\n");
137		err = -1;
138		goto out;
139	}
140
141	evsel = evlist__id2evsel(evlist, sample.id);
142	if (evsel == switch_tracking->switch_evsel) {
143		next_tid = evsel__intval(evsel, &sample, "next_pid");
144		prev_tid = evsel__intval(evsel, &sample, "prev_pid");
145		cpu = sample.cpu;
146		pr_debug3("sched_switch: cpu: %d prev_tid %d next_tid %d\n",
147			  cpu, prev_tid, next_tid);
148		err = check_cpu(switch_tracking, cpu);
149		if (err)
150			goto out;
151		/*
152		 * Check for no missing sched_switch events i.e. that the
153		 * evsel->core.system_wide flag has worked.
154		 */
155		if (switch_tracking->tids[cpu] != -1 &&
156		    switch_tracking->tids[cpu] != prev_tid) {
157			pr_debug("Missing sched_switch events\n");
158			err = -1;
159			goto out;
160		}
161		switch_tracking->tids[cpu] = next_tid;
162	}
163
164	if (evsel == switch_tracking->cycles_evsel) {
165		pr_debug3("cycles event\n");
166		if (!switch_tracking->comm_seen[0])
167			switch_tracking->cycles_before_comm_1 = 1;
168		if (switch_tracking->comm_seen[1] &&
169		    !switch_tracking->comm_seen[2])
170			switch_tracking->cycles_between_comm_2_and_comm_3 = 1;
171		if (switch_tracking->comm_seen[3])
172			switch_tracking->cycles_after_comm_4 = 1;
173	}
174
175	err = 0;
176out:
177	perf_sample__exit(&sample);
178	return err;
179}
180
181static int process_event(struct evlist *evlist, union perf_event *event,
182			 struct switch_tracking *switch_tracking)
183{
184	if (event->header.type == PERF_RECORD_SAMPLE)
185		return process_sample_event(evlist, event, switch_tracking);
186
187	if (event->header.type == PERF_RECORD_COMM) {
188		int err, done = 0;
189
190		err = check_comm(switch_tracking, event, "Test COMM 1", 0);
191		if (err < 0)
192			return -1;
193		done += err;
194		err = check_comm(switch_tracking, event, "Test COMM 2", 1);
195		if (err < 0)
196			return -1;
197		done += err;
198		err = check_comm(switch_tracking, event, "Test COMM 3", 2);
199		if (err < 0)
200			return -1;
201		done += err;
202		err = check_comm(switch_tracking, event, "Test COMM 4", 3);
203		if (err < 0)
204			return -1;
205		done += err;
206		if (done != 1) {
207			pr_debug("Unexpected comm event\n");
208			return -1;
209		}
210	}
211
212	return 0;
213}
214
215struct event_node {
216	struct list_head list;
217	union perf_event *event;
218	u64 event_time;
219};
220
221static int add_event(struct evlist *evlist, struct list_head *events,
222		     union perf_event *event)
223{
224	struct perf_sample sample;
225	struct event_node *node;
226
227	node = malloc(sizeof(struct event_node));
228	if (!node) {
229		pr_debug("malloc failed\n");
230		return -1;
231	}
232	node->event = event;
233	list_add(&node->list, events);
234
235	if (evlist__parse_sample(evlist, event, &sample)) {
236		pr_debug("evlist__parse_sample failed\n");
237		return -1;
238	}
239
240	if (!sample.time) {
241		pr_debug("event with no time\n");
242		return -1;
243	}
244
245	node->event_time = sample.time;
246
247	return 0;
248}
249
250static void free_event_nodes(struct list_head *events)
251{
252	struct event_node *node;
253
254	while (!list_empty(events)) {
255		node = list_entry(events->next, struct event_node, list);
256		list_del_init(&node->list);
257		free(node);
258	}
259}
260
261static int compar(const void *a, const void *b)
262{
263	const struct event_node *nodea = a;
264	const struct event_node *nodeb = b;
265	s64 cmp = nodea->event_time - nodeb->event_time;
266
267	return cmp < 0 ? -1 : (cmp > 0 ? 1 : 0);
268}
269
270static int process_events(struct evlist *evlist,
271			  struct switch_tracking *switch_tracking)
272{
273	union perf_event *event;
274	unsigned pos, cnt = 0;
275	LIST_HEAD(events);
276	struct event_node *events_array, *node;
277	struct mmap *md;
278	int i, ret;
279
280	for (i = 0; i < evlist->core.nr_mmaps; i++) {
281		md = &evlist->mmap[i];
282		if (perf_mmap__read_init(&md->core) < 0)
283			continue;
284
285		while ((event = perf_mmap__read_event(&md->core)) != NULL) {
286			cnt += 1;
287			ret = add_event(evlist, &events, event);
288			 perf_mmap__consume(&md->core);
289			if (ret < 0)
290				goto out_free_nodes;
291		}
292		perf_mmap__read_done(&md->core);
293	}
294
295	events_array = calloc(cnt, sizeof(struct event_node));
296	if (!events_array) {
297		pr_debug("calloc failed\n");
298		ret = -1;
299		goto out_free_nodes;
300	}
301
302	pos = 0;
303	list_for_each_entry(node, &events, list)
304		events_array[pos++] = *node;
305
306	qsort(events_array, cnt, sizeof(struct event_node), compar);
307
308	for (pos = 0; pos < cnt; pos++) {
309		ret = process_event(evlist, events_array[pos].event,
310				    switch_tracking);
311		if (ret < 0)
312			goto out_free;
313	}
314
315	ret = 0;
316out_free:
317	pr_debug("%u events recorded\n", cnt);
318	free(events_array);
319out_free_nodes:
320	free_event_nodes(&events);
321	return ret;
322}
323
324/**
325 * test__switch_tracking - test using sched_switch and tracking events.
326 *
327 * This function implements a test that checks that sched_switch events and
328 * tracking events can be recorded for a workload (current process) using the
329 * evsel->core.system_wide and evsel->tracking flags (respectively) with other events
330 * sometimes enabled or disabled.
331 */
332static int test__switch_tracking(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
333{
334	const char *sched_switch = "sched:sched_switch";
335	const char *cycles = "cpu-cycles:u";
336	struct switch_tracking switch_tracking = { .tids = NULL, };
337	struct record_opts opts = {
338		.mmap_pages	     = UINT_MAX,
339		.user_freq	     = UINT_MAX,
340		.user_interval	     = ULLONG_MAX,
341		.freq		     = 4000,
342		.target		     = {
343			.uses_mmap   = true,
344		},
345	};
346	struct perf_thread_map *threads = NULL;
347	struct perf_cpu_map *cpus = NULL;
348	struct evlist *evlist = NULL;
349	struct evsel *evsel, *cpu_clocks_evsel, *cycles_evsel;
350	struct evsel *switch_evsel, *tracking_evsel;
351	const char *comm;
352	int err = -1;
353
354	threads = thread_map__new_by_tid(getpid());
355	if (!threads) {
356		pr_debug("thread_map__new failed!\n");
357		goto out_err;
358	}
359
360	cpus = perf_cpu_map__new_online_cpus();
361	if (!cpus) {
362		pr_debug("perf_cpu_map__new failed!\n");
363		goto out_err;
364	}
365
366	evlist = evlist__new();
367	if (!evlist) {
368		pr_debug("evlist__new failed!\n");
369		goto out_err;
370	}
371
372	perf_evlist__set_maps(&evlist->core, cpus, threads);
373
374	/* First event */
375	err = parse_event(evlist, "cpu-clock:u");
376	if (err) {
377		pr_debug("Failed to parse event dummy:u\n");
378		goto out_err;
379	}
380
381	cpu_clocks_evsel = evlist__last(evlist);
382
383	/* Second event */
384	err = parse_event(evlist, cycles);
385	if (err) {
386		pr_debug("Failed to parse event %s\n", cycles);
387		goto out_err;
388	}
389
390	cycles_evsel = evlist__last(evlist);
391
392	/* Third event */
393	if (!evlist__can_select_event(evlist, sched_switch)) {
394		pr_debug("No sched_switch\n");
395		err = 0;
396		goto out;
397	}
398
399	switch_evsel = evlist__add_sched_switch(evlist, true);
400	if (IS_ERR(switch_evsel)) {
401		err = PTR_ERR(switch_evsel);
402		pr_debug("Failed to create event %s\n", sched_switch);
403		goto out_err;
404	}
405
406	switch_evsel->immediate = true;
407
408	/* Test moving an event to the front */
409	if (cycles_evsel == evlist__first(evlist)) {
410		pr_debug("cycles event already at front");
411		goto out_err;
412	}
413	evlist__to_front(evlist, cycles_evsel);
414	if (cycles_evsel != evlist__first(evlist)) {
415		pr_debug("Failed to move cycles event to front");
416		goto out_err;
417	}
418
419	evsel__set_sample_bit(cycles_evsel, CPU);
420	evsel__set_sample_bit(cycles_evsel, TIME);
421
422	/* Fourth event */
423	err = parse_event(evlist, "dummy:u");
424	if (err) {
425		pr_debug("Failed to parse event dummy:u\n");
426		goto out_err;
427	}
428
429	tracking_evsel = evlist__last(evlist);
430
431	evlist__set_tracking_event(evlist, tracking_evsel);
432
433	tracking_evsel->core.attr.freq = 0;
434	tracking_evsel->core.attr.sample_period = 1;
435
436	evsel__set_sample_bit(tracking_evsel, TIME);
437
438	/* Config events */
439	evlist__config(evlist, &opts, NULL);
440
441	/* Check moved event is still at the front */
442	if (cycles_evsel != evlist__first(evlist)) {
443		pr_debug("Front event no longer at front");
444		goto out_err;
445	}
446
447	/* Check tracking event is tracking */
448	if (!tracking_evsel->core.attr.mmap || !tracking_evsel->core.attr.comm) {
449		pr_debug("Tracking event not tracking\n");
450		goto out_err;
451	}
452
453	/* Check non-tracking events are not tracking */
454	evlist__for_each_entry(evlist, evsel) {
455		if (evsel != tracking_evsel) {
456			if (evsel->core.attr.mmap || evsel->core.attr.comm) {
457				pr_debug("Non-tracking event is tracking\n");
458				goto out_err;
459			}
460		}
461	}
462
463	if (evlist__open(evlist) < 0) {
464		pr_debug("Not supported\n");
465		err = 0;
466		goto out;
467	}
468
469	err = evlist__mmap(evlist, UINT_MAX);
470	if (err) {
471		pr_debug("evlist__mmap failed!\n");
472		goto out_err;
473	}
474
475	evlist__enable(evlist);
476
477	err = evsel__disable(cpu_clocks_evsel);
478	if (err) {
479		pr_debug("perf_evlist__disable_event failed!\n");
480		goto out_err;
481	}
482
483	err = spin_sleep();
484	if (err) {
485		pr_debug("spin_sleep failed!\n");
486		goto out_err;
487	}
488
489	comm = "Test COMM 1";
490	err = prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0);
491	if (err) {
492		pr_debug("PR_SET_NAME failed!\n");
493		goto out_err;
494	}
495
496	err = evsel__disable(cycles_evsel);
497	if (err) {
498		pr_debug("perf_evlist__disable_event failed!\n");
499		goto out_err;
500	}
501
502	comm = "Test COMM 2";
503	err = prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0);
504	if (err) {
505		pr_debug("PR_SET_NAME failed!\n");
506		goto out_err;
507	}
508
509	err = spin_sleep();
510	if (err) {
511		pr_debug("spin_sleep failed!\n");
512		goto out_err;
513	}
514
515	comm = "Test COMM 3";
516	err = prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0);
517	if (err) {
518		pr_debug("PR_SET_NAME failed!\n");
519		goto out_err;
520	}
521
522	err = evsel__enable(cycles_evsel);
523	if (err) {
524		pr_debug("perf_evlist__disable_event failed!\n");
525		goto out_err;
526	}
527
528	comm = "Test COMM 4";
529	err = prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0);
530	if (err) {
531		pr_debug("PR_SET_NAME failed!\n");
532		goto out_err;
533	}
534
535	err = spin_sleep();
536	if (err) {
537		pr_debug("spin_sleep failed!\n");
538		goto out_err;
539	}
540
541	evlist__disable(evlist);
542
543	switch_tracking.switch_evsel = switch_evsel;
544	switch_tracking.cycles_evsel = cycles_evsel;
545
546	err = process_events(evlist, &switch_tracking);
547
548	zfree(&switch_tracking.tids);
549
550	if (err)
551		goto out_err;
552
553	/* Check all 4 comm events were seen i.e. that evsel->tracking works */
554	if (!switch_tracking.comm_seen[0] || !switch_tracking.comm_seen[1] ||
555	    !switch_tracking.comm_seen[2] || !switch_tracking.comm_seen[3]) {
556		pr_debug("Missing comm events\n");
557		goto out_err;
558	}
559
560	/* Check cycles event got enabled */
561	if (!switch_tracking.cycles_before_comm_1) {
562		pr_debug("Missing cycles events\n");
563		goto out_err;
564	}
565
566	/* Check cycles event got disabled */
567	if (switch_tracking.cycles_between_comm_2_and_comm_3) {
568		pr_debug("cycles events even though event was disabled\n");
569		goto out_err;
570	}
571
572	/* Check cycles event got enabled again */
573	if (!switch_tracking.cycles_after_comm_4) {
574		pr_debug("Missing cycles events\n");
575		goto out_err;
576	}
577out:
578	if (evlist) {
579		evlist__disable(evlist);
580		evlist__delete(evlist);
581	}
582	perf_cpu_map__put(cpus);
583	perf_thread_map__put(threads);
584
585	return err;
586
587out_err:
588	err = -1;
589	goto out;
590}
591
592DEFINE_SUITE_EXCLUSIVE("Track with sched_switch", switch_tracking);