1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2021 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org> 4 */ 5 #define _GNU_SOURCE 6 #include <sys/types.h> 7 #include <sys/stat.h> 8 #include <pthread.h> 9 #include <stdlib.h> 10 #include <string.h> 11 #include <unistd.h> 12 #include <errno.h> 13 #include <fcntl.h> 14 #include <stdio.h> 15 #include <sched.h> 16 17 #include "timerlat.h" 18 #include "timerlat_aa.h" 19 #include "timerlat_bpf.h" 20 21 #define DEFAULT_TIMERLAT_PERIOD 1000 /* 1ms */ 22 23 static int dma_latency_fd = -1; 24 25 /* 26 * timerlat_apply_config - apply common configs to the initialized tool 27 */ 28 int 29 timerlat_apply_config(struct osnoise_tool *tool, struct timerlat_params *params) 30 { 31 int retval; 32 33 /* 34 * Try to enable BPF, unless disabled explicitly. 35 * If BPF enablement fails, fall back to tracefs mode. 36 */ 37 if (getenv("RTLA_NO_BPF") && strncmp(getenv("RTLA_NO_BPF"), "1", 2) == 0) { 38 debug_msg("RTLA_NO_BPF set, disabling BPF\n"); 39 params->mode = TRACING_MODE_TRACEFS; 40 } else if (!tep_find_event_by_name(tool->trace.tep, "osnoise", "timerlat_sample")) { 41 debug_msg("osnoise:timerlat_sample missing, disabling BPF\n"); 42 params->mode = TRACING_MODE_TRACEFS; 43 } else { 44 retval = timerlat_bpf_init(params); 45 if (retval) { 46 debug_msg("Could not enable BPF\n"); 47 params->mode = TRACING_MODE_TRACEFS; 48 } 49 } 50 51 retval = osnoise_set_timerlat_period_us(tool->context, 52 params->timerlat_period_us ? 53 params->timerlat_period_us : 54 DEFAULT_TIMERLAT_PERIOD); 55 if (retval) { 56 err_msg("Failed to set timerlat period\n"); 57 goto out_err; 58 } 59 60 61 retval = osnoise_set_print_stack(tool->context, params->print_stack); 62 if (retval) { 63 err_msg("Failed to set print stack\n"); 64 goto out_err; 65 } 66 67 /* 68 * If the user did not specify a type of thread, try user-threads first. 69 * Fall back to kernel threads otherwise. 70 */ 71 if (!params->common.kernel_workload && !params->common.user_data) { 72 retval = tracefs_file_exists(NULL, "osnoise/per_cpu/cpu0/timerlat_fd"); 73 if (retval) { 74 debug_msg("User-space interface detected, setting user-threads\n"); 75 params->common.user_workload = 1; 76 params->common.user_data = 1; 77 } else { 78 debug_msg("User-space interface not detected, setting kernel-threads\n"); 79 params->common.kernel_workload = 1; 80 } 81 } 82 83 return common_apply_config(tool, ¶ms->common); 84 85 out_err: 86 return -1; 87 } 88 89 int timerlat_enable(struct osnoise_tool *tool) 90 { 91 struct timerlat_params *params = to_timerlat_params(tool->params); 92 int retval, nr_cpus, i; 93 94 if (params->dma_latency >= 0) { 95 dma_latency_fd = set_cpu_dma_latency(params->dma_latency); 96 if (dma_latency_fd < 0) { 97 err_msg("Could not set /dev/cpu_dma_latency.\n"); 98 return -1; 99 } 100 } 101 102 if (params->deepest_idle_state >= -1) { 103 if (!have_libcpupower_support()) { 104 err_msg("rtla built without libcpupower, --deepest-idle-state is not supported\n"); 105 return -1; 106 } 107 108 nr_cpus = sysconf(_SC_NPROCESSORS_CONF); 109 110 for_each_monitored_cpu(i, nr_cpus, ¶ms->common) { 111 if (save_cpu_idle_disable_state(i) < 0) { 112 err_msg("Could not save cpu idle state.\n"); 113 return -1; 114 } 115 if (set_deepest_cpu_idle_state(i, params->deepest_idle_state) < 0) { 116 err_msg("Could not set deepest cpu idle state.\n"); 117 return -1; 118 } 119 } 120 } 121 122 if (!params->no_aa) { 123 tool->aa = osnoise_init_tool("timerlat_aa"); 124 if (!tool->aa) 125 return -1; 126 127 retval = timerlat_aa_init(tool->aa, params->dump_tasks); 128 if (retval) { 129 err_msg("Failed to enable the auto analysis instance\n"); 130 return retval; 131 } 132 133 retval = enable_tracer_by_name(tool->aa->trace.inst, "timerlat"); 134 if (retval) { 135 err_msg("Failed to enable aa tracer\n"); 136 return retval; 137 } 138 } 139 140 if (params->common.warmup > 0) { 141 debug_msg("Warming up for %d seconds\n", params->common.warmup); 142 sleep(params->common.warmup); 143 if (stop_tracing) 144 return -1; 145 } 146 147 /* 148 * Start the tracers here, after having set all instances. 149 * 150 * Let the trace instance start first for the case of hitting a stop 151 * tracing while enabling other instances. The trace instance is the 152 * one with most valuable information. 153 */ 154 if (tool->record) 155 trace_instance_start(&tool->record->trace); 156 if (!params->no_aa) 157 trace_instance_start(&tool->aa->trace); 158 if (params->mode == TRACING_MODE_TRACEFS) { 159 trace_instance_start(&tool->trace); 160 } else { 161 retval = timerlat_bpf_attach(); 162 if (retval) { 163 err_msg("Error attaching BPF program\n"); 164 return retval; 165 } 166 } 167 168 /* 169 * In tracefs and mixed mode, timerlat tracer handles stopping 170 * on threshold 171 */ 172 if (params->mode != TRACING_MODE_BPF) { 173 retval = osn_set_stop(tool); 174 if (retval) 175 return retval; 176 } 177 178 return 0; 179 } 180 181 void timerlat_analyze(struct osnoise_tool *tool, bool stopped) 182 { 183 struct timerlat_params *params = to_timerlat_params(tool->params); 184 185 if (stopped) { 186 if (!params->no_aa) 187 timerlat_auto_analysis(params->common.stop_us, 188 params->common.stop_total_us); 189 } else if (params->common.aa_only) { 190 char *max_lat; 191 192 /* 193 * If the trace did not stop with --aa-only, at least print 194 * the max known latency. 195 */ 196 max_lat = tracefs_instance_file_read(trace_inst->inst, "tracing_max_latency", NULL); 197 if (max_lat) { 198 printf(" Max latency was %s\n", max_lat); 199 free(max_lat); 200 } 201 } 202 } 203 204 void timerlat_free(struct osnoise_tool *tool) 205 { 206 struct timerlat_params *params = to_timerlat_params(tool->params); 207 int nr_cpus = sysconf(_SC_NPROCESSORS_CONF); 208 int i; 209 210 timerlat_aa_destroy(); 211 if (dma_latency_fd >= 0) 212 close(dma_latency_fd); 213 if (params->deepest_idle_state >= -1) { 214 for_each_monitored_cpu(i, nr_cpus, ¶ms->common) { 215 restore_cpu_idle_disable_state(i); 216 } 217 } 218 219 osnoise_destroy_tool(tool->aa); 220 221 if (params->mode != TRACING_MODE_TRACEFS) 222 timerlat_bpf_destroy(); 223 free_cpu_idle_disable_states(); 224 } 225 226 static void timerlat_usage(int err) 227 { 228 int i; 229 230 static const char * const msg[] = { 231 "", 232 "timerlat version " VERSION, 233 "", 234 " usage: [rtla] timerlat [MODE] ...", 235 "", 236 " modes:", 237 " top - prints the summary from timerlat tracer", 238 " hist - prints a histogram of timer latencies", 239 "", 240 "if no MODE is given, the top mode is called, passing the arguments", 241 NULL, 242 }; 243 244 for (i = 0; msg[i]; i++) 245 fprintf(stderr, "%s\n", msg[i]); 246 exit(err); 247 } 248 249 int timerlat_main(int argc, char *argv[]) 250 { 251 if (argc == 0) 252 goto usage; 253 254 /* 255 * if timerlat was called without any argument, run the 256 * default cmdline. 257 */ 258 if (argc == 1) { 259 run_tool(&timerlat_top_ops, argc, argv); 260 exit(0); 261 } 262 263 if ((strcmp(argv[1], "-h") == 0) || (strcmp(argv[1], "--help") == 0)) { 264 timerlat_usage(0); 265 } else if (strncmp(argv[1], "-", 1) == 0) { 266 /* the user skipped the tool, call the default one */ 267 run_tool(&timerlat_top_ops, argc, argv); 268 exit(0); 269 } else if (strcmp(argv[1], "top") == 0) { 270 run_tool(&timerlat_top_ops, argc-1, &argv[1]); 271 exit(0); 272 } else if (strcmp(argv[1], "hist") == 0) { 273 run_tool(&timerlat_hist_ops, argc-1, &argv[1]); 274 exit(0); 275 } 276 277 usage: 278 timerlat_usage(1); 279 exit(1); 280 } 281