1 // Copyright (c) 2017-2021 Apple Inc. All rights reserved.
2
3 #include <darwintest.h>
4 #include <darwintest_utils.h>
5 #include <dispatch/dispatch.h>
6 #include <inttypes.h>
7 #include <ktrace/session.h>
8 #include <ktrace/private.h>
9 #include <sys/kdebug.h>
10 #include <sys/syscall.h>
11 #include <kperf/kpc.h>
12 #include <kperf/kperf.h>
13 #include <kperfdata/kpdecode.h>
14 #include <os/assumes.h>
15 #include <stdint.h>
16 #include <sys/sysctl.h>
17
18 #include "kperf_helpers.h"
19 #include "ktrace_helpers.h"
20 #include "ktrace_meta.h"
21 #include "../drop_priv.h"
22
23 #define MAX_CPUS 64
24 #define MAX_THREADS 64
25
26 volatile static bool running_threads = true;
27
28 static void *
spinning_thread(void * semp)29 spinning_thread(void *semp)
30 {
31 T_QUIET;
32 T_ASSERT_NOTNULL(semp, "semaphore passed to thread should not be NULL");
33 dispatch_semaphore_signal(*(dispatch_semaphore_t *)semp);
34
35 while (running_threads) {
36 ;
37 }
38 return NULL;
39 }
40
41 #define PERF_STK_KHDR UINT32_C(0x25020014)
42 #define PERF_STK_UHDR UINT32_C(0x25020018)
43 #define PERF_TMR_FIRE KDBG_EVENTID(DBG_PERF, 3, 0)
44 #define PERF_TMR_HNDLR KDBG_EVENTID(DBG_PERF, 3, 2)
45 #define PERF_TMR_PEND KDBG_EVENTID(DBG_PERF, 3, 3)
46 #define PERF_TMR_SKIP KDBG_EVENTID(DBG_PERF, 3, 4)
47 #define PERF_KPC_CONFIG KDBG_EVENTID(DBG_PERF, 6, 4)
48 #define PERF_KPC_REG KDBG_EVENTID(DBG_PERF, 6, 5)
49 #define PERF_KPC_REG32 KDBG_EVENTID(DBG_PERF, 6, 7)
50 #define PERF_INSTR_DATA KDBG_EVENTID(DBG_PERF, 1, 17)
51 #define PERF_EVENT KDBG_EVENTID(DBG_PERF, 0, 0)
52 #define PERF_DISPLABEL KDBG_EVENTID(DBG_PERF, 1, 23)
53 #define PERF_DISPSAMPLE KDBG_EVENTID(DBG_PERF, 1, 10)
54
55 #define SCHED_DISPATCH KDBG_EVENTID(DBG_MACH, DBG_MACH_SCHED, MACH_DISPATCH)
56 #define SCHED_SWITCH KDBG_EVENTID(DBG_MACH, DBG_MACH_SCHED, MACH_SCHED)
57 #define SCHED_HANDOFF KDBG_EVENTID(DBG_MACH, DBG_MACH_SCHED, MACH_STACK_HANDOFF)
58 #define SCHED_IDLE KDBG_EVENTID(DBG_MACH, DBG_MACH_SCHED, MACH_IDLE)
59
60 #define MP_CPUS_CALL UINT32_C(0x1900004)
61
62 #define DISPATCH_AFTER_EVENT UINT32_C(0xfefffffc)
63 #define TIMEOUT_SECS 10
64
65 #define TIMER_PERIOD_NS (1 * NSEC_PER_MSEC)
66
67 static void
start_tracing_with_timeout(ktrace_session_t s,unsigned int timeout_secs)68 start_tracing_with_timeout(ktrace_session_t s, unsigned int timeout_secs)
69 {
70 // Only set the timeout after we've seen an event that was traced by us.
71 // This helps set a reasonable timeout after we're guaranteed to get a
72 // few events.
73 dispatch_queue_t q = dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0);
74
75 ktrace_events_single(s, DISPATCH_AFTER_EVENT,
76 ^(__unused struct trace_point *tp)
77 {
78 T_LOG("arming timer to stop tracing after %d seconds", timeout_secs);
79 dispatch_after(dispatch_time(DISPATCH_TIME_NOW,
80 timeout_secs * NSEC_PER_SEC), q, ^{
81 T_LOG("ending tracing due to timeout");
82 ktrace_end(s, 0);
83 });
84 });
85 ktrace_set_collection_interval(s, 100);
86
87 T_ASSERT_POSIX_ZERO(ktrace_start(s, q), "start ktrace");
88
89 kdebug_trace(DISPATCH_AFTER_EVENT, 0, 0, 0, 0);
90 T_LOG("trace point emitted");
91 }
92
93 static void
configure_kperf_timer_samplers(uint64_t period_ns,uint32_t samplers)94 configure_kperf_timer_samplers(uint64_t period_ns, uint32_t samplers)
95 {
96 T_SETUPBEGIN;
97
98 (void)kperf_action_count_set(1);
99 T_QUIET;
100 T_ASSERT_POSIX_SUCCESS(kperf_action_samplers_set(1, samplers),
101 NULL);
102 (void)kperf_timer_count_set(1);
103 T_QUIET;
104 T_ASSERT_POSIX_SUCCESS(kperf_timer_period_set(0,
105 kperf_ns_to_ticks(period_ns)), NULL);
106 T_QUIET;
107 T_ASSERT_POSIX_SUCCESS(kperf_timer_action_set(0, 1), NULL);
108
109 T_ASSERT_POSIX_SUCCESS(kperf_sample_set(1), "start kperf sampling");
110
111 T_SETUPEND;
112 }
113
114 static double
timestamp_secs(ktrace_session_t s,uint64_t timestamp)115 timestamp_secs(ktrace_session_t s, uint64_t timestamp)
116 {
117 uint64_t ns = 0;
118 T_QUIET;
119 T_ASSERT_POSIX_ZERO(ktrace_convert_timestamp_to_nanoseconds(s, timestamp,
120 &ns), NULL);
121 return (double)ns / NSEC_PER_SEC;
122 }
123
124 #pragma mark - timers
125
126 // Ensure that kperf is correctly sampling CPUs that are actively scheduling by
127 // bringing up threads and ensuring that threads on-core are sampled by each
128 // timer fire.
129
130 T_DECL(kperf_sample_active_cpus,
131 "make sure that kperf samples all active CPUs")
132 {
133 start_controlling_ktrace();
134
135 T_SETUPBEGIN;
136
137 int ncpus = dt_ncpu();
138 T_QUIET;
139 T_ASSERT_LT(ncpus, MAX_CPUS,
140 "only supports up to %d CPUs", MAX_CPUS);
141 T_LOG("found %d CPUs", ncpus);
142
143 int nthreads = ncpus - 1;
144 T_QUIET;
145 T_ASSERT_LT(nthreads, MAX_THREADS,
146 "only supports up to %d threads", MAX_THREADS);
147
148 static pthread_t threads[MAX_THREADS];
149
150 ktrace_session_t s = ktrace_session_create();
151 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(s, "ktrace_session_create");
152 ktrace_set_collection_interval(s, 100);
153
154 __block uint64_t nfires = 0;
155 __block uint64_t nsamples = 0;
156 static uint64_t idle_tids[MAX_CPUS] = { 0 };
157 __block double sum_saturation = 0;
158 __block uint64_t last_nsamples = 0;
159
160 // As a test debugging aid, take an additonal argument that specifies the
161 // number of fires to stop tracing after. This also turns on additional
162 // logging of scheduler trace events.
163 int stopafter = 0;
164 if (argc > 0) {
165 stopafter = atoi(argv[0]);
166 if (stopafter < 0) {
167 T_ASSERT_FAIL("argument must be positive");
168 }
169 }
170
171 static uint64_t first_timestamp = 0;
172 static uint64_t last_timestamp = 0;
173 ktrace_events_any(s, ^(struct trace_point *tp) {
174 if (first_timestamp == 0) {
175 first_timestamp = tp->timestamp;
176 }
177 last_timestamp = tp->timestamp;
178 });
179
180 ktrace_set_completion_handler(s, ^{
181 T_LOG("stopping threads");
182
183 running_threads = false;
184
185 for (int i = 0; i < nthreads; i++) {
186 T_QUIET;
187 T_ASSERT_POSIX_ZERO(pthread_join(threads[i], NULL), NULL);
188 }
189
190 double saturation = sum_saturation / nfires * 100;
191
192 T_LOG("over %.1f seconds, saw %" PRIu64 " timer fires, %" PRIu64
193 " samples, %g samples/fire, %.2f%% saturation",
194 timestamp_secs(s, last_timestamp - first_timestamp), nfires,
195 nsamples, (double)nsamples / (double)nfires, saturation);
196 T_ASSERT_GT(saturation, 95.0,
197 "saw reasonable percentage of full samples");
198
199 T_END;
200 });
201
202 // Track which threads are running on each CPU.
203 static uint64_t tids_on_cpu[MAX_CPUS] = { 0 };
204 void (^switch_cb)(struct trace_point *, const char *name) =
205 ^(struct trace_point *tp, const char *name) {
206 uint64_t new_thread = tp->arg2;
207
208 if (idle_tids[tp->cpuid] != new_thread) {
209 tids_on_cpu[tp->cpuid] = new_thread;
210 }
211
212 if (stopafter) {
213 T_LOG("%.7g: %s on %d: %llx", timestamp_secs(s, tp->timestamp),
214 name, tp->cpuid, tp->arg2);
215 }
216 };
217
218 ktrace_events_single(s, SCHED_SWITCH, ^(struct trace_point *tp) {
219 switch_cb(tp, "switch");
220 });
221 ktrace_events_single(s, SCHED_HANDOFF, ^(struct trace_point *tp) {
222 switch_cb(tp, "hndoff");
223 });
224
225 // Determine the thread IDs of the idle threads on each CPU.
226 ktrace_events_single(s, SCHED_IDLE, ^(struct trace_point *tp) {
227 if (tp->debugid & DBG_FUNC_END) {
228 return;
229 }
230 tids_on_cpu[tp->cpuid] = 0;
231 idle_tids[tp->cpuid] = tp->threadid;
232 if (stopafter) {
233 T_LOG("%.7g: idle on %d: %llx", timestamp_secs(s, tp->timestamp),
234 tp->cpuid, tp->threadid);
235 }
236 });
237
238 // On each timer fire, go through all the cores and mark any threads
239 // that should be sampled.
240
241 __block int last_fire_cpu = -1;
242 static bool sample_missing[MAX_CPUS] = { false };
243 static uint64_t tids_snap[MAX_CPUS] = { 0 };
244 __block int nexpected = 0;
245 __block int nextra = 0;
246 __block int nidles = 0;
247
248 ktrace_events_single(s, PERF_TMR_FIRE, ^(struct trace_point *tp) {
249 T_QUIET; T_ASSERT_EQ((tp->debugid & DBG_FUNC_START), 0,
250 "no timer fire start events are allowed");
251 int last_expected = nexpected;
252 nfires++;
253
254 nexpected = 0;
255 for (int i = 0; i < ncpus; i++) {
256 if (sample_missing[i]) {
257 T_LOG("missed sample on CPU %d for thread %#llx from "
258 "timer on CPU %d (expected %d samples)",
259 tp->cpuid, tids_snap[i], last_fire_cpu, last_expected);
260 sample_missing[i] = false;
261 }
262
263 if (tids_on_cpu[i] != 0) {
264 tids_snap[i] = tids_on_cpu[i];
265 sample_missing[i] = true;
266 nexpected++;
267 }
268 }
269 if (stopafter) {
270 T_LOG("%.7g: FIRE on %d: %d extra, %d idles",
271 timestamp_secs(s, tp->timestamp), tp->cpuid, nextra, nidles);
272 }
273
274 if (nfires == 1) {
275 return;
276 }
277
278 if (last_expected == 0) {
279 sum_saturation += 1;
280 } else {
281 sum_saturation += (double)(nsamples - last_nsamples) /
282 last_expected;
283 }
284 last_nsamples = nsamples;
285 nextra = 0;
286 nidles = 0;
287
288 T_QUIET;
289 T_ASSERT_LT((int)tp->cpuid, ncpus,
290 "timer fire should not occur on an IOP");
291 last_fire_cpu = (int)tp->cpuid;
292
293 if (stopafter && (uint64_t)stopafter == nfires) {
294 ktrace_end(s, 1);
295 }
296 });
297
298 // On the timer handler for each CPU, unset the missing sample bitmap.
299
300 ktrace_events_single(s, PERF_TMR_HNDLR, ^(struct trace_point *tp) {
301 nsamples++;
302 if ((int)tp->cpuid > ncpus) {
303 // Skip IOPs; they're not scheduling any relevant threads.
304 return;
305 }
306
307 if (!sample_missing[tp->cpuid] && idle_tids[tp->cpuid] != 0) {
308 T_LOG("sampled additional thread %llx on CPU %d", tp->threadid,
309 tp->cpuid);
310 nextra++;
311 }
312 if (tp->threadid == idle_tids[tp->cpuid]) {
313 T_LOG("sampled idle thread on CPU %d", tp->cpuid);
314 nidles++;
315 }
316 sample_missing[tp->cpuid] = false;
317 });
318
319 configure_kperf_timer_samplers(TIMER_PERIOD_NS, KPERF_SAMPLER_KSTACK);
320
321 T_SETUPEND;
322
323 start_tracing_with_timeout(s, TIMEOUT_SECS);
324
325 // Create threads to bring up all of the CPUs.
326
327 dispatch_semaphore_t thread_spinning = dispatch_semaphore_create(0);
328
329 for (int i = 0; i < nthreads; i++) {
330 T_QUIET;
331 T_ASSERT_POSIX_ZERO(
332 pthread_create(&threads[i], NULL, &spinning_thread,
333 &thread_spinning), NULL);
334 dispatch_semaphore_wait(thread_spinning, DISPATCH_TIME_FOREVER);
335 }
336
337 T_LOG("spun up %d thread%s", nthreads, nthreads == 1 ? "" : "s");
338
339 dispatch_main();
340 }
341
342 #define FIRES_THRESHOLD (5000)
343
344 T_DECL(kperf_timer_fires_enough_times,
345 "ensure the correct number of timers fire in a period of time")
346 {
347 start_controlling_ktrace();
348
349 dispatch_semaphore_t thread_spinning = dispatch_semaphore_create(0);
350
351 ktrace_session_t s = ktrace_session_create();
352 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(s, "ktrace_session_create");
353 ktrace_set_collection_interval(s, 100);
354
355 __block uint64_t nfires = 0;
356 __block uint64_t first_fire_ns = 0;
357 __block uint64_t last_fire_ns = 0;
358
359 int ncpus = dt_ncpu();
360
361 ktrace_events_single(s, PERF_TMR_FIRE, ^(struct trace_point *tp) {
362 nfires++;
363 if (first_fire_ns == 0) {
364 ktrace_convert_timestamp_to_nanoseconds(s, tp->timestamp,
365 &first_fire_ns);
366 }
367 ktrace_convert_timestamp_to_nanoseconds(s, tp->timestamp,
368 &last_fire_ns);
369
370 T_QUIET; T_ASSERT_LT((int)tp->cpuid, ncpus,
371 "timer fire should not occur on an IOP");
372 if (nfires >= FIRES_THRESHOLD) {
373 ktrace_end(s, 1);
374 }
375 });
376
377 configure_kperf_timer_samplers(TIMER_PERIOD_NS, KPERF_SAMPLER_KSTACK);
378
379 pthread_t thread;
380 T_QUIET;
381 T_ASSERT_POSIX_ZERO(pthread_create(&thread, NULL, &spinning_thread,
382 &thread_spinning), NULL);
383 dispatch_semaphore_wait(thread_spinning, DISPATCH_TIME_FOREVER);
384
385 ktrace_set_completion_handler(s, ^{
386 running_threads = false;
387
388 double duration_secs = (double)(last_fire_ns - first_fire_ns) /
389 NSEC_PER_SEC;
390 T_LOG("stopping thread after %.2f seconds", duration_secs);
391
392 T_QUIET; T_ASSERT_POSIX_ZERO(pthread_join(thread, NULL), NULL);
393
394 T_LOG("saw %" PRIu64 " timer fires (%g fires/second)", nfires,
395 (double)nfires / (double)duration_secs);
396 double expected_nfires = duration_secs * NSEC_PER_SEC / TIMER_PERIOD_NS;
397 T_LOG("expecting %g timer fires", expected_nfires);
398 double nfires_seen_pct = expected_nfires / nfires * 100;
399 T_ASSERT_GT(nfires_seen_pct, 95.0,
400 "saw reasonable number of missed timer fires");
401 T_ASSERT_LT(nfires_seen_pct, 105.0,
402 "saw reasonable number of extra timer fires");
403
404 T_END;
405 });
406
407 start_tracing_with_timeout(s, TIMEOUT_SECS);
408
409 dispatch_main();
410 }
411
412 // kperf_timer_not_oversampling ensures that the profiling timer fires are
413 // spaced apart by the programmed timer period. Otherwise, tools that rely on
414 // sample count as a proxy for CPU usage will over-estimate.
415
416 #define FIRE_PERIOD_THRESHOLD_NS \
417 (TIMER_PERIOD_NS - (uint64_t)(TIMER_PERIOD_NS * 0.05))
418
419 struct cirq {
420 unsigned int nslots;
421 unsigned int tail_slot;
422 unsigned int slot_size;
423 };
424
425 #define CIRQ_INIT(TYPE, NSLOTS) \
426 (struct cirq){ \
427 .nslots = NSLOTS, .tail_slot = 0, .slot_size = sizeof(TYPE), \
428 }
429
430 static inline void *
cirq_get(struct cirq * cq,unsigned int i)431 cirq_get(struct cirq *cq, unsigned int i)
432 {
433 return (char *)cq + sizeof(*cq) + (cq->slot_size * i);
434 }
435
436 static void *
cirq_top(void * vcq)437 cirq_top(void *vcq)
438 {
439 struct cirq *cq = vcq;
440 unsigned int tail_slot = cq->tail_slot;
441 unsigned int top_slot = (tail_slot > 0 ? tail_slot : cq->nslots) - 1;
442 return cirq_get(cq, top_slot);
443 }
444
445 static void *
cirq_push(void * vcq)446 cirq_push(void *vcq)
447 {
448 struct cirq *cq = vcq;
449 unsigned int tail_slot = cq->tail_slot;
450 unsigned int next_slot = tail_slot == cq->nslots - 1 ? 0 : tail_slot + 1;
451 cq->tail_slot = next_slot;
452 return cirq_get(cq, tail_slot);
453 }
454
455 static void
456 cirq_for(void *vcq, void (^iter)(void *elt))
457 {
458 struct cirq *cq = vcq;
459 for (unsigned int i = cq->tail_slot; i < cq->nslots; i++) {
460 iter(cirq_get(cq, i));
461 }
462 for (unsigned int i = 0; i < cq->tail_slot; i++) {
463 iter(cirq_get(cq, i));
464 }
465 }
466
467 #define HISTORY_LEN 5
468
469 struct instval {
470 uint64_t iv_instant_ns;
471 uint64_t iv_val;
472 };
473
474 struct cirq_instval {
475 struct cirq cq;
476 struct instval elts[HISTORY_LEN];
477 };
478
479 struct cirq_u64 {
480 struct cirq cq;
481 uint64_t elts[HISTORY_LEN];
482 };
483
484 struct cpu_oversample {
485 struct cirq_instval timer_latencies;
486 struct cirq_instval fire_latencies;
487 };
488
489 static void
cpu_oversample_log(struct cpu_oversample * cpu,unsigned int cpuid)490 cpu_oversample_log(struct cpu_oversample *cpu, unsigned int cpuid)
491 {
492 T_LOG("CPU %d timer latencies:", cpuid);
493 __block int i = -HISTORY_LEN;
494 cirq_for(&cpu->timer_latencies, ^(void *viv) {
495 struct instval *iv = viv;
496 T_LOG("\t%llu timer latency %d: %llu", iv->iv_instant_ns, i,
497 iv->iv_val);
498 i++;
499 });
500
501 T_LOG("CPU %d fire latencies:", cpuid);
502 i = -HISTORY_LEN;
503 cirq_for(&cpu->fire_latencies, ^(void *viv) {
504 struct instval *iv = viv;
505 T_LOG("\t%llu fire latency %d: %llu", iv->iv_instant_ns, i, iv->iv_val);
506 i++;
507 });
508 }
509
510 T_DECL(kperf_timer_not_oversampling,
511 "ensure that time between fires is long enough")
512 {
513 start_controlling_ktrace();
514
515 ktrace_session_t s = ktrace_session_create();
516 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(s, "ktrace_session_create");
517 // Try not to perturb the system with more work.
518 ktrace_set_collection_interval(s, 1000);
519 __block uint64_t nfires = 0;
520 __block uint64_t first_fire_ns = 0;
521 __block uint64_t last_fire_ns = 0;
522 __block unsigned int last_fire_cpuid = 0;
523
524 int ncpus = dt_ncpu();
525 T_QUIET; T_ASSERT_GT(ncpus, 0, "should see positive number of CPUs");
526
527 struct cpu_oversample *per_cpu = calloc((unsigned int)ncpus,
528 sizeof(per_cpu[0]));
529 T_QUIET; T_WITH_ERRNO;
530 T_ASSERT_NOTNULL(per_cpu, "allocated timer latency tracking");
531 for (int i = 0; i < ncpus; i++) {
532 per_cpu[i].timer_latencies.cq = CIRQ_INIT(struct instval, HISTORY_LEN);
533 per_cpu[i].fire_latencies.cq = CIRQ_INIT(struct instval, HISTORY_LEN);
534 }
535
536 __block bool in_stackshot = false;
537 __block uint64_t last_stackshot_ns = 0;
538
539 // Stackshots are the primary source of interrupt latency on the system.
540 ktrace_events_single(s, KDBG_EVENTID(DBG_BSD, DBG_BSD_EXCP_SC,
541 SYS_stack_snapshot_with_config), ^(struct trace_point *tp) {
542 bool start = tp->debugid & DBG_FUNC_START;
543 uint64_t cur_ns = relns_from_abs(s, tp->timestamp);
544 T_LOG("%llu: %s stackshot syscall from process %s",
545 cur_ns, start ? "start" : "finish", tp->command);
546 in_stackshot = start;
547 if (!start) {
548 last_stackshot_ns = cur_ns;
549 }
550 });
551
552 struct cirq_u64 *fire_times = calloc(1, sizeof(*fire_times));
553 T_ASSERT_NOTNULL(fire_times, "allocated fire time tracking");
554 fire_times->cq = CIRQ_INIT(uint64_t, HISTORY_LEN);
555
556 // Track the decrementer's latency values to find any unexpectedly long
557 // interrupt latencies that could affect the firing cadence.
558 ktrace_events_single(s, MACHDBG_CODE(DBG_MACH_EXCP_DECI, 0),
559 ^(struct trace_point *tp) {
560 uint64_t cur_ns = relns_from_abs(s, tp->timestamp);
561 uint64_t latency_ns = ns_from_abs(s, 0 - tp->arg1);
562 struct instval *latency = cirq_push(&per_cpu[tp->cpuid].timer_latencies);
563 latency->iv_instant_ns = cur_ns;
564 latency->iv_val = latency_ns;
565 });
566
567 ktrace_events_single(s, PERF_TMR_FIRE, ^(struct trace_point *tp) {
568 T_QUIET; T_ASSERT_LT((int)tp->cpuid, ncpus,
569 "timer fire should not occur on an IOP");
570
571 nfires++;
572 uint64_t cur_ns = relns_from_abs(s, tp->timestamp);
573 uint64_t *fire_ns = cirq_push(fire_times);
574 *fire_ns = cur_ns;
575
576 struct cpu_oversample *cur_cpu = &per_cpu[tp->cpuid];
577 struct instval *last_timer_latency = cirq_top(
578 &cur_cpu->timer_latencies);
579 uint64_t timer_latency_ns = last_timer_latency->iv_val;
580
581 if (first_fire_ns == 0) {
582 first_fire_ns = cur_ns;
583 } else {
584 struct cpu_oversample *last_cpu = &per_cpu[last_fire_cpuid];
585 struct instval *last_latency = cirq_top(&last_cpu->fire_latencies);
586 uint64_t last_fire_latency_ns = last_latency->iv_val;
587
588 if (timer_latency_ns > TIMER_PERIOD_NS / 4) {
589 T_LOG("%llu: long timer latency at fire: %llu", cur_ns,
590 timer_latency_ns);
591 }
592
593 // Long interrupt latencies will cause the timer to miss its fire
594 // time and report a fire past when it should have, making the next
595 // period too short. Keep track of the latency as a leeway
596 // adjustment for the subsequent fire.
597 uint64_t fire_period_ns = cur_ns - last_fire_ns;
598 uint64_t fire_period_adj_ns = fire_period_ns +
599 last_fire_latency_ns + timer_latency_ns;
600 bool too_short = fire_period_adj_ns < FIRE_PERIOD_THRESHOLD_NS;
601 if (too_short) {
602 T_LOG("%llu: period of timer fire %llu is %llu + %llu + %llu = "
603 "%llu < %llu",
604 cur_ns, nfires, fire_period_ns, last_fire_latency_ns,
605 timer_latency_ns, fire_period_adj_ns,
606 FIRE_PERIOD_THRESHOLD_NS);
607
608 T_LOG("short profile timer fired on CPU %d", tp->cpuid);
609 cpu_oversample_log(cur_cpu, tp->cpuid);
610
611 if (cur_cpu == last_cpu) {
612 T_LOG("fired back-to-back on CPU %d", tp->cpuid);
613 } else {
614 T_LOG("previous profile timer fired on CPU %d",
615 last_fire_cpuid);
616 cpu_oversample_log(last_cpu, last_fire_cpuid);
617 }
618
619 T_LOG("profile timer fires:");
620 cirq_for(fire_times, ^(void *vu64) {
621 T_LOG("\tfire: %llu", *(uint64_t *)vu64);
622 });
623 if (nfires < (unsigned int)ncpus) {
624 T_LOG("ignoring timer fire %llu as context may be missing",
625 nfires);
626 } else {
627 if (in_stackshot) {
628 T_LOG("skipping assertion because stackshot is "
629 "happening");
630 } else if (last_stackshot_ns != 0 &&
631 cur_ns > last_stackshot_ns &&
632 cur_ns - last_stackshot_ns < TIMER_PERIOD_NS) {
633 T_LOG("skipping assertion because stackshot happened "
634 "%" PRIu64 "ns ago",
635 cur_ns - last_stackshot_ns);
636 } else {
637 T_ASSERT_FAIL("profiling period is shorter than "
638 "expected with no stackshot interference");
639 }
640 }
641 }
642
643 struct instval *latency = cirq_push(&cur_cpu->fire_latencies);
644 latency->iv_instant_ns = cur_ns;
645 latency->iv_val = timer_latency_ns;
646
647 // Snapshot this timer fire's interrupt latency, so the next one
648 // can make an adjustment to the period.
649 last_fire_latency_ns = timer_latency_ns;
650 }
651 last_fire_ns = cur_ns;
652 last_fire_cpuid = tp->cpuid;
653
654 if (nfires >= FIRES_THRESHOLD) {
655 ktrace_end(s, 1);
656 }
657 });
658
659 configure_kperf_timer_samplers(TIMER_PERIOD_NS, KPERF_SAMPLER_TINFO);
660
661 ktrace_set_completion_handler(s, ^{
662 double duration_secs = (double)(last_fire_ns - first_fire_ns) /
663 NSEC_PER_SEC;
664 T_LOG("stopping trace after %.2f seconds", duration_secs);
665
666 T_PASS("saw %" PRIu64 " timer fires (%g fires/second) without "
667 "oversampling", nfires, (double)nfires / (double)duration_secs);
668
669 T_END;
670 });
671
672 start_tracing_with_timeout(s, 5);
673
674 // Get all CPUs out of idle.
675 uint64_t *counts = kpc_counterbuf_alloc();
676 (void)kpc_get_cpu_counters(true,KPC_CLASS_CONFIGURABLE_MASK, NULL, counts);
677 free(counts);
678
679 dispatch_main();
680 }
681
682 T_DECL(kperf_timer_stress, "repeatedly enable and disable timers")
683 {
684 start_controlling_ktrace();
685
686 const int niters = 500;
687 for (int i = 0; i < niters; i++) {
688 configure_kperf_stacks_timer(-1, 1, true);
689 T_QUIET;
690 T_ASSERT_POSIX_SUCCESS(kperf_sample_set(1), "start kperf sampling");
691 usleep(2000);
692 kperf_reset();
693 }
694 T_LOG("configured kperf with a timer %d times", niters);
695 }
696
697 #pragma mark - kdebug triggers
698
699 #define KDEBUG_TRIGGER_TIMEOUT_NS (10 * NSEC_PER_SEC)
700
701 #define NON_TRIGGER_CLASS UINT32_C(0xfd)
702 #define NON_TRIGGER_SUBCLASS UINT32_C(0xff)
703 #define NON_TRIGGER_CODE UINT32_C(0xff)
704
705 #define NON_TRIGGER_EVENT \
706 (KDBG_EVENTID(NON_TRIGGER_CLASS, NON_TRIGGER_SUBCLASS, \
707 NON_TRIGGER_CODE))
708
709 static void
expect_kdebug_trigger(const char * filter_desc,const uint32_t * debugids,unsigned int n_debugids)710 expect_kdebug_trigger(const char *filter_desc, const uint32_t *debugids,
711 unsigned int n_debugids)
712 {
713 __block int missing_kernel_stacks = 0;
714 __block int missing_user_stacks = 0;
715 ktrace_session_t s;
716 kperf_kdebug_filter_t filter;
717
718 s = ktrace_session_create();
719 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(s, "ktrace_session_create");
720 ktrace_set_collection_interval(s, 100);
721
722 ktrace_events_single(s, PERF_STK_KHDR, ^(struct trace_point *tp) {
723 missing_kernel_stacks--;
724 T_LOG("saw kernel stack with %" PRIu64 " frames, flags = %#"
725 PRIx64, tp->arg2, tp->arg1);
726 });
727 ktrace_events_single(s, PERF_STK_UHDR, ^(struct trace_point *tp) {
728 missing_user_stacks--;
729 T_LOG("saw user stack with %" PRIu64 " frames, flags = %#"
730 PRIx64, tp->arg2, tp->arg1);
731 });
732
733 for (unsigned int i = 0; i < n_debugids; i++) {
734 ktrace_events_single(s, debugids[i], ^(struct trace_point *tp) {
735 missing_kernel_stacks++;
736 missing_user_stacks++;
737 T_LOG("saw event with debugid 0x%" PRIx32, tp->debugid);
738 });
739 }
740
741 ktrace_events_single(s, NON_TRIGGER_EVENT,
742 ^(__unused struct trace_point *tp)
743 {
744 ktrace_end(s, 0);
745 });
746
747 ktrace_set_completion_handler(s, ^{
748 T_EXPECT_LE(missing_kernel_stacks, 0, NULL);
749 T_EXPECT_LE(missing_user_stacks, 0, NULL);
750
751 ktrace_session_destroy(s);
752 T_END;
753 });
754
755 kperf_reset();
756
757 (void)kperf_action_count_set(1);
758 T_ASSERT_POSIX_SUCCESS(kperf_action_samplers_set(1,
759 KPERF_SAMPLER_KSTACK | KPERF_SAMPLER_USTACK), NULL);
760
761 filter = kperf_kdebug_filter_create();
762 T_ASSERT_NOTNULL(filter, NULL);
763
764 T_ASSERT_POSIX_SUCCESS(kperf_kdebug_action_set(1), NULL);
765 T_ASSERT_POSIX_SUCCESS(kperf_kdebug_filter_add_desc(filter, filter_desc),
766 NULL);
767 T_ASSERT_POSIX_SUCCESS(kperf_kdebug_filter_set(filter), NULL);
768 kperf_kdebug_filter_destroy(filter);
769
770 T_ASSERT_POSIX_SUCCESS(kperf_sample_set(1), NULL);
771
772 T_ASSERT_POSIX_ZERO(ktrace_start(s, dispatch_get_main_queue()), NULL);
773
774 // Trace the triggering events.
775
776 for (unsigned int i = 0; i < n_debugids; i++) {
777 T_ASSERT_POSIX_SUCCESS(kdebug_trace(debugids[i], 0, 0, 0, 0), NULL);
778 }
779
780 T_ASSERT_POSIX_SUCCESS(kdebug_trace(NON_TRIGGER_EVENT, 0, 0, 0, 0), NULL);
781
782 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, KDEBUG_TRIGGER_TIMEOUT_NS),
783 dispatch_get_main_queue(), ^(void)
784 {
785 ktrace_end(s, 1);
786 });
787 }
788
789 #define TRIGGER_CLASS UINT32_C(0xfe)
790 #define TRIGGER_CLASS_END UINT32_C(0xfd)
791 #define TRIGGER_SUBCLASS UINT32_C(0xff)
792 #define TRIGGER_CODE UINT32_C(0)
793 #define TRIGGER_DEBUGID \
794 (KDBG_EVENTID(TRIGGER_CLASS, TRIGGER_SUBCLASS, TRIGGER_CODE))
795
796 T_DECL(kperf_kdebug_trigger_classes,
797 "test that kdebug trigger samples on classes")
798 {
799 start_controlling_ktrace();
800
801 const uint32_t class_debugids[] = {
802 KDBG_EVENTID(TRIGGER_CLASS, 1, 1),
803 KDBG_EVENTID(TRIGGER_CLASS, 2, 1),
804 KDBG_EVENTID(TRIGGER_CLASS_END, 1, 1) | DBG_FUNC_END,
805 KDBG_EVENTID(TRIGGER_CLASS_END, 2, 1) | DBG_FUNC_END,
806 };
807
808 expect_kdebug_trigger("C0xfe,C0xfdr", class_debugids,
809 sizeof(class_debugids) / sizeof(class_debugids[0]));
810 dispatch_main();
811 }
812
813 T_DECL(kperf_kdebug_trigger_subclasses,
814 "test that kdebug trigger samples on subclasses")
815 {
816 start_controlling_ktrace();
817
818 const uint32_t subclass_debugids[] = {
819 KDBG_EVENTID(TRIGGER_CLASS, TRIGGER_SUBCLASS, 0),
820 KDBG_EVENTID(TRIGGER_CLASS, TRIGGER_SUBCLASS, 1),
821 KDBG_EVENTID(TRIGGER_CLASS_END, TRIGGER_SUBCLASS, 0) | DBG_FUNC_END,
822 KDBG_EVENTID(TRIGGER_CLASS_END, TRIGGER_SUBCLASS, 1) | DBG_FUNC_END
823 };
824
825 expect_kdebug_trigger("S0xfeff,S0xfdffr", subclass_debugids,
826 sizeof(subclass_debugids) / sizeof(subclass_debugids[0]));
827 dispatch_main();
828 }
829
830 T_DECL(kperf_kdebug_trigger_debugids,
831 "test that kdebug trigger samples on debugids")
832 {
833 start_controlling_ktrace();
834
835 const uint32_t debugids[] = {
836 TRIGGER_DEBUGID
837 };
838
839 expect_kdebug_trigger("D0xfeff0000", debugids,
840 sizeof(debugids) / sizeof(debugids[0]));
841 dispatch_main();
842 }
843
844 // TODO Set a single function specifier filter, expect not to trigger of all
845 // events from that class.
846
847 static void
reset_kperf(void)848 reset_kperf(void)
849 {
850 (void)kperf_reset();
851 (void)sysctlbyname("kperf.debug_level", NULL, NULL, &(int){ 0 },
852 sizeof(int));
853 }
854
855 T_DECL(kperf_kdbg_callstacks,
856 "test that the kdbg_callstacks samples on syscalls")
857 {
858 start_controlling_ktrace();
859
860 ktrace_session_t s;
861 __block bool saw_user_stack = false;
862
863 s = ktrace_session_create();
864 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(s, "ktrace_session_create");
865 ktrace_set_collection_interval(s, 100);
866
867 // Make sure BSD events are traced in order to trigger samples on syscalls.
868 ktrace_events_class(s, DBG_BSD, ^void (__unused struct trace_point *tp) {});
869
870 ktrace_events_single(s, PERF_STK_UHDR, ^(__unused struct trace_point *tp) {
871 saw_user_stack = true;
872 ktrace_end(s, 1);
873 });
874
875 ktrace_set_completion_handler(s, ^{
876 ktrace_session_destroy(s);
877
878 T_EXPECT_TRUE(saw_user_stack,
879 "saw user stack after configuring kdbg_callstacks");
880 T_END;
881 });
882
883 #pragma clang diagnostic push
884 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
885 T_ASSERT_POSIX_SUCCESS(kperf_kdbg_callstacks_set(1), NULL);
886 #pragma clang diagnostic pop
887 T_ATEND(reset_kperf);
888
889 T_ASSERT_POSIX_ZERO(ktrace_start(s, dispatch_get_main_queue()), NULL);
890
891 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 10 * NSEC_PER_SEC),
892 dispatch_get_main_queue(), ^(void) {
893 ktrace_end(s, 1);
894 });
895
896 dispatch_main();
897 }
898
899 #pragma mark - PET
900
901 #define STACKS_WAIT_DURATION_NS (3 * NSEC_PER_SEC)
902
903 static void
904 expect_stacks_traced(void (^setup)(ktrace_session_t s), void (^complete)(void))
905 {
906 ktrace_session_t s;
907
908 s = ktrace_session_create();
909 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(s, "ktrace_session_create");
910 ktrace_set_collection_interval(s, 100);
911 if (setup) {
912 setup(s);
913 }
914
915 __block unsigned int user_stacks = 0;
916 __block unsigned int kernel_stacks = 0;
917
918 ktrace_events_single(s, PERF_STK_UHDR, ^(__unused struct trace_point *tp) {
919 user_stacks++;
920 });
921 ktrace_events_single(s, PERF_STK_KHDR, ^(__unused struct trace_point *tp) {
922 kernel_stacks++;
923 });
924
925 ktrace_set_completion_handler(s, ^(void) {
926 ktrace_session_destroy(s);
927 T_EXPECT_GT(user_stacks, 0U, NULL);
928 T_EXPECT_GT(kernel_stacks, 0U, NULL);
929 complete();
930 });
931
932 T_QUIET; T_ASSERT_POSIX_SUCCESS(kperf_sample_set(1), NULL);
933
934 T_ASSERT_POSIX_ZERO(ktrace_start(s, dispatch_get_main_queue()), NULL);
935
936 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, STACKS_WAIT_DURATION_NS),
937 dispatch_get_main_queue(), ^(void)
938 {
939 kperf_reset();
940 ktrace_end(s, 0);
941 });
942 }
943
944 T_DECL(kperf_pet, "test that PET mode samples kernel and user stacks")
945 {
946 start_controlling_ktrace();
947
948 configure_kperf_stacks_timer(-1, 10, false);
949 T_ASSERT_POSIX_SUCCESS(kperf_timer_pet_set(0), NULL);
950
951 expect_stacks_traced(NULL, ^(void) {
952 T_END;
953 });
954
955 dispatch_main();
956 }
957
958 T_DECL(kperf_lightweight_pet,
959 "test that lightweight PET mode samples kernel and user stacks",
960 T_META_ASROOT(true))
961 {
962 start_controlling_ktrace();
963
964 int set = 1;
965
966 configure_kperf_stacks_timer(-1, 10, false);
967 T_ASSERT_POSIX_SUCCESS(sysctlbyname("kperf.lightweight_pet", NULL, NULL,
968 &set, sizeof(set)), NULL);
969 T_ASSERT_POSIX_SUCCESS(kperf_timer_pet_set(0), NULL);
970
971 __block uint64_t nfires = 0;
972
973 expect_stacks_traced(^(ktrace_session_t s) {
974 ktrace_events_single(s, PERF_TMR_FIRE, ^(struct trace_point *tp) {
975 nfires++;
976 T_QUIET;
977 T_ASSERT_EQ(tp->arg1, (uint64_t)0,
978 "timer fire should have timer ID of 0");
979 T_QUIET;
980 T_ASSERT_EQ(tp->arg2, (uint64_t)1,
981 "timer fire should have PET bit set");
982 });
983 }, ^(void) {
984 T_ASSERT_GT(nfires, (uint64_t)0, "timer fired at least once");
985 T_END;
986 });
987
988 dispatch_main();
989 }
990
991 T_DECL(kperf_pet_stress, "repeatedly enable and disable PET mode")
992 {
993 start_controlling_ktrace();
994
995 const int niters = 500;
996 for (int i = 0; i < niters; i++) {
997 configure_kperf_stacks_timer(-1, 1, true);
998 T_QUIET; T_ASSERT_POSIX_SUCCESS(kperf_timer_pet_set(0), NULL);
999 T_QUIET;
1000 T_ASSERT_POSIX_SUCCESS(kperf_sample_set(1), "start kperf sampling");
1001 usleep(2000);
1002 kperf_reset();
1003 }
1004
1005 T_PASS("configured kperf PET %d times", niters);
1006 }
1007
1008 #pragma mark - PMCs
1009
1010 T_DECL(kperf_pmc_config_only,
1011 "shouldn't show PMC config events unless requested")
1012 {
1013 start_controlling_ktrace();
1014
1015 __block bool saw_kpc_config = false;
1016 __block bool saw_kpc_reg = false;
1017
1018 ktrace_session_t s = ktrace_session_create();
1019 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(s, "ktrace_session_create");
1020 ktrace_set_collection_interval(s, 100);
1021
1022 ktrace_events_single(s, PERF_KPC_CONFIG,
1023 ^(__unused struct trace_point *tp) {
1024 saw_kpc_config = true;
1025 });
1026 ktrace_events_single(s, PERF_KPC_REG,
1027 ^(__unused struct trace_point *tp) {
1028 saw_kpc_reg = true;
1029 });
1030 ktrace_events_single(s, PERF_KPC_REG32,
1031 ^(__unused struct trace_point *tp) {
1032 saw_kpc_reg = true;
1033 });
1034
1035 ktrace_set_completion_handler(s, ^{
1036 ktrace_session_destroy(s);
1037 T_EXPECT_FALSE(saw_kpc_config,
1038 "should see no KPC configs without sampler enabled");
1039 T_EXPECT_FALSE(saw_kpc_reg,
1040 "should see no KPC registers without sampler enabled");
1041 T_END;
1042 });
1043
1044 uint32_t nconfigs = kpc_get_config_count(KPC_CLASS_CONFIGURABLE_MASK);
1045 uint64_t *config = calloc(nconfigs, sizeof(*config));
1046 config[0] = 0x02;
1047 int ret = kpc_set_config(KPC_CLASS_CONFIGURABLE_MASK, config);
1048 T_ASSERT_POSIX_SUCCESS(ret, "configured kpc");
1049 T_QUIET;
1050 T_ASSERT_POSIX_SUCCESS(kpc_set_counting(KPC_CLASS_CONFIGURABLE_MASK),
1051 "kpc_set_counting");
1052
1053 (void)kperf_action_count_set(1);
1054 T_ATEND(reset_kperf);
1055 T_QUIET;
1056 T_ASSERT_POSIX_SUCCESS(kperf_action_samplers_set(1, KPERF_SAMPLER_PMC_CPU),
1057 NULL);
1058
1059 (void)kperf_timer_count_set(1);
1060 T_QUIET;
1061 T_ASSERT_POSIX_SUCCESS(kperf_timer_period_set(0,
1062 kperf_ns_to_ticks(TIMER_PERIOD_NS)), NULL);
1063 T_QUIET;
1064 T_ASSERT_POSIX_SUCCESS(kperf_timer_action_set(0, 1), NULL);
1065
1066 T_ASSERT_POSIX_SUCCESS(kperf_sample_set(1), "start kperf sampling");
1067
1068 T_ASSERT_POSIX_ZERO(ktrace_start(s, dispatch_get_main_queue()), NULL);
1069
1070 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 10 * NSEC_PER_SEC),
1071 dispatch_get_main_queue(), ^(void) {
1072 ktrace_end(s, 1);
1073 });
1074
1075 dispatch_main();
1076 }
1077
1078 static void
skip_if_monotonic_unsupported(void)1079 skip_if_monotonic_unsupported(void)
1080 {
1081 int r;
1082 int supported = 0;
1083 size_t supported_size = sizeof(supported);
1084
1085 r = sysctlbyname("kern.monotonic.supported", &supported, &supported_size,
1086 NULL, 0);
1087 if (r < 0) {
1088 T_WITH_ERRNO;
1089 T_SKIP("could not find \"kern.monotonic.supported\" sysctl");
1090 }
1091
1092 if (!supported) {
1093 T_SKIP("monotonic is not supported on this platform");
1094 }
1095 }
1096
1097 #define INSTRS_CYCLES_UPPER 500
1098 #define INSTRS_CYCLES_LOWER 50
1099
1100 T_DECL(kperf_sample_instrs_cycles,
1101 "ensure instructions and cycles are sampled")
1102 {
1103 T_SETUPBEGIN;
1104
1105 skip_if_monotonic_unsupported();
1106 start_controlling_ktrace();
1107
1108 ktrace_session_t sess = ktrace_session_create();
1109 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(sess, "ktrace_session_create");
1110 ktrace_set_collection_interval(sess, 100);
1111
1112 __block uint64_t ninstrs_cycles = 0;
1113 __block uint64_t nzeroes = 0;
1114 ktrace_events_single(sess, PERF_INSTR_DATA,
1115 ^(__unused struct trace_point *tp) {
1116 ninstrs_cycles++;
1117 if (tp->arg1 == 0) {
1118 T_LOG("%llx (%s)\n", tp->threadid, tp->command);
1119 nzeroes++;
1120 }
1121 if (ninstrs_cycles >= INSTRS_CYCLES_UPPER) {
1122 ktrace_end(sess, 1);
1123 }
1124 });
1125
1126 ktrace_set_collection_interval(sess, 200);
1127
1128 ktrace_set_completion_handler(sess, ^{
1129 T_EXPECT_GE(ninstrs_cycles, (uint64_t)INSTRS_CYCLES_LOWER,
1130 "saw enough instructions and cycles events");
1131 T_EXPECT_EQ(nzeroes, UINT64_C(0),
1132 "saw no events with 0 instructions");
1133 T_END;
1134 });
1135
1136 (void)kperf_action_count_set(1);
1137 T_ATEND(reset_kperf);
1138 T_QUIET;
1139 T_ASSERT_POSIX_SUCCESS(kperf_action_samplers_set(1,
1140 KPERF_SAMPLER_TH_INSTRS_CYCLES), NULL);
1141
1142 (void)kperf_timer_count_set(1);
1143 T_QUIET;
1144 T_ASSERT_POSIX_SUCCESS(kperf_timer_period_set(0,
1145 kperf_ns_to_ticks(TIMER_PERIOD_NS)), NULL);
1146 T_QUIET;
1147 T_ASSERT_POSIX_SUCCESS(kperf_timer_action_set(0, 1), NULL);
1148
1149 T_ASSERT_POSIX_SUCCESS(kperf_sample_set(1), "start kperf sampling");
1150
1151 T_ASSERT_POSIX_ZERO(ktrace_start(sess, dispatch_get_main_queue()),
1152 NULL);
1153
1154 T_SETUPEND;
1155
1156 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 10 * NSEC_PER_SEC),
1157 dispatch_get_main_queue(), ^(void) {
1158 ktrace_end(sess, 1);
1159 });
1160
1161 dispatch_main();
1162 }
1163
1164 #define UNCOMMON_EVENTID 0xfeedfac0
1165 #define LABEL "this_is_a_test_label_that_is_very_long_and_will_be_truncated" \
1166 "_but_needs_some_more_length_for_good_measure"
1167 #define MAX_LABEL_LEN 64
1168 static_assert(sizeof(LABEL) > MAX_LABEL_LEN,
1169 "should be larger than the max length of a label");
1170
1171 T_DECL(kperf_dispatch_labels, "ensure dispatch queue labels are sampled")
1172 {
1173 T_SETUPBEGIN;
1174 start_controlling_ktrace();
1175 ktrace_session_t sess = ktrace_session_create();
1176 ktrace_set_collection_interval(sess, 200);
1177
1178 /*
1179 * Expect to see the label that was sampled by kperf.
1180 */
1181 __block uint64_t nlabels = 0;
1182 char obs_label[MAX_LABEL_LEN + 1] = {};
1183 char *obs_label_b = obs_label;
1184 char exp_label[MAX_LABEL_LEN + 1] = {};
1185 strlcpy(exp_label, LABEL, sizeof(exp_label));
1186 char *exp_label_b = exp_label;
1187
1188 ktrace_events_single(sess, PERF_DISPLABEL, ^(struct trace_point *tp) {
1189 nlabels++;
1190 size_t argsize = ktrace_is_kernel_64_bit(sess) ? 8 : 4;
1191 strncat(obs_label_b, (char *)&tp->arg1, argsize);
1192 strncat(obs_label_b, (char *)&tp->arg2, argsize);
1193 strncat(obs_label_b, (char *)&tp->arg3, argsize);
1194 strncat(obs_label_b, (char *)&tp->arg4, argsize);
1195 if (tp->debugid & DBG_FUNC_END) {
1196 ktrace_end(sess, 1);
1197 }
1198 });
1199 ktrace_events_single(sess, PERF_DISPSAMPLE, ^(struct trace_point *tp) {
1200 if (tp->debugid & DBG_FUNC_END) {
1201 T_LOG("ending sample event returned %d (%s)",
1202 (int)tp->arg1, strerror((int)tp->arg1));
1203 }
1204 });
1205 ktrace_events_single(sess, UNCOMMON_EVENTID,
1206 ^(__unused struct trace_point *tp) {
1207 T_LOG("saw triggering event");
1208 });
1209 ktrace_set_completion_handler(sess, ^{
1210 T_EXPECT_GT(nlabels, 0ULL, "saw %" PRIu64
1211 " dispatch queue label events", nlabels);
1212 T_EXPECT_EQ_STR(obs_label_b, exp_label_b, "label string is correct");
1213 T_END;
1214 });
1215
1216 /*
1217 * Set up kperf to log a dispatch queue label when an uncommon event ID
1218 * is traced.
1219 */
1220 (void)sysctlbyname("kperf.debug_level", NULL, NULL, &(int){ 2 }, sizeof(int));
1221 (void)kperf_action_count_set(1);
1222 T_ATEND(reset_kperf);
1223 T_QUIET;
1224 T_ASSERT_POSIX_SUCCESS(kperf_action_samplers_set(1,
1225 KPERF_SAMPLER_TH_DISPATCH), NULL);
1226 (void)kperf_kdebug_action_set(1);
1227 kperf_kdebug_filter_t kdfilt = kperf_kdebug_filter_create();
1228 T_QUIET;
1229 T_ASSERT_NOTNULL(kdfilt, "create kdebug filter for kperf");
1230 T_QUIET;
1231 T_ASSERT_POSIX_SUCCESS(
1232 kperf_kdebug_filter_add_debugid(kdfilt, UNCOMMON_EVENTID),
1233 "add debugid to filter on");
1234 T_QUIET;
1235 T_ASSERT_POSIX_SUCCESS(
1236 kperf_kdebug_filter_set(kdfilt), "set filter for kperf");
1237 T_ASSERT_POSIX_SUCCESS(kperf_sample_set(1), "start kperf sampling");
1238
1239 T_ASSERT_POSIX_ZERO(ktrace_start(sess, dispatch_get_main_queue()),
1240 NULL);
1241
1242 /*
1243 * Create the queue and emit the sampling event from it.
1244 */
1245 dispatch_queue_t testq = dispatch_queue_create(LABEL, 0);
1246 T_ASSERT_NOTNULL(testq, "created queue with label: " LABEL);
1247 dispatch_async(testq, ^{
1248 kdebug_trace(UNCOMMON_EVENTID, 0, 0, 0, 0);
1249 sleep(10);
1250 });
1251
1252 T_SETUPEND;
1253
1254 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 5 * NSEC_PER_SEC),
1255 dispatch_get_main_queue(), ^(void) {
1256 ktrace_end(sess, 1);
1257 });
1258
1259 dispatch_main();
1260 }
1261
1262 T_HELPER_DECL(kperf_blessed_helper,
1263 "drop priviliges and attempt to configure kperf")
1264 {
1265 drop_priv();
1266 (void)kperf_action_count_set(1);
1267 errno = 0;
1268 int ret = kperf_lazy_wait_action_set(1);
1269 int error = errno;
1270 exit(ret != 0 ? (error == 0) ? EINVAL : error : 0);
1271 }
1272
1273 static pid_t
spawn_bless_helper(void)1274 spawn_bless_helper(void)
1275 {
1276 char test_path[MAXPATHLEN] = { 0 };
1277 int ret = proc_pidpath(getpid(), test_path, MAXPATHLEN);
1278 T_QUIET; T_ASSERT_POSIX_SUCCESS(ret, "query path for current process");
1279 T_LOG("spawning helper tool at %s", test_path);
1280 char *child_argv[] = { test_path, "-n", "kperf_blessed_helper", NULL };
1281 pid_t child_pid = -1;
1282 int error = dt_launch_tool(&child_pid, child_argv, true, NULL, NULL);
1283 T_ASSERT_POSIX_ZERO(error, "spawned child with pid %d", child_pid);
1284 T_QUIET; T_ASSERT_GT(child_pid, 0, "child pid is valid");
1285 return child_pid;
1286 }
1287
1288 static int
test_child_process(pid_t child_pid)1289 test_child_process(pid_t child_pid)
1290 {
1291 int ret = kill(child_pid, SIGCONT);
1292 T_ASSERT_POSIX_SUCCESS(ret, "continuing child process");
1293 int status = 0;
1294 ret = waitpid(child_pid, &status, 0);
1295 T_ASSERT_POSIX_SUCCESS(ret, "waited on child process");
1296 return status;
1297 }
1298
1299 T_DECL(kperf_unblessed_refusal,
1300 "check that an unblessed child cannot access ktrace")
1301 {
1302 T_SETUPBEGIN;
1303 pid_t child_pid = spawn_bless_helper();
1304 T_SETUPEND;
1305 int status = test_child_process(child_pid);
1306 int exit_status = WEXITSTATUS(status);
1307 T_EXPECT_NE(exit_status, 0, "child failed to access ktrace with %d (%s)",
1308 exit_status, exit_status == 0 ? "ok" : strerror(exit_status));
1309 }
1310
1311 T_DECL(kperf_blessed_ownership, "check that a blessed child can access ktrace")
1312 {
1313 T_LOG("parent pid is %d\n", getpid());
1314 T_SETUPBEGIN;
1315 pid_t child_pid = spawn_bless_helper();
1316 T_SETUPEND;
1317 int ret = kperf_bless_set(child_pid);
1318 T_ASSERT_POSIX_SUCCESS(ret, "blessed child with pid %d", child_pid);
1319 int status = test_child_process(child_pid);
1320 int exit_status = WEXITSTATUS(status);
1321 T_EXPECT_EQ(exit_status, 0, "child status was %d (%s)", exit_status,
1322 exit_status == 0 ? "ok" : strerror(exit_status));
1323 ret = kperf_bless_set(-1);
1324 T_ASSERT_POSIX_SUCCESS(ret, "removed blessing from child");
1325 }
1326