2 * (C) Copyright 2009-2011 -
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
5 * LTTng UST vtid context.
7 * Dual LGPL v2.1/GPL v2 license.
10 #include <sys/types.h>
12 #include <ust/lttng-events.h>
13 #include <ust/lttng-tracer.h>
14 #include <ust/ringbuffer-config.h>
20 #if defined(_syscall0)
21 _syscall0(pid_t
, gettid
)
22 #elif defined(__NR_gettid)
23 static inline pid_t
gettid(void)
25 return syscall(__NR_gettid
);
28 #warning "use pid as tid"
29 static inline pid_t
gettid(void)
36 * We cache the result to ensure we don't trigger a system call for
39 static __thread pid_t cached_vtid
;
42 size_t vtid_get_size(size_t offset
)
46 size
+= lib_ring_buffer_align(offset
, lttng_alignof(pid_t
));
47 size
+= sizeof(pid_t
);
52 void vtid_record(struct lttng_ctx_field
*field
,
53 struct lib_ring_buffer_ctx
*ctx
,
54 struct ltt_channel
*chan
)
56 if (unlikely(!cached_vtid
))
57 cached_vtid
= gettid();
58 lib_ring_buffer_align_ctx(ctx
, lttng_alignof(cached_vtid
));
59 chan
->ops
->event_write(ctx
, &cached_vtid
, sizeof(cached_vtid
));
62 int lttng_add_vtid_to_ctx(struct lttng_ctx
**ctx
)
64 struct lttng_ctx_field
*field
;
66 field
= lttng_append_context(ctx
);
69 if (lttng_find_context(*ctx
, "vtid")) {
70 lttng_remove_context_field(ctx
, field
);
73 field
->event_field
.name
= "vtid";
74 field
->event_field
.type
.atype
= atype_integer
;
75 field
->event_field
.type
.u
.basic
.integer
.size
= sizeof(pid_t
) * CHAR_BIT
;
76 field
->event_field
.type
.u
.basic
.integer
.alignment
= lttng_alignof(pid_t
) * CHAR_BIT
;
77 field
->event_field
.type
.u
.basic
.integer
.signedness
= lttng_is_signed_type(pid_t
);
78 field
->event_field
.type
.u
.basic
.integer
.reverse_byte_order
= 0;
79 field
->event_field
.type
.u
.basic
.integer
.base
= 10;
80 field
->event_field
.type
.u
.basic
.integer
.encoding
= lttng_encode_none
;
81 field
->get_size
= vtid_get_size
;
82 field
->record
= vtid_record
;