1 // SPDX-License-Identifier: GPL-2.0
2 #include "util/debug.h"
3 #include "util/evlist.h"
4 #include "util/machine.h"
5 #include "util/map.h"
6 #include "util/symbol.h"
7 #include "util/target.h"
8 #include "util/thread_map.h"
9 #include "util/lock-contention.h"
10 #include <linux/zalloc.h>
11 #include <linux/string.h>
12 #include <bpf/bpf.h>
13
14 #include "bpf_skel/lock_contention.skel.h"
15
16 static struct lock_contention_bpf *skel;
17
18 struct lock_contention_data {
19 u64 total_time;
20 u64 min_time;
21 u64 max_time;
22 u32 count;
23 u32 flags;
24 };
25
lock_contention_prepare(struct lock_contention * con)26 int lock_contention_prepare(struct lock_contention *con)
27 {
28 int i, fd;
29 int ncpus = 1, ntasks = 1;
30 struct evlist *evlist = con->evlist;
31 struct target *target = con->target;
32
33 skel = lock_contention_bpf__open();
34 if (!skel) {
35 pr_err("Failed to open lock-contention BPF skeleton\n");
36 return -1;
37 }
38
39 bpf_map__set_value_size(skel->maps.stacks, con->max_stack * sizeof(u64));
40 bpf_map__set_max_entries(skel->maps.stacks, con->map_nr_entries);
41 bpf_map__set_max_entries(skel->maps.lock_stat, con->map_nr_entries);
42
43 if (target__has_cpu(target))
44 ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);
45 if (target__has_task(target))
46 ntasks = perf_thread_map__nr(evlist->core.threads);
47
48 bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
49 bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
50
51 if (lock_contention_bpf__load(skel) < 0) {
52 pr_err("Failed to load lock-contention BPF skeleton\n");
53 return -1;
54 }
55
56 if (target__has_cpu(target)) {
57 u32 cpu;
58 u8 val = 1;
59
60 skel->bss->has_cpu = 1;
61 fd = bpf_map__fd(skel->maps.cpu_filter);
62
63 for (i = 0; i < ncpus; i++) {
64 cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu;
65 bpf_map_update_elem(fd, &cpu, &val, BPF_ANY);
66 }
67 }
68
69 if (target__has_task(target)) {
70 u32 pid;
71 u8 val = 1;
72
73 skel->bss->has_task = 1;
74 fd = bpf_map__fd(skel->maps.task_filter);
75
76 for (i = 0; i < ntasks; i++) {
77 pid = perf_thread_map__pid(evlist->core.threads, i);
78 bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
79 }
80 }
81
82 if (target__none(target) && evlist->workload.pid > 0) {
83 u32 pid = evlist->workload.pid;
84 u8 val = 1;
85
86 skel->bss->has_task = 1;
87 fd = bpf_map__fd(skel->maps.task_filter);
88 bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
89 }
90
91 skel->bss->stack_skip = con->stack_skip;
92
93 lock_contention_bpf__attach(skel);
94 return 0;
95 }
96
lock_contention_start(void)97 int lock_contention_start(void)
98 {
99 skel->bss->enabled = 1;
100 return 0;
101 }
102
lock_contention_stop(void)103 int lock_contention_stop(void)
104 {
105 skel->bss->enabled = 0;
106 return 0;
107 }
108
lock_contention_read(struct lock_contention * con)109 int lock_contention_read(struct lock_contention *con)
110 {
111 int fd, stack;
112 s32 prev_key, key;
113 struct lock_contention_data data;
114 struct lock_stat *st;
115 struct machine *machine = con->machine;
116 u64 stack_trace[con->max_stack];
117
118 fd = bpf_map__fd(skel->maps.lock_stat);
119 stack = bpf_map__fd(skel->maps.stacks);
120
121 con->lost = skel->bss->lost;
122
123 prev_key = 0;
124 while (!bpf_map_get_next_key(fd, &prev_key, &key)) {
125 struct map *kmap;
126 struct symbol *sym;
127 int idx = 0;
128
129 bpf_map_lookup_elem(fd, &key, &data);
130 st = zalloc(sizeof(*st));
131 if (st == NULL)
132 return -1;
133
134 st->nr_contended = data.count;
135 st->wait_time_total = data.total_time;
136 st->wait_time_max = data.max_time;
137 st->wait_time_min = data.min_time;
138
139 if (data.count)
140 st->avg_wait_time = data.total_time / data.count;
141
142 st->flags = data.flags;
143
144 bpf_map_lookup_elem(stack, &key, stack_trace);
145
146 /* skip lock internal functions */
147 while (is_lock_function(machine, stack_trace[idx]) &&
148 idx < con->max_stack - 1)
149 idx++;
150
151 st->addr = stack_trace[idx];
152 sym = machine__find_kernel_symbol(machine, st->addr, &kmap);
153
154 if (sym) {
155 unsigned long offset;
156 int ret = 0;
157
158 offset = kmap->map_ip(kmap, st->addr) - sym->start;
159
160 if (offset)
161 ret = asprintf(&st->name, "%s+%#lx", sym->name, offset);
162 else
163 st->name = strdup(sym->name);
164
165 if (ret < 0 || st->name == NULL)
166 return -1;
167 } else if (asprintf(&st->name, "%#lx", (unsigned long)st->addr) < 0) {
168 free(st);
169 return -1;
170 }
171
172 if (verbose) {
173 st->callstack = memdup(stack_trace, sizeof(stack_trace));
174 if (st->callstack == NULL) {
175 free(st);
176 return -1;
177 }
178 }
179
180 hlist_add_head(&st->hash_entry, con->result);
181 prev_key = key;
182 }
183
184 return 0;
185 }
186
lock_contention_finish(void)187 int lock_contention_finish(void)
188 {
189 if (skel) {
190 skel->bss->enabled = 0;
191 lock_contention_bpf__destroy(skel);
192 }
193
194 return 0;
195 }
196