| 1 | /* |
| 2 | * SPDX-License-Identifier: LGPL-2.1-only |
| 3 | * |
| 4 | * Copyright (C) 2009-2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 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. |
| 13 | */ |
| 14 | |
| 15 | #define _LGPL_SOURCE |
| 16 | #include <stddef.h> |
| 17 | #include <sys/types.h> |
| 18 | #include <unistd.h> |
| 19 | #include <limits.h> |
| 20 | #include <lttng/ust-events.h> |
| 21 | #include <lttng/ust-tracer.h> |
| 22 | #include "../libringbuffer/getcpu.h" |
| 23 | #include <lttng/ringbuffer-context.h> |
| 24 | |
| 25 | #include "context-internal.h" |
| 26 | |
| 27 | static |
| 28 | size_t cpu_id_get_size(struct lttng_ust_ctx_field *field, size_t offset) |
| 29 | { |
| 30 | size_t size = 0; |
| 31 | |
| 32 | size += lttng_ust_lib_ring_buffer_align(offset, lttng_alignof(int)); |
| 33 | size += sizeof(int); |
| 34 | return size; |
| 35 | } |
| 36 | |
| 37 | static |
| 38 | void cpu_id_record(struct lttng_ust_ctx_field *field, |
| 39 | struct lttng_ust_lib_ring_buffer_ctx *ctx, |
| 40 | struct lttng_ust_channel_buffer *chan) |
| 41 | { |
| 42 | int cpu; |
| 43 | |
| 44 | cpu = lttng_ust_get_cpu(); |
| 45 | lttng_ust_lib_ring_buffer_align_ctx(ctx, lttng_alignof(cpu)); |
| 46 | chan->ops->event_write(ctx, &cpu, sizeof(cpu)); |
| 47 | } |
| 48 | |
| 49 | static |
| 50 | void cpu_id_get_value(struct lttng_ust_ctx_field *field, |
| 51 | struct lttng_ust_ctx_value *value) |
| 52 | { |
| 53 | value->u.s64 = lttng_ust_get_cpu(); |
| 54 | } |
| 55 | |
| 56 | int lttng_add_cpu_id_to_ctx(struct lttng_ust_ctx **ctx) |
| 57 | { |
| 58 | struct lttng_ust_ctx_field *field; |
| 59 | struct lttng_ust_type_common *type; |
| 60 | int ret; |
| 61 | |
| 62 | type = lttng_ust_create_type_integer(sizeof(int) * CHAR_BIT, |
| 63 | lttng_alignof(int) * CHAR_BIT, |
| 64 | lttng_ust_is_signed_type(int), |
| 65 | BYTE_ORDER, 10); |
| 66 | if (!type) |
| 67 | return -ENOMEM; |
| 68 | field = lttng_append_context(ctx); |
| 69 | if (!field) { |
| 70 | ret = -ENOMEM; |
| 71 | goto error_context; |
| 72 | } |
| 73 | if (lttng_find_context(*ctx, "cpu_id")) { |
| 74 | ret = -EEXIST; |
| 75 | goto error_find_context; |
| 76 | } |
| 77 | field->event_field->name = strdup("cpu_id"); |
| 78 | if (!field->event_field->name) { |
| 79 | ret = -ENOMEM; |
| 80 | goto error_name; |
| 81 | } |
| 82 | field->event_field->type = type; |
| 83 | field->get_size = cpu_id_get_size; |
| 84 | field->record = cpu_id_record; |
| 85 | field->get_value = cpu_id_get_value; |
| 86 | lttng_context_update(*ctx); |
| 87 | return 0; |
| 88 | |
| 89 | error_name: |
| 90 | error_find_context: |
| 91 | lttng_remove_context_field(ctx, field); |
| 92 | error_context: |
| 93 | lttng_ust_destroy_type(type); |
| 94 | return ret; |
| 95 | } |