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 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 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 } 109 110 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 } 149 150 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 } 203 204 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 } 237 238 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