1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Benchmark synthesis of perf events such as at the start of a 'perf
4 * record'. Synthesis is done on the current process and the 'dummy' event
5 * handlers are invoked that support dump_trace but otherwise do nothing.
6 *
7 * Copyright 2019 Google LLC.
8 */
9 #include <stdio.h>
10 #include "bench.h"
11 #include "../util/debug.h"
12 #include "../util/session.h"
13 #include "../util/stat.h"
14 #include "../util/synthetic-events.h"
15 #include "../util/target.h"
16 #include "../util/thread_map.h"
17 #include "../util/tool.h"
18 #include "../util/util.h"
19 #include <linux/atomic.h>
20 #include <linux/err.h>
21 #include <linux/time64.h>
22 #include <subcmd/parse-options.h>
23
24 static unsigned int min_threads = 1;
25 static unsigned int max_threads = UINT_MAX;
26 static unsigned int single_iterations = 10000;
27 static unsigned int multi_iterations = 10;
28 static bool run_st;
29 static bool run_mt;
30
31 static const struct option options[] = {
32 OPT_BOOLEAN('s', "st", &run_st, "Run single threaded benchmark"),
33 OPT_BOOLEAN('t', "mt", &run_mt, "Run multi-threaded benchmark"),
34 OPT_UINTEGER('m', "min-threads", &min_threads,
35 "Minimum number of threads in multithreaded bench"),
36 OPT_UINTEGER('M', "max-threads", &max_threads,
37 "Maximum number of threads in multithreaded bench"),
38 OPT_UINTEGER('i', "single-iterations", &single_iterations,
39 "Number of iterations used to compute single-threaded average"),
40 OPT_UINTEGER('I', "multi-iterations", &multi_iterations,
41 "Number of iterations used to compute multi-threaded average"),
42 OPT_END()
43 };
44
45 static const char *const bench_usage[] = {
46 "perf bench internals synthesize <options>",
47 NULL
48 };
49
50 static atomic_t event_count;
51
process_synthesized_event(struct perf_tool * tool __maybe_unused,union perf_event * event __maybe_unused,struct perf_sample * sample __maybe_unused,struct machine * machine __maybe_unused)52 static int process_synthesized_event(struct perf_tool *tool __maybe_unused,
53 union perf_event *event __maybe_unused,
54 struct perf_sample *sample __maybe_unused,
55 struct machine *machine __maybe_unused)
56 {
57 atomic_inc(&event_count);
58 return 0;
59 }
60
do_run_single_threaded(struct perf_session * session,struct perf_thread_map * threads,struct target * target,bool data_mmap)61 static int do_run_single_threaded(struct perf_session *session,
62 struct perf_thread_map *threads,
63 struct target *target, bool data_mmap)
64 {
65 const unsigned int nr_threads_synthesize = 1;
66 struct timeval start, end, diff;
67 u64 runtime_us;
68 unsigned int i;
69 double time_average, time_stddev, event_average, event_stddev;
70 int err;
71 struct stats time_stats, event_stats;
72
73 init_stats(&time_stats);
74 init_stats(&event_stats);
75
76 for (i = 0; i < single_iterations; i++) {
77 atomic_set(&event_count, 0);
78 gettimeofday(&start, NULL);
79 err = __machine__synthesize_threads(&session->machines.host,
80 NULL,
81 target, threads,
82 process_synthesized_event,
83 true, data_mmap,
84 nr_threads_synthesize);
85 if (err)
86 return err;
87
88 gettimeofday(&end, NULL);
89 timersub(&end, &start, &diff);
90 runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
91 update_stats(&time_stats, runtime_us);
92 update_stats(&event_stats, atomic_read(&event_count));
93 }
94
95 time_average = avg_stats(&time_stats);
96 time_stddev = stddev_stats(&time_stats);
97 printf(" Average %ssynthesis took: %.3f usec (+- %.3f usec)\n",
98 data_mmap ? "data " : "", time_average, time_stddev);
99
100 event_average = avg_stats(&event_stats);
101 event_stddev = stddev_stats(&event_stats);
102 printf(" Average num. events: %.3f (+- %.3f)\n",
103 event_average, event_stddev);
104
105 printf(" Average time per event %.3f usec\n",
106 time_average / event_average);
107 return 0;
108 }
109
run_single_threaded(void)110 static int run_single_threaded(void)
111 {
112 struct perf_session *session;
113 struct target target = {
114 .pid = "self",
115 };
116 struct perf_thread_map *threads;
117 int err;
118
119 perf_set_singlethreaded();
120 session = perf_session__new(NULL, NULL);
121 if (IS_ERR(session)) {
122 pr_err("Session creation failed.\n");
123 return PTR_ERR(session);
124 }
125 threads = thread_map__new_by_pid(getpid());
126 if (!threads) {
127 pr_err("Thread map creation failed.\n");
128 err = -ENOMEM;
129 goto err_out;
130 }
131
132 puts(
133 "Computing performance of single threaded perf event synthesis by\n"
134 "synthesizing events on the perf process itself:");
135
136 err = do_run_single_threaded(session, threads, &target, false);
137 if (err)
138 goto err_out;
139
140 err = do_run_single_threaded(session, threads, &target, true);
141
142 err_out:
143 if (threads)
144 perf_thread_map__put(threads);
145
146 perf_session__delete(session);
147 return err;
148 }
149
do_run_multi_threaded(struct target * target,unsigned int nr_threads_synthesize)150 static int do_run_multi_threaded(struct target *target,
151 unsigned int nr_threads_synthesize)
152 {
153 struct timeval start, end, diff;
154 u64 runtime_us;
155 unsigned int i;
156 double time_average, time_stddev, event_average, event_stddev;
157 int err;
158 struct stats time_stats, event_stats;
159 struct perf_session *session;
160
161 init_stats(&time_stats);
162 init_stats(&event_stats);
163 for (i = 0; i < multi_iterations; i++) {
164 session = perf_session__new(NULL, NULL);
165 if (IS_ERR(session))
166 return PTR_ERR(session);
167
168 atomic_set(&event_count, 0);
169 gettimeofday(&start, NULL);
170 err = __machine__synthesize_threads(&session->machines.host,
171 NULL,
172 target, NULL,
173 process_synthesized_event,
174 true, false,
175 nr_threads_synthesize);
176 if (err) {
177 perf_session__delete(session);
178 return err;
179 }
180
181 gettimeofday(&end, NULL);
182 timersub(&end, &start, &diff);
183 runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
184 update_stats(&time_stats, runtime_us);
185 update_stats(&event_stats, atomic_read(&event_count));
186 perf_session__delete(session);
187 }
188
189 time_average = avg_stats(&time_stats);
190 time_stddev = stddev_stats(&time_stats);
191 printf(" Average synthesis took: %.3f usec (+- %.3f usec)\n",
192 time_average, time_stddev);
193
194 event_average = avg_stats(&event_stats);
195 event_stddev = stddev_stats(&event_stats);
196 printf(" Average num. events: %.3f (+- %.3f)\n",
197 event_average, event_stddev);
198
199 printf(" Average time per event %.3f usec\n",
200 time_average / event_average);
201 return 0;
202 }
203
run_multi_threaded(void)204 static int run_multi_threaded(void)
205 {
206 struct target target = {
207 .cpu_list = "0"
208 };
209 unsigned int nr_threads_synthesize;
210 int err;
211
212 if (max_threads == UINT_MAX)
213 max_threads = sysconf(_SC_NPROCESSORS_ONLN);
214
215 puts(
216 "Computing performance of multi threaded perf event synthesis by\n"
217 "synthesizing events on CPU 0:");
218
219 for (nr_threads_synthesize = min_threads;
220 nr_threads_synthesize <= max_threads;
221 nr_threads_synthesize++) {
222 if (nr_threads_synthesize == 1)
223 perf_set_singlethreaded();
224 else
225 perf_set_multithreaded();
226
227 printf(" Number of synthesis threads: %u\n",
228 nr_threads_synthesize);
229
230 err = do_run_multi_threaded(&target, nr_threads_synthesize);
231 if (err)
232 return err;
233 }
234 perf_set_singlethreaded();
235 return 0;
236 }
237
bench_synthesize(int argc,const char ** argv)238 int bench_synthesize(int argc, const char **argv)
239 {
240 int err = 0;
241
242 argc = parse_options(argc, argv, options, bench_usage, 0);
243 if (argc) {
244 usage_with_options(bench_usage, options);
245 exit(EXIT_FAILURE);
246 }
247
248 /*
249 * If neither single threaded or multi-threaded are specified, default
250 * to running just single threaded.
251 */
252 if (!run_st && !run_mt)
253 run_st = true;
254
255 if (run_st)
256 err = run_single_threaded();
257
258 if (!err && run_mt)
259 err = run_multi_threaded();
260
261 return err;
262 }
263