lib/trace.h

   1 /* Tracing macros
   2  *
   3  * Wraps tracepoint macros for different tracing systems to allow switching
   4  * between them at compile time.
   5  *
   6  * This should not be included directly by source files wishing to provide
   7  * tracepoints. Instead, write a header that defines LTTng tracepoints and
   8  * which includes this header, and include your new header in your source. USDT
   9  * probes do not need tracepoint definitions, but are less capable than LTTng
  10  * tracepoints.
  11  *
  12  * Copyright (C) 2020  NVIDIA Corporation
  13  * Quentin Young
  14  *
  15  * This program is free software; you can redistribute it and/or modify it
  16  * under the terms of the GNU General Public License as published by the Free
  17  * Software Foundation; either version 2 of the License, or (at your option)
  18  * any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful, but WITHOUT
  21  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  22  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  23  * more details.
  24  *
  25  * You should have received a copy of the GNU General Public License along
  26  * with this program; see the file COPYING; if not, write to the Free Software
  27  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  28  */
  29
  30 #ifndef _TRACE_H_
  31 #define _TRACE_H_
  32
  33 #ifdef HAVE_CONFIG_H
  34 #include "config.h"
  35 #endif /* HAVE_CONFIG_H */
  36
  37 /*
  38  * Provided here:
  39  * - frrtrace(n, provider, name, ...args...)
  40  * - frrtrace_enabled(provider, name)
  41  * - frrtracelog(level, msg, ...)
  42  *
  43  * Use frrtrace() to define tracepoints. n is the number of arguments; this is
  44  * needed because USDT probe definitions use DTRACE_PROBEn macros, so the
  45  * number of args must be passed in order to expand the correct macro.
  46  *
  47  * frrtrace_enabled() maps to tracepoint_enabled() under LTTng and is always
  48  * true when using USDT. In the future it could be mapped to USDT semaphores
  49  * but this is not implemented at present.
  50  *
  51  * frrtracelog() maps to tracelog() under LTTng and should only be used in zlog
  52  * core code, to propagate zlog messages to LTTng. It expands to nothing
  53  * otherwise.
  54  */
  55
  56 #if defined(HAVE_LTTNG)
  57
  58 #define frrtrace(nargs, provider, name, ...) \
  59         tracepoint(provider, name, ## __VA_ARGS__)
  60 #define frrtrace_enabled(...) tracepoint_enabled(__VA_ARGS__)
  61 #define frrtracelog(...) tracelog(__VA_ARGS__)
  62
  63 #elif defined(HAVE_USDT)
  64
  65 #include "sys/sdt.h"
  66
  67 #define frrtrace(nargs, provider, name, ...) \
  68         DTRACE_PROBE##nargs(provider, name, ## __VA_ARGS__)
  69 #define frrtrace_enabled(...) true
  70 #define frrtracelog(...)
  71
  72 #else
  73
  74 #define frrtrace(nargs, provider, name, ...) (void)0
  75 #define frrtrace_enabled(...) false
  76 #define frrtracelog(...) (void)0
  77
  78 #endif
  79
  80 #endif /* _TRACE_H_ */