1// SPDX-License-Identifier: GPL-2.0
2/*
3 * bpf_kwork.c
4 *
5 * Copyright (c) 2022 Huawei Inc, Yang Jihong <yangjihong1@huawei.com>
6 */
7
8#include <time.h>
9#include <fcntl.h>
10#include <signal.h>
11#include <stdio.h>
12#include <unistd.h>
13
14#include <linux/time64.h>
15
16#include "util/debug.h"
17#include "util/evsel.h"
18#include "util/kwork.h"
19
20#include <bpf/bpf.h>
21#include <perf/cpumap.h>
22
23#include "util/bpf_skel/kwork_trace.skel.h"
24
25/*
26 * This should be in sync with "util/kwork_trace.bpf.c"
27 */
28#define MAX_KWORKNAME 128
29
30struct work_key {
31 u32 type;
32 u32 cpu;
33 u64 id;
34};
35
36struct report_data {
37 u64 nr;
38 u64 total_time;
39 u64 max_time;
40 u64 max_time_start;
41 u64 max_time_end;
42};
43
44struct kwork_class_bpf {
45 struct kwork_class *class;
46
47 void (*load_prepare)(struct perf_kwork *kwork);
48 int (*get_work_name)(struct work_key *key, char **ret_name);
49};
50
51static struct kwork_trace_bpf *skel;
52
53static struct timespec ts_start;
54static struct timespec ts_end;
55
56void perf_kwork__trace_start(void)
57{
58 clock_gettime(CLOCK_MONOTONIC, &ts_start);
59 skel->bss->enabled = 1;
60}
61
62void perf_kwork__trace_finish(void)
63{
64 clock_gettime(CLOCK_MONOTONIC, &ts_end);
65 skel->bss->enabled = 0;
66}
67
68static int get_work_name_from_map(struct work_key *key, char **ret_name)
69{
70 char name[MAX_KWORKNAME] = { 0 };
71 int fd = bpf_map__fd(skel->maps.perf_kwork_names);
72
73 *ret_name = NULL;
74
75 if (fd < 0) {
76 pr_debug("Invalid names map fd\n");
77 return 0;
78 }
79
80 if ((bpf_map_lookup_elem(fd, key, name) == 0) && (strlen(name) != 0)) {
81 *ret_name = strdup(name);
82 if (*ret_name == NULL) {
83 pr_err("Failed to copy work name\n");
84 return -1;
85 }
86 }
87
88 return 0;
89}
90
91static void irq_load_prepare(struct perf_kwork *kwork)
92{
93 if (kwork->report == KWORK_REPORT_RUNTIME) {
94 bpf_program__set_autoload(skel->progs.report_irq_handler_entry, true);
95 bpf_program__set_autoload(skel->progs.report_irq_handler_exit, true);
96 }
97}
98
99static struct kwork_class_bpf kwork_irq_bpf = {
100 .load_prepare = irq_load_prepare,
101 .get_work_name = get_work_name_from_map,
102};
103
104static void softirq_load_prepare(struct perf_kwork *kwork)
105{
106 if (kwork->report == KWORK_REPORT_RUNTIME) {
107 bpf_program__set_autoload(skel->progs.report_softirq_entry, true);
108 bpf_program__set_autoload(skel->progs.report_softirq_exit, true);
109 } else if (kwork->report == KWORK_REPORT_LATENCY) {
110 bpf_program__set_autoload(skel->progs.latency_softirq_raise, true);
111 bpf_program__set_autoload(skel->progs.latency_softirq_entry, true);
112 }
113}
114
115static struct kwork_class_bpf kwork_softirq_bpf = {
116 .load_prepare = softirq_load_prepare,
117 .get_work_name = get_work_name_from_map,
118};
119
120static void workqueue_load_prepare(struct perf_kwork *kwork)
121{
122 if (kwork->report == KWORK_REPORT_RUNTIME) {
123 bpf_program__set_autoload(skel->progs.report_workqueue_execute_start, true);
124 bpf_program__set_autoload(skel->progs.report_workqueue_execute_end, true);
125 } else if (kwork->report == KWORK_REPORT_LATENCY) {
126 bpf_program__set_autoload(skel->progs.latency_workqueue_activate_work, true);
127 bpf_program__set_autoload(skel->progs.latency_workqueue_execute_start, true);
128 }
129}
130
131static struct kwork_class_bpf kwork_workqueue_bpf = {
132 .load_prepare = workqueue_load_prepare,
133 .get_work_name = get_work_name_from_map,
134};
135
136static struct kwork_class_bpf *
137kwork_class_bpf_supported_list[KWORK_CLASS_MAX] = {
138 [KWORK_CLASS_IRQ] = &kwork_irq_bpf,
139 [KWORK_CLASS_SOFTIRQ] = &kwork_softirq_bpf,
140 [KWORK_CLASS_WORKQUEUE] = &kwork_workqueue_bpf,
141};
142
143static bool valid_kwork_class_type(enum kwork_class_type type)
144{
145 return type >= 0 && type < KWORK_CLASS_MAX ? true : false;
146}
147
148static int setup_filters(struct perf_kwork *kwork)
149{
150 u8 val = 1;
151 int i, nr_cpus, key, fd;
152 struct perf_cpu_map *map;
153
154 if (kwork->cpu_list != NULL) {
155 fd = bpf_map__fd(skel->maps.perf_kwork_cpu_filter);
156 if (fd < 0) {
157 pr_debug("Invalid cpu filter fd\n");
158 return -1;
159 }
160
161 map = perf_cpu_map__new(kwork->cpu_list);
162 if (map == NULL) {
163 pr_debug("Invalid cpu_list\n");
164 return -1;
165 }
166
167 nr_cpus = libbpf_num_possible_cpus();
168 for (i = 0; i < perf_cpu_map__nr(map); i++) {
169 struct perf_cpu cpu = perf_cpu_map__cpu(map, i);
170
171 if (cpu.cpu >= nr_cpus) {
172 perf_cpu_map__put(map);
173 pr_err("Requested cpu %d too large\n", cpu.cpu);
174 return -1;
175 }
176 bpf_map_update_elem(fd, &cpu.cpu, &val, BPF_ANY);
177 }
178 perf_cpu_map__put(map);
179
180 skel->bss->has_cpu_filter = 1;
181 }
182
183 if (kwork->profile_name != NULL) {
184 if (strlen(kwork->profile_name) >= MAX_KWORKNAME) {
185 pr_err("Requested name filter %s too large, limit to %d\n",
186 kwork->profile_name, MAX_KWORKNAME - 1);
187 return -1;
188 }
189
190 fd = bpf_map__fd(skel->maps.perf_kwork_name_filter);
191 if (fd < 0) {
192 pr_debug("Invalid name filter fd\n");
193 return -1;
194 }
195
196 key = 0;
197 bpf_map_update_elem(fd, &key, kwork->profile_name, BPF_ANY);
198
199 skel->bss->has_name_filter = 1;
200 }
201
202 return 0;
203}
204
205int perf_kwork__trace_prepare_bpf(struct perf_kwork *kwork)
206{
207 struct bpf_program *prog;
208 struct kwork_class *class;
209 struct kwork_class_bpf *class_bpf;
210 enum kwork_class_type type;
211
212 skel = kwork_trace_bpf__open();
213 if (!skel) {
214 pr_debug("Failed to open kwork trace skeleton\n");
215 return -1;
216 }
217
218 /*
219 * set all progs to non-autoload,
220 * then set corresponding progs according to config
221 */
222 bpf_object__for_each_program(prog, skel->obj)
223 bpf_program__set_autoload(prog, false);
224
225 list_for_each_entry(class, &kwork->class_list, list) {
226 type = class->type;
227 if (!valid_kwork_class_type(type: type) ||
228 (kwork_class_bpf_supported_list[type] == NULL)) {
229 pr_err("Unsupported bpf trace class %s\n", class->name);
230 goto out;
231 }
232
233 class_bpf = kwork_class_bpf_supported_list[type];
234 class_bpf->class = class;
235
236 if (class_bpf->load_prepare != NULL)
237 class_bpf->load_prepare(kwork);
238 }
239
240 if (kwork_trace_bpf__load(skel)) {
241 pr_debug("Failed to load kwork trace skeleton\n");
242 goto out;
243 }
244
245 if (setup_filters(kwork))
246 goto out;
247
248 if (kwork_trace_bpf__attach(skel)) {
249 pr_debug("Failed to attach kwork trace skeleton\n");
250 goto out;
251 }
252
253 return 0;
254
255out:
256 kwork_trace_bpf__destroy(skel);
257 return -1;
258}
259
260static int add_work(struct perf_kwork *kwork,
261 struct work_key *key,
262 struct report_data *data)
263{
264 struct kwork_work *work;
265 struct kwork_class_bpf *bpf_trace;
266 struct kwork_work tmp = {
267 .id = key->id,
268 .name = NULL,
269 .cpu = key->cpu,
270 };
271 enum kwork_class_type type = key->type;
272
273 if (!valid_kwork_class_type(type: type)) {
274 pr_debug("Invalid class type %d to add work\n", type);
275 return -1;
276 }
277
278 bpf_trace = kwork_class_bpf_supported_list[type];
279 tmp.class = bpf_trace->class;
280
281 if ((bpf_trace->get_work_name != NULL) &&
282 (bpf_trace->get_work_name(key, &tmp.name)))
283 return -1;
284
285 work = perf_kwork_add_work(kwork, tmp.class, &tmp);
286 if (work == NULL)
287 return -1;
288
289 if (kwork->report == KWORK_REPORT_RUNTIME) {
290 work->nr_atoms = data->nr;
291 work->total_runtime = data->total_time;
292 work->max_runtime = data->max_time;
293 work->max_runtime_start = data->max_time_start;
294 work->max_runtime_end = data->max_time_end;
295 } else if (kwork->report == KWORK_REPORT_LATENCY) {
296 work->nr_atoms = data->nr;
297 work->total_latency = data->total_time;
298 work->max_latency = data->max_time;
299 work->max_latency_start = data->max_time_start;
300 work->max_latency_end = data->max_time_end;
301 } else {
302 pr_debug("Invalid bpf report type %d\n", kwork->report);
303 return -1;
304 }
305
306 kwork->timestart = (u64)ts_start.tv_sec * NSEC_PER_SEC + ts_start.tv_nsec;
307 kwork->timeend = (u64)ts_end.tv_sec * NSEC_PER_SEC + ts_end.tv_nsec;
308
309 return 0;
310}
311
312int perf_kwork__report_read_bpf(struct perf_kwork *kwork)
313{
314 struct report_data data;
315 struct work_key key = {
316 .type = 0,
317 .cpu = 0,
318 .id = 0,
319 };
320 struct work_key prev = {
321 .type = 0,
322 .cpu = 0,
323 .id = 0,
324 };
325 int fd = bpf_map__fd(skel->maps.perf_kwork_report);
326
327 if (fd < 0) {
328 pr_debug("Invalid report fd\n");
329 return -1;
330 }
331
332 while (!bpf_map_get_next_key(fd, &prev, &key)) {
333 if ((bpf_map_lookup_elem(fd, &key, &data)) != 0) {
334 pr_debug("Failed to lookup report elem\n");
335 return -1;
336 }
337
338 if ((data.nr != 0) && (add_work(kwork, key: &key, data: &data) != 0))
339 return -1;
340
341 prev = key;
342 }
343 return 0;
344}
345
346void perf_kwork__report_cleanup_bpf(void)
347{
348 kwork_trace_bpf__destroy(skel);
349}
350

source code of linux/tools/perf/util/bpf_kwork.c