Tor
0.4.9.0-alpha-dev
lib
trace
events.h
Go to the documentation of this file.
1
/* Copyright (c) 2017-2021, The Tor Project, Inc. */
2
/* See LICENSE for licensing information */
3
4
/**
5
* \file events.h
6
* \brief Header file for Tor tracing instrumentation definition.
7
**/
8
9
#ifndef TOR_LIB_TRACE_EVENTS_H
10
#define TOR_LIB_TRACE_EVENTS_H
11
12
#include "orconfig.h"
13
14
/*
15
* A tracepoint signature is defined as follow:
16
*
17
* tor_trace(<subsystem>, <event_name>, <args>...)
18
*
19
* If tracing is enabled, the tor_trace() macro is mapped to all possible
20
* instrumentations (defined below). Each instrumentation type MUST define a
21
* top level macro (TOR_TRACE_<type>) so it can be inserted into each
22
* tracepoint.
23
*
24
* In case no tracing is enabled (HAVE_TRACING), tracepoints are NOP and thus
25
* have no execution cost.
26
*
27
* Currently, three types of instrumentation are supported:
28
*
29
* log-debug: Every tracepoints is mapped to a log_debug() statement.
30
*
31
* User Statically-Defined Tracing (USDT): Probes that can be used with perf,
32
* dtrace, SystemTap, DTrace and BPF Compiler Collection (BCC).
33
*
34
* LTTng-UST: Probes for the LTTng Userspace Tracer. If USDT interface
35
* (sdt.h) is available, the USDT probes are also generated by LTTng thus
36
* enabling this instrumentation provides both probes.
37
*/
38
39
/** Helper to disambiguate these identifiers in the code base. They should
40
* only be used with tor_trace() like so:
41
*
42
* tor_trace(TR_SUBSYS(circuit), TR_EV(opened), ...);
43
*/
44
45
#define TR_SUBSYS(name) tor_ ## name
46
#define TR_EV(name) name
47
48
#ifdef HAVE_TRACING
49
50
#define tor_trace(subsystem, event_name, ...) \
51
do { \
52
TOR_TRACE_LOG_DEBUG(subsystem, event_name); \
53
TOR_TRACE_USDT(subsystem, event_name, ## __VA_ARGS__); \
54
TOR_TRACE_LTTNG(subsystem, event_name, ## __VA_ARGS__); \
55
} while (0)
56
57
/* This corresponds to the --enable-tracing-instrumentation-log-debug
58
* configure option which maps all tracepoints to a log_debug() statement. */
59
#include "
lib/trace/debug.h
"
60
61
/* This corresponds to the --enable-tracing-instrumentation-usdt configure
62
* option which will generate USDT probes for each tracepoints. */
63
#include "lib/trace/usdt/usdt.h"
64
65
/* This corresponds to the --enable-tracing-instrumentation-lttng configure
66
* option which will generate LTTng probes for each tracepoints. */
67
#include "
lib/trace/lttng/lttng.h
"
68
69
#else
/* !defined(HAVE_TRACING) */
70
71
/* Reaching this point, tracing is disabled thus we NOP every tracepoints
72
* declaration so we have no execution cost at runtime. */
73
#define tor_trace(subsystem, name, ...)
74
75
#endif
/* defined(HAVE_TRACING) */
76
77
#endif
/* !defined(TOR_LIB_TRACE_EVENTS_H) */
debug.h
Macros for debugging our event-trace support.
lttng.h
Header file for lttng.c.
Generated by
1.9.4