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