/*
* lttng-context-cpu-id.c
*
* LTTng UST CPU id context.
*
* Note: threads can be migrated at any point while executing the
* tracepoint probe. This means the CPU id field (and filter) is only
* statistical. For instance, even though a user might select a
* cpu_id==1 filter, there may be few events recorded into the channel
* appearing from other CPUs, due to migration.
*
* Copyright (C) 2009-2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; only
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define _GNU_SOURCE
#include <sys/types.h>
#include <unistd.h>
#include <lttng/ust-events.h>
#include <lttng/ust-tracer.h>
#include <lttng/ringbuffer-config.h>
#include "../libringbuffer/getcpu.h"
static
size_t cpu_id_get_size(struct lttng_ctx_field *field, size_t offset)
{
size_t size = 0;
size += lib_ring_buffer_align(offset, lttng_alignof(int));
size += sizeof(int);
return size;
}
static
void cpu_id_record(struct lttng_ctx_field *field,
struct lttng_ust_lib_ring_buffer_ctx *ctx,
struct lttng_channel *chan)
{
int cpu;
cpu = lttng_ust_get_cpu();
lib_ring_buffer_align_ctx(ctx, lttng_alignof(cpu));
chan->ops->event_write(ctx, &cpu, sizeof(cpu));
}
static
void cpu_id_get_value(struct lttng_ctx_field *field,
struct lttng_ctx_value *value)
{
int cpu;
cpu = lttng_ust_get_cpu();
value->u.s64 = cpu;
}
int lttng_add_cpu_id_to_ctx(struct lttng_ctx **ctx)
{
struct lttng_ctx_field *field;
field = lttng_append_context(ctx);
if (!field)
return -ENOMEM;
if (lttng_find_context(*ctx, "cpu_id")) {
lttng_remove_context_field(ctx, field);
return -EEXIST;
}
field->event_field.name = "cpu_id";
field->event_field.type.atype = atype_integer;
field->event_field.type.u.basic.integer.size = sizeof(int) * CHAR_BIT;
field->event_field.type.u.basic.integer.alignment = lttng_alignof(int) * CHAR_BIT;
field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(int);
field->event_field.type.u.basic.integer.reverse_byte_order = 0;
field->event_field.type.u.basic.integer.base = 10;
field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
field->get_size = cpu_id_get_size;
field->record = cpu_id_record;
field->get_value = cpu_id_get_value;
lttng_context_update(*ctx);
return 0;
}