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833ad6a0 MD |
1 | /* |
2 | * (C) Copyright 2009-2011 - | |
3 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
4 | * | |
5 | * LTTng performance monitoring counters (perf-counters) integration module. | |
6 | * | |
7 | * Dual LGPL v2.1/GPL v2 license. | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/perf_event.h> | |
13 | #include <linux/list.h> | |
c24a0d71 MD |
14 | #include <linux/string.h> |
15 | #include "ltt-events.h" | |
16 | #include "wrapper/ringbuffer/frontend_types.h" | |
17 | #include "wrapper/vmalloc.h" | |
18 | #include "ltt-tracer.h" | |
833ad6a0 | 19 | |
f1676205 MD |
20 | static |
21 | size_t perf_counter_get_size(size_t offset) | |
22 | { | |
23 | size_t size = 0; | |
24 | ||
25 | size += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); | |
26 | size += sizeof(uint64_t); | |
27 | return size; | |
28 | } | |
29 | ||
833ad6a0 MD |
30 | static |
31 | void perf_counter_record(struct lttng_ctx_field *field, | |
32 | struct lib_ring_buffer_ctx *ctx, | |
33 | struct ltt_channel *chan) | |
34 | { | |
35 | struct perf_event *event; | |
36 | uint64_t value; | |
37 | ||
2001023e | 38 | event = field->u.perf_counter->e[ctx->cpu]; |
0478c519 | 39 | if (likely(event)) { |
7b745a96 MD |
40 | if (unlikely(event->state == PERF_EVENT_STATE_ERROR)) { |
41 | value = 0; | |
42 | } else { | |
43 | event->pmu->read(event); | |
44 | value = local64_read(&event->count); | |
45 | } | |
f91fd73b MD |
46 | } else { |
47 | /* | |
48 | * Perf chooses not to be clever and not to support enabling a | |
49 | * perf counter before the cpu is brought up. Therefore, we need | |
50 | * to support having events coming (e.g. scheduler events) | |
51 | * before the counter is setup. Write an arbitrary 0 in this | |
52 | * case. | |
53 | */ | |
54 | value = 0; | |
55 | } | |
9e7e4892 | 56 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(value)); |
833ad6a0 MD |
57 | chan->ops->event_write(ctx, &value, sizeof(value)); |
58 | } | |
59 | ||
60 | static | |
61 | void overflow_callback(struct perf_event *event, int nmi, | |
62 | struct perf_sample_data *data, | |
63 | struct pt_regs *regs) | |
64 | { | |
65 | } | |
66 | ||
2dccf128 MD |
67 | static |
68 | void lttng_destroy_perf_counter_field(struct lttng_ctx_field *field) | |
69 | { | |
2001023e | 70 | struct perf_event **events = field->u.perf_counter->e; |
2dccf128 MD |
71 | int cpu; |
72 | ||
8289661d | 73 | get_online_cpus(); |
2dccf128 MD |
74 | for_each_online_cpu(cpu) |
75 | perf_event_release_kernel(events[cpu]); | |
8289661d MD |
76 | put_online_cpus(); |
77 | #ifdef CONFIG_HOTPLUG_CPU | |
2001023e | 78 | unregister_cpu_notifier(&field->u.perf_counter->nb); |
8289661d | 79 | #endif |
c24a0d71 | 80 | kfree(field->event_field.name); |
2001023e | 81 | kfree(field->u.perf_counter->attr); |
2dccf128 | 82 | kfree(events); |
2001023e | 83 | kfree(field->u.perf_counter); |
2dccf128 MD |
84 | } |
85 | ||
8289661d MD |
86 | #ifdef CONFIG_HOTPLUG_CPU |
87 | ||
88 | /** | |
89 | * lttng_perf_counter_hp_callback - CPU hotplug callback | |
90 | * @nb: notifier block | |
91 | * @action: hotplug action to take | |
92 | * @hcpu: CPU number | |
93 | * | |
94 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
95 | * | |
96 | * We can setup perf counters when the cpu is online (up prepare seems to be too | |
97 | * soon). | |
98 | */ | |
99 | static | |
100 | int __cpuinit lttng_perf_counter_cpu_hp_callback(struct notifier_block *nb, | |
101 | unsigned long action, | |
102 | void *hcpu) | |
103 | { | |
104 | unsigned int cpu = (unsigned long) hcpu; | |
2001023e MD |
105 | struct lttng_perf_counter_field *perf_field = |
106 | container_of(nb, struct lttng_perf_counter_field, nb); | |
107 | struct perf_event **events = perf_field->e; | |
108 | struct perf_event_attr *attr = perf_field->attr; | |
f91fd73b | 109 | struct perf_event *pevent; |
8289661d | 110 | |
2001023e | 111 | if (!perf_field->hp_enable) |
8289661d MD |
112 | return NOTIFY_OK; |
113 | ||
114 | switch (action) { | |
115 | case CPU_ONLINE: | |
116 | case CPU_ONLINE_FROZEN: | |
f91fd73b | 117 | pevent = perf_event_create_kernel_counter(attr, |
8289661d | 118 | cpu, NULL, overflow_callback); |
0478c519 | 119 | if (!pevent || IS_ERR(pevent)) |
8289661d | 120 | return NOTIFY_BAD; |
7b745a96 MD |
121 | if (pevent->state == PERF_EVENT_STATE_ERROR) { |
122 | perf_event_release_kernel(pevent); | |
123 | return NOTIFY_BAD; | |
124 | } | |
f91fd73b MD |
125 | barrier(); /* Create perf counter before setting event */ |
126 | events[cpu] = pevent; | |
8289661d MD |
127 | break; |
128 | case CPU_UP_CANCELED: | |
129 | case CPU_UP_CANCELED_FROZEN: | |
130 | case CPU_DEAD: | |
131 | case CPU_DEAD_FROZEN: | |
f91fd73b MD |
132 | pevent = events[cpu]; |
133 | events[cpu] = NULL; | |
134 | barrier(); /* NULLify event before perf counter teardown */ | |
135 | perf_event_release_kernel(pevent); | |
8289661d MD |
136 | break; |
137 | } | |
138 | return NOTIFY_OK; | |
139 | } | |
140 | ||
141 | #endif | |
142 | ||
833ad6a0 MD |
143 | int lttng_add_perf_counter_to_ctx(uint32_t type, |
144 | uint64_t config, | |
c24a0d71 | 145 | const char *name, |
2dccf128 | 146 | struct lttng_ctx **ctx) |
833ad6a0 MD |
147 | { |
148 | struct lttng_ctx_field *field; | |
2001023e | 149 | struct lttng_perf_counter_field *perf_field; |
833ad6a0 MD |
150 | struct perf_event **events; |
151 | struct perf_event_attr *attr; | |
152 | int ret; | |
153 | int cpu; | |
c24a0d71 | 154 | char *name_alloc; |
833ad6a0 MD |
155 | |
156 | events = kzalloc(num_possible_cpus() * sizeof(*events), GFP_KERNEL); | |
157 | if (!events) | |
158 | return -ENOMEM; | |
159 | ||
2001023e | 160 | attr = kzalloc(sizeof(struct perf_event_attr), GFP_KERNEL); |
833ad6a0 MD |
161 | if (!attr) { |
162 | ret = -ENOMEM; | |
163 | goto error_attr; | |
164 | } | |
165 | ||
166 | attr->type = type; | |
167 | attr->config = config; | |
168 | attr->size = sizeof(struct perf_event_attr); | |
169 | attr->pinned = 1; | |
170 | attr->disabled = 0; | |
171 | ||
2001023e MD |
172 | perf_field = kzalloc(sizeof(struct lttng_perf_counter_field), GFP_KERNEL); |
173 | if (!perf_field) { | |
174 | ret = -ENOMEM; | |
175 | goto error_alloc_perf_field; | |
176 | } | |
177 | perf_field->e = events; | |
178 | perf_field->attr = attr; | |
179 | ||
c24a0d71 | 180 | name_alloc = kstrdup(name, GFP_KERNEL); |
bef96e48 MD |
181 | if (!name_alloc) { |
182 | ret = -ENOMEM; | |
c24a0d71 | 183 | goto name_alloc_error; |
bef96e48 | 184 | } |
c24a0d71 | 185 | |
2dccf128 MD |
186 | field = lttng_append_context(ctx); |
187 | if (!field) { | |
188 | ret = -ENOMEM; | |
8289661d | 189 | goto append_context_error; |
833ad6a0 | 190 | } |
2001023e | 191 | if (lttng_find_context(*ctx, name_alloc)) { |
44252f0f MD |
192 | ret = -EEXIST; |
193 | goto find_error; | |
194 | } | |
8289661d MD |
195 | |
196 | #ifdef CONFIG_HOTPLUG_CPU | |
2001023e | 197 | perf_field->nb.notifier_call = |
8289661d | 198 | lttng_perf_counter_cpu_hp_callback; |
2001023e MD |
199 | perf_field->nb.priority = 0; |
200 | register_cpu_notifier(&perf_field->nb); | |
8289661d MD |
201 | #endif |
202 | ||
203 | get_online_cpus(); | |
204 | for_each_online_cpu(cpu) { | |
205 | events[cpu] = perf_event_create_kernel_counter(attr, | |
206 | cpu, NULL, overflow_callback); | |
0478c519 | 207 | if (!events[cpu] || IS_ERR(events[cpu])) { |
8289661d MD |
208 | ret = -EINVAL; |
209 | goto counter_error; | |
210 | } | |
7b745a96 MD |
211 | if (events[cpu]->state == PERF_EVENT_STATE_ERROR) { |
212 | ret = -EBUSY; | |
213 | goto counter_busy; | |
214 | } | |
8289661d MD |
215 | } |
216 | put_online_cpus(); | |
217 | ||
2dccf128 | 218 | field->destroy = lttng_destroy_perf_counter_field; |
833ad6a0 | 219 | |
c24a0d71 | 220 | field->event_field.name = name_alloc; |
8070f5c0 MD |
221 | field->event_field.type.atype = atype_integer; |
222 | field->event_field.type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT; | |
223 | field->event_field.type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT; | |
224 | field->event_field.type.u.basic.integer.signedness = is_signed_type(unsigned long); | |
225 | field->event_field.type.u.basic.integer.reverse_byte_order = 0; | |
226 | field->event_field.type.u.basic.integer.base = 10; | |
227 | field->event_field.type.u.basic.integer.encoding = lttng_encode_none; | |
f1676205 MD |
228 | field->get_size = perf_counter_get_size; |
229 | field->record = perf_counter_record; | |
2001023e MD |
230 | field->u.perf_counter = perf_field; |
231 | perf_field->hp_enable = 1; | |
833ad6a0 MD |
232 | |
233 | wrapper_vmalloc_sync_all(); | |
234 | return 0; | |
235 | ||
7b745a96 | 236 | counter_busy: |
8289661d | 237 | counter_error: |
833ad6a0 | 238 | for_each_online_cpu(cpu) { |
0478c519 | 239 | if (events[cpu] && !IS_ERR(events[cpu])) |
833ad6a0 MD |
240 | perf_event_release_kernel(events[cpu]); |
241 | } | |
8289661d MD |
242 | put_online_cpus(); |
243 | #ifdef CONFIG_HOTPLUG_CPU | |
2001023e | 244 | unregister_cpu_notifier(&perf_field->nb); |
8289661d | 245 | #endif |
44252f0f | 246 | find_error: |
8289661d MD |
247 | lttng_remove_context_field(ctx, field); |
248 | append_context_error: | |
249 | kfree(name_alloc); | |
250 | name_alloc_error: | |
2001023e MD |
251 | kfree(perf_field); |
252 | error_alloc_perf_field: | |
833ad6a0 MD |
253 | kfree(attr); |
254 | error_attr: | |
255 | kfree(events); | |
256 | return ret; | |
257 | } | |
258 | ||
833ad6a0 MD |
259 | MODULE_LICENSE("GPL and additional rights"); |
260 | MODULE_AUTHOR("Mathieu Desnoyers"); | |
261 | MODULE_DESCRIPTION("Linux Trace Toolkit Perf Support"); |