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c7ea8487 | 1 | /* |
c0c0989a MJ |
2 | * SPDX-License-Identifier: LGPL-2.1-only |
3 | * | |
4 | * Copyright (C) 2009-2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
c7ea8487 MD |
5 | * |
6 | * LTTng UST CPU id context. | |
7 | * | |
8 | * Note: threads can be migrated at any point while executing the | |
9 | * tracepoint probe. This means the CPU id field (and filter) is only | |
10 | * statistical. For instance, even though a user might select a | |
11 | * cpu_id==1 filter, there may be few events recorded into the channel | |
12 | * appearing from other CPUs, due to migration. | |
c7ea8487 MD |
13 | */ |
14 | ||
3fbec7dc | 15 | #define _LGPL_SOURCE |
b4051ad8 | 16 | #include <stddef.h> |
c7ea8487 MD |
17 | #include <sys/types.h> |
18 | #include <unistd.h> | |
19 | #include <lttng/ust-events.h> | |
20 | #include <lttng/ust-tracer.h> | |
21 | #include <lttng/ringbuffer-config.h> | |
22 | #include "../libringbuffer/getcpu.h" | |
23 | ||
24 | static | |
53569322 | 25 | size_t cpu_id_get_size(struct lttng_ctx_field *field, size_t offset) |
c7ea8487 MD |
26 | { |
27 | size_t size = 0; | |
28 | ||
29 | size += lib_ring_buffer_align(offset, lttng_alignof(int)); | |
30 | size += sizeof(int); | |
31 | return size; | |
32 | } | |
33 | ||
34 | static | |
35 | void cpu_id_record(struct lttng_ctx_field *field, | |
36 | struct lttng_ust_lib_ring_buffer_ctx *ctx, | |
37 | struct lttng_channel *chan) | |
38 | { | |
39 | int cpu; | |
40 | ||
41 | cpu = lttng_ust_get_cpu(); | |
42 | lib_ring_buffer_align_ctx(ctx, lttng_alignof(cpu)); | |
43 | chan->ops->event_write(ctx, &cpu, sizeof(cpu)); | |
44 | } | |
45 | ||
46 | static | |
47 | void cpu_id_get_value(struct lttng_ctx_field *field, | |
53569322 | 48 | struct lttng_ctx_value *value) |
c7ea8487 | 49 | { |
6e9ac4ae | 50 | value->u.s64 = lttng_ust_get_cpu(); |
c7ea8487 MD |
51 | } |
52 | ||
53 | int lttng_add_cpu_id_to_ctx(struct lttng_ctx **ctx) | |
54 | { | |
55 | struct lttng_ctx_field *field; | |
56 | ||
57 | field = lttng_append_context(ctx); | |
58 | if (!field) | |
59 | return -ENOMEM; | |
60 | if (lttng_find_context(*ctx, "cpu_id")) { | |
61 | lttng_remove_context_field(ctx, field); | |
62 | return -EEXIST; | |
63 | } | |
64 | field->event_field.name = "cpu_id"; | |
65 | field->event_field.type.atype = atype_integer; | |
218deb69 MD |
66 | field->event_field.type.u.integer.size = sizeof(int) * CHAR_BIT; |
67 | field->event_field.type.u.integer.alignment = lttng_alignof(int) * CHAR_BIT; | |
68 | field->event_field.type.u.integer.signedness = lttng_is_signed_type(int); | |
69 | field->event_field.type.u.integer.reverse_byte_order = 0; | |
70 | field->event_field.type.u.integer.base = 10; | |
71 | field->event_field.type.u.integer.encoding = lttng_encode_none; | |
c7ea8487 MD |
72 | field->get_size = cpu_id_get_size; |
73 | field->record = cpu_id_record; | |
74 | field->get_value = cpu_id_get_value; | |
75 | lttng_context_update(*ctx); | |
76 | return 0; | |
77 | } |