2 * Read-Copy Update module-based performance-test facility
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
18 * Copyright (C) IBM Corporation, 2015
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/init.h>
25 #include <linux/module.h>
26 #include <linux/kthread.h>
27 #include <linux/err.h>
28 #include <linux/spinlock.h>
29 #include <linux/smp.h>
30 #include <linux/rcupdate.h>
31 #include <linux/interrupt.h>
32 #include <linux/sched.h>
33 #include <linux/atomic.h>
34 #include <linux/bitops.h>
35 #include <linux/completion.h>
36 #include <linux/moduleparam.h>
37 #include <linux/percpu.h>
38 #include <linux/notifier.h>
39 #include <linux/reboot.h>
40 #include <linux/freezer.h>
41 #include <linux/cpu.h>
42 #include <linux/delay.h>
43 #include <linux/stat.h>
44 #include <linux/srcu.h>
45 #include <linux/slab.h>
46 #include <asm/byteorder.h>
47 #include <linux/torture.h>
48 #include <linux/vmalloc.h>
50 MODULE_LICENSE("GPL");
51 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.vnet.ibm.com>");
53 #define PERF_FLAG "-perf:"
54 #define PERFOUT_STRING(s) \
55 pr_alert("%s" PERF_FLAG s "\n", perf_type)
56 #define VERBOSE_PERFOUT_STRING(s) \
57 do { if (verbose) pr_alert("%s" PERF_FLAG " %s\n", perf_type, s); } while (0)
58 #define VERBOSE_PERFOUT_ERRSTRING(s) \
59 do { if (verbose) pr_alert("%s" PERF_FLAG "!!! %s\n", perf_type, s); } while (0)
61 torture_param(bool, gp_exp, true, "Use expedited GP wait primitives");
62 torture_param(int, holdoff, 10, "Holdoff time before test start (s)");
63 torture_param(int, nreaders, -1, "Number of RCU reader threads");
64 torture_param(int, nwriters, -1, "Number of RCU updater threads");
65 torture_param(bool, shutdown, false, "Shutdown at end of performance tests.");
66 torture_param(bool, verbose, true, "Enable verbose debugging printk()s");
68 static char *perf_type = "rcu";
69 module_param(perf_type, charp, 0444);
70 MODULE_PARM_DESC(perf_type, "Type of RCU to performance-test (rcu, rcu_bh, ...)");
72 static int nrealreaders;
73 static int nrealwriters;
74 static struct task_struct **writer_tasks;
75 static struct task_struct **reader_tasks;
76 static struct task_struct *shutdown_task;
78 static u64 **writer_durations;
79 static int *writer_n_durations;
80 static atomic_t n_rcu_perf_reader_started;
81 static atomic_t n_rcu_perf_writer_started;
82 static atomic_t n_rcu_perf_writer_finished;
83 static wait_queue_head_t shutdown_wq;
84 static u64 t_rcu_perf_writer_started;
85 static u64 t_rcu_perf_writer_finished;
86 static unsigned long b_rcu_perf_writer_started;
87 static unsigned long b_rcu_perf_writer_finished;
89 static int rcu_perf_writer_state;
91 #define RTWS_EXP_SYNC 1
94 #define RTWS_STOPPING 3
96 #define MAX_MEAS 10000
99 #if defined(MODULE) || defined(CONFIG_RCU_PERF_TEST_RUNNABLE)
100 #define RCUPERF_RUNNABLE_INIT 1
102 #define RCUPERF_RUNNABLE_INIT 0
104 static int perf_runnable = RCUPERF_RUNNABLE_INIT;
105 module_param(perf_runnable, int, 0444);
106 MODULE_PARM_DESC(perf_runnable, "Start rcuperf at boot");
109 * Operations vector for selecting different types of tests.
112 struct rcu_perf_ops {
115 void (*cleanup)(void);
116 int (*readlock)(void);
117 void (*readunlock)(int idx);
118 unsigned long (*started)(void);
119 unsigned long (*completed)(void);
120 unsigned long (*exp_completed)(void);
122 void (*exp_sync)(void);
126 static struct rcu_perf_ops *cur_ops;
129 * Definitions for rcu perf testing.
132 static int rcu_perf_read_lock(void) __acquires(RCU)
138 static void rcu_perf_read_unlock(int idx) __releases(RCU)
143 static unsigned long __maybe_unused rcu_no_completed(void)
148 static void rcu_sync_perf_init(void)
152 static struct rcu_perf_ops rcu_ops = {
154 .init = rcu_sync_perf_init,
155 .readlock = rcu_perf_read_lock,
156 .readunlock = rcu_perf_read_unlock,
157 .started = rcu_batches_started,
158 .completed = rcu_batches_completed,
159 .exp_completed = rcu_exp_batches_completed,
160 .sync = synchronize_rcu,
161 .exp_sync = synchronize_rcu_expedited,
166 * Definitions for rcu_bh perf testing.
169 static int rcu_bh_perf_read_lock(void) __acquires(RCU_BH)
175 static void rcu_bh_perf_read_unlock(int idx) __releases(RCU_BH)
177 rcu_read_unlock_bh();
180 static struct rcu_perf_ops rcu_bh_ops = {
181 .ptype = RCU_BH_FLAVOR,
182 .init = rcu_sync_perf_init,
183 .readlock = rcu_bh_perf_read_lock,
184 .readunlock = rcu_bh_perf_read_unlock,
185 .started = rcu_batches_started_bh,
186 .completed = rcu_batches_completed_bh,
187 .exp_completed = rcu_exp_batches_completed_sched,
188 .sync = synchronize_rcu_bh,
189 .exp_sync = synchronize_rcu_bh_expedited,
194 * Definitions for srcu perf testing.
197 DEFINE_STATIC_SRCU(srcu_ctl_perf);
198 static struct srcu_struct *srcu_ctlp = &srcu_ctl_perf;
200 static int srcu_perf_read_lock(void) __acquires(srcu_ctlp)
202 return srcu_read_lock(srcu_ctlp);
205 static void srcu_perf_read_unlock(int idx) __releases(srcu_ctlp)
207 srcu_read_unlock(srcu_ctlp, idx);
210 static unsigned long srcu_perf_completed(void)
212 return srcu_batches_completed(srcu_ctlp);
215 static void srcu_perf_synchronize(void)
217 synchronize_srcu(srcu_ctlp);
220 static void srcu_perf_synchronize_expedited(void)
222 synchronize_srcu_expedited(srcu_ctlp);
225 static struct rcu_perf_ops srcu_ops = {
226 .ptype = SRCU_FLAVOR,
227 .init = rcu_sync_perf_init,
228 .readlock = srcu_perf_read_lock,
229 .readunlock = srcu_perf_read_unlock,
231 .completed = srcu_perf_completed,
232 .exp_completed = srcu_perf_completed,
233 .sync = srcu_perf_synchronize,
234 .exp_sync = srcu_perf_synchronize_expedited,
239 * Definitions for sched perf testing.
242 static int sched_perf_read_lock(void)
248 static void sched_perf_read_unlock(int idx)
253 static struct rcu_perf_ops sched_ops = {
254 .ptype = RCU_SCHED_FLAVOR,
255 .init = rcu_sync_perf_init,
256 .readlock = sched_perf_read_lock,
257 .readunlock = sched_perf_read_unlock,
258 .started = rcu_batches_started_sched,
259 .completed = rcu_batches_completed_sched,
260 .exp_completed = rcu_exp_batches_completed_sched,
261 .sync = synchronize_sched,
262 .exp_sync = synchronize_sched_expedited,
266 #ifdef CONFIG_TASKS_RCU
269 * Definitions for RCU-tasks perf testing.
272 static int tasks_perf_read_lock(void)
277 static void tasks_perf_read_unlock(int idx)
281 static struct rcu_perf_ops tasks_ops = {
282 .ptype = RCU_TASKS_FLAVOR,
283 .init = rcu_sync_perf_init,
284 .readlock = tasks_perf_read_lock,
285 .readunlock = tasks_perf_read_unlock,
286 .started = rcu_no_completed,
287 .completed = rcu_no_completed,
288 .sync = synchronize_rcu_tasks,
289 .exp_sync = synchronize_rcu_tasks,
293 #define RCUPERF_TASKS_OPS &tasks_ops,
295 static bool __maybe_unused torturing_tasks(void)
297 return cur_ops == &tasks_ops;
300 #else /* #ifdef CONFIG_TASKS_RCU */
302 #define RCUPERF_TASKS_OPS
304 static bool __maybe_unused torturing_tasks(void)
309 #endif /* #else #ifdef CONFIG_TASKS_RCU */
312 * If performance tests complete, wait for shutdown to commence.
314 static void rcu_perf_wait_shutdown(void)
316 cond_resched_rcu_qs();
317 if (atomic_read(&n_rcu_perf_writer_finished) < nrealwriters)
319 while (!torture_must_stop())
320 schedule_timeout_uninterruptible(1);
324 * RCU perf reader kthread. Repeatedly does empty RCU read-side
325 * critical section, minimizing update-side interference.
328 rcu_perf_reader(void *arg)
334 VERBOSE_PERFOUT_STRING("rcu_perf_reader task started");
335 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
336 set_user_nice(current, MAX_NICE);
337 atomic_inc(&n_rcu_perf_reader_started);
340 local_irq_save(flags);
341 idx = cur_ops->readlock();
342 cur_ops->readunlock(idx);
343 local_irq_restore(flags);
344 rcu_perf_wait_shutdown();
345 } while (!torture_must_stop());
346 torture_kthread_stopping("rcu_perf_reader");
351 * RCU perf writer kthread. Repeatedly does a grace period.
354 rcu_perf_writer(void *arg)
359 struct sched_param sp;
360 bool started = false, done = false, alldone = false;
363 u64 *wdpp = writer_durations[me];
365 VERBOSE_PERFOUT_STRING("rcu_perf_writer task started");
366 WARN_ON(rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp);
367 WARN_ON(rcu_gp_is_normal() && gp_exp);
369 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
370 sp.sched_priority = 1;
371 sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
374 schedule_timeout_uninterruptible(holdoff * HZ);
376 t = ktime_get_mono_fast_ns();
377 if (atomic_inc_return(&n_rcu_perf_writer_started) >= nrealwriters) {
378 t_rcu_perf_writer_started = t;
380 b_rcu_perf_writer_started =
381 cur_ops->exp_completed() / 2;
383 b_rcu_perf_writer_started =
384 cur_ops->completed();
390 *wdp = ktime_get_mono_fast_ns();
392 rcu_perf_writer_state = RTWS_EXP_SYNC;
395 rcu_perf_writer_state = RTWS_SYNC;
398 rcu_perf_writer_state = RTWS_IDLE;
399 t = ktime_get_mono_fast_ns();
403 atomic_read(&n_rcu_perf_writer_started) >= nrealwriters)
405 if (!done && i >= MIN_MEAS) {
407 sp.sched_priority = 0;
408 sched_setscheduler_nocheck(current,
410 pr_alert("%s" PERF_FLAG
411 "rcu_perf_writer %ld has %d measurements\n",
412 perf_type, me, MIN_MEAS);
413 if (atomic_inc_return(&n_rcu_perf_writer_finished) >=
415 schedule_timeout_interruptible(10);
416 rcu_ftrace_dump(DUMP_ALL);
417 PERFOUT_STRING("Test complete");
418 t_rcu_perf_writer_finished = t;
420 b_rcu_perf_writer_finished =
421 cur_ops->exp_completed() / 2;
423 b_rcu_perf_writer_finished =
424 cur_ops->completed();
427 smp_mb(); /* Assign before wake. */
428 wake_up(&shutdown_wq);
432 if (done && !alldone &&
433 atomic_read(&n_rcu_perf_writer_finished) >= nrealwriters)
435 if (started && !alldone && i < MAX_MEAS - 1)
437 rcu_perf_wait_shutdown();
438 } while (!torture_must_stop());
439 rcu_perf_writer_state = RTWS_STOPPING;
440 writer_n_durations[me] = i_max;
441 torture_kthread_stopping("rcu_perf_writer");
446 rcu_perf_print_module_parms(struct rcu_perf_ops *cur_ops, const char *tag)
448 pr_alert("%s" PERF_FLAG
449 "--- %s: nreaders=%d nwriters=%d verbose=%d shutdown=%d\n",
450 perf_type, tag, nrealreaders, nrealwriters, verbose, shutdown);
454 rcu_perf_cleanup(void)
462 if (torture_cleanup_begin())
466 for (i = 0; i < nrealreaders; i++)
467 torture_stop_kthread(rcu_perf_reader,
473 for (i = 0; i < nrealwriters; i++) {
474 torture_stop_kthread(rcu_perf_writer,
476 if (!writer_n_durations)
478 j = writer_n_durations[i];
479 pr_alert("%s%s writer %d gps: %d\n",
480 perf_type, PERF_FLAG, i, j);
483 pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n",
484 perf_type, PERF_FLAG,
485 t_rcu_perf_writer_started, t_rcu_perf_writer_finished,
486 t_rcu_perf_writer_finished -
487 t_rcu_perf_writer_started,
489 b_rcu_perf_writer_finished -
490 b_rcu_perf_writer_started);
491 for (i = 0; i < nrealwriters; i++) {
492 if (!writer_durations)
494 if (!writer_n_durations)
496 wdpp = writer_durations[i];
499 for (j = 0; j <= writer_n_durations[i]; j++) {
501 pr_alert("%s%s %4d writer-duration: %5d %llu\n",
502 perf_type, PERF_FLAG,
505 schedule_timeout_uninterruptible(1);
507 kfree(writer_durations[i]);
510 kfree(writer_durations);
511 kfree(writer_n_durations);
514 /* Do flavor-specific cleanup operations. */
515 if (cur_ops->cleanup != NULL)
518 torture_cleanup_end();
522 * Return the number if non-negative. If -1, the number of CPUs.
523 * If less than -1, that much less than the number of CPUs, but
526 static int compute_real(int n)
533 nr = num_online_cpus() + 1 + n;
541 * RCU perf shutdown kthread. Just waits to be awakened, then shuts
545 rcu_perf_shutdown(void *arg)
548 wait_event(shutdown_wq,
549 atomic_read(&n_rcu_perf_writer_finished) >=
551 } while (atomic_read(&n_rcu_perf_writer_finished) < nrealwriters);
552 smp_mb(); /* Wake before output. */
563 static struct rcu_perf_ops *perf_ops[] = {
564 &rcu_ops, &rcu_bh_ops, &srcu_ops, &sched_ops,
568 if (!torture_init_begin(perf_type, verbose, &perf_runnable))
571 /* Process args and tell the world that the perf'er is on the job. */
572 for (i = 0; i < ARRAY_SIZE(perf_ops); i++) {
573 cur_ops = perf_ops[i];
574 if (strcmp(perf_type, cur_ops->name) == 0)
577 if (i == ARRAY_SIZE(perf_ops)) {
578 pr_alert("rcu-perf: invalid perf type: \"%s\"\n",
580 pr_alert("rcu-perf types:");
581 for (i = 0; i < ARRAY_SIZE(perf_ops); i++)
582 pr_alert(" %s", perf_ops[i]->name);
590 nrealwriters = compute_real(nwriters);
591 nrealreaders = compute_real(nreaders);
592 atomic_set(&n_rcu_perf_reader_started, 0);
593 atomic_set(&n_rcu_perf_writer_started, 0);
594 atomic_set(&n_rcu_perf_writer_finished, 0);
595 rcu_perf_print_module_parms(cur_ops, "Start of test");
597 /* Start up the kthreads. */
600 init_waitqueue_head(&shutdown_wq);
601 firsterr = torture_create_kthread(rcu_perf_shutdown, NULL,
605 schedule_timeout_uninterruptible(1);
607 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
609 if (reader_tasks == NULL) {
610 VERBOSE_PERFOUT_ERRSTRING("out of memory");
614 for (i = 0; i < nrealreaders; i++) {
615 firsterr = torture_create_kthread(rcu_perf_reader, (void *)i,
620 while (atomic_read(&n_rcu_perf_reader_started) < nrealreaders)
621 schedule_timeout_uninterruptible(1);
622 writer_tasks = kcalloc(nrealwriters, sizeof(reader_tasks[0]),
624 writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations),
627 kcalloc(nrealwriters, sizeof(*writer_n_durations),
629 if (!writer_tasks || !writer_durations || !writer_n_durations) {
630 VERBOSE_PERFOUT_ERRSTRING("out of memory");
634 for (i = 0; i < nrealwriters; i++) {
635 writer_durations[i] =
636 kcalloc(MAX_MEAS, sizeof(*writer_durations[i]),
638 if (!writer_durations[i])
640 firsterr = torture_create_kthread(rcu_perf_writer, (void *)i,
654 module_init(rcu_perf_init);
655 module_exit(rcu_perf_cleanup);