WIP: backport message flow tracing

src/CMakeLists.txt

@@ -37,6 +37,18 @@ endif()
 if(ENABLE_DEADLINE_MISSED)
   set(DDS_HAS_DEADLINE_MISSED "1")
 endif()
+
+find_package(PkgConfig)
+if(PkgConfig_FOUND)
+  pkg_check_modules(LTTNG lttng-ust)
+  if(LTTNG_FOUND)
+    message(STATUS "Building with LTTng instrumentation support")
+    set(DDS_HAS_LTTNG_TRACING "1")
+  else()
+    message(FATAL_ERROR "CYCLONE_ENABLE_TRACING requires lttng-ust")
+  endif()
+endif()
+
 configure_file(features.h.in "${CMAKE_CURRENT_BINARY_DIR}/core/include/dds/features.h")
 
 add_definitions(-DDDSI_INCLUDE_NETWORK_PARTITIONS -DDDSI_INCLUDE_SSM)

src/core/ddsc/CMakeLists.txt

@@ -42,6 +42,10 @@ PREPEND(srcs_ddsc "${CMAKE_CURRENT_LIST_DIR}/src"
     dds_sertopic_builtintopic.c
 )
 
+if (DDS_HAS_LTTNG_TRACING)
+  list(APPEND srcs_ddsc "${CMAKE_CURRENT_LIST_DIR}/src/tracing_lttng.c")
+endif()
+
 PREPEND(hdrs_public_ddsc "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include/dds>$<INSTALL_INTERFACE:include/dds>"
     dds.h
     ddsc/dds_public_error.h
@@ -81,6 +85,7 @@ PREPEND(hdrs_private_ddsc "${CMAKE_CURRENT_LIST_DIR}/src"
     dds__whc_builtintopic.h
     dds__serdata_builtintopic.h
     dds__get_status.h
+    tracing_lttng.h
 )
 
 generate_export_header(
@@ -108,6 +113,10 @@ target_include_directories(ddsc
     INTERFACE
         $<INSTALL_INTERFACE:include>)
 
+if (DDS_HAS_LTTNG_TRACING)
+  target_link_libraries(ddsc PRIVATE ${LTTNG_LIBRARIES})
+endif()
+
 install(
   DIRECTORY
       "${CMAKE_CURRENT_LIST_DIR}/include/"

src/core/ddsc/src/dds_read.c

@@ -20,6 +20,7 @@
 #include "dds/ddsi/q_entity.h"
 #include "dds/ddsi/ddsi_domaingv.h"
 #include "dds/ddsi/ddsi_sertopic.h"
+#include "tracing_lttng.h"
 
 /*
   dds_read_impl: Core read/take function. Usually maxs is size of buf and si
@@ -128,6 +129,7 @@ static dds_return_t dds_read_impl (bool take, dds_entity_t reader_or_condition,
   }
   dds_entity_unpin (entity);
   thread_state_asleep (ts1);
+  TRACEPOINT(read, (const void *)rd, (const void *)*buf);
   return ret;
 
 #undef NC_CLEAR_LOAN_OUT

src/core/ddsc/src/dds_reader.c

@@ -33,6 +33,7 @@
 #include "dds/ddsi/ddsi_entity_index.h"
 #include "dds/ddsi/ddsi_security_omg.h"
 #include "dds/ddsi/ddsi_statistics.h"
+#include "tracing_lttng.h"
 
 DECL_ENTITY_LOCK_UNLOCK (extern inline, dds_reader)
 
@@ -547,6 +548,11 @@ static dds_entity_t dds_create_reader_int (dds_entity_t participant_or_subscribe
   dds_topic_allow_set_qos (tp);
   dds_topic_unpin (tp);
   dds_subscriber_unlock (sub);
+
+  dds_guid_t guid;
+  (void)dds_get_guid(reader, &guid);
+  TRACEPOINT(create_reader, (const void *)rd, rd->m_topic->m_ktopic->name, guid.v);
+
   return reader;
 
 #ifdef DDSI_INCLUDE_SECURITY

src/core/ddsc/src/dds_write.c

@@ -26,6 +26,7 @@
 #include "dds/ddsi/q_radmin.h"
 #include "dds/ddsi/ddsi_domaingv.h"
 #include "dds/ddsi/ddsi_deliver_locally.h"
+#include "tracing_lttng.h"
 
 dds_return_t dds_write (dds_entity_t writer, const void *data)
 {
@@ -168,6 +169,8 @@ dds_return_t dds_write_impl (dds_writer *wr, const void * data, dds_time_t tstam
   if (data == NULL)
     return DDS_RETCODE_BAD_PARAMETER;
 
+  TRACEPOINT(write, (const void *)wr, (const char *)data, tstamp);
+
   /* Check for topic filter */
   if (wr->m_topic->filter_fn && !writekey)
     if (! wr->m_topic->filter_fn (data, wr->m_topic->filter_ctx))

src/core/ddsc/src/dds_writer.c

@@ -32,6 +32,7 @@
 #include "dds__whc.h"
 #include "dds__statistics.h"
 #include "dds/ddsi/ddsi_statistics.h"
+#include "tracing_lttng.h"
 
 DECL_ENTITY_LOCK_UNLOCK (extern inline, dds_writer)
 
@@ -395,6 +396,11 @@ dds_entity_t dds_create_writer (dds_entity_t participant_or_publisher, dds_entit
   dds_topic_allow_set_qos (tp);
   dds_topic_unpin (tp);
   dds_publisher_unlock (pub);
+
+  dds_guid_t guid;
+  (void)dds_get_guid(writer, &guid);
+  TRACEPOINT(create_writer, (const void *)wr, wr->m_topic->m_ktopic->name, guid.v);
+
   return writer;
 
 #ifdef DDSI_INCLUDE_SECURITY

src/core/ddsc/src/tracing_lttng.c

@@ -0,0 +1,16 @@
+/*
+ * Copyright(c) 2021 Christophe Bedard
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+ * v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+
+#define TRACEPOINT_CREATE_PROBES
+
+#define TRACEPOINT_DEFINE
+#include "tracing_lttng.h"

src/core/ddsc/src/tracing_lttng.h

@@ -0,0 +1,110 @@
+/*
+ * Copyright(c) 2021 Christophe Bedard
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+ * v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+
+// Provide fake header guard for cpplint
+#undef _DDS_LTTNG_H_
+#ifndef _DDS_LTTNG_H_
+#define _DDS_LTTNG_H_
+
+#include "dds/features.h"
+
+#undef TRACEPOINT_PROVIDER
+#define TRACEPOINT_PROVIDER dds
+
+#define TRACEPOINT(event_name, ...) \
+  tracepoint(TRACEPOINT_PROVIDER, event_name, __VA_ARGS__)
+
+#undef TRACEPOINT_INCLUDE
+#define TRACEPOINT_INCLUDE "tracing_lttng.h"
+
+#if !defined(__DDS_LTTNG_H_) || defined(TRACEPOINT_HEADER_MULTI_READ)
+#define __DDS_LTTNG_H_
+
+#include <lttng/tracepoint.h>
+
+#ifndef LTTNG_UST_HAVE_SDT_INTEGRATION
+#  ifdef _MSC_VER
+#    pragma message ("lttng-ust has not been configured & built with SDT integration (--with-sdt)")
+#  else
+#    warning lttng-ust has not been configured & built with SDT integration (--with-sdt)
+#  endif
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#define DDS_GID_STORAGE_SIZE 16u
+
+TRACEPOINT_EVENT(
+  TRACEPOINT_PROVIDER,
+  create_writer,
+  TP_ARGS(
+    const void *, writer_arg,
+    char *, topic_name_arg,
+    const uint8_t *, gid_arg
+  ),
+  TP_FIELDS(
+    ctf_integer_hex(const void *, writer, writer_arg)
+    ctf_string(topic_name, topic_name_arg)
+    ctf_array(uint8_t, gid, gid_arg, DDS_GID_STORAGE_SIZE)
+  )
+)
+
+TRACEPOINT_EVENT(
+  TRACEPOINT_PROVIDER,
+  create_reader,
+  TP_ARGS(
+    const void *, reader_arg,
+    char *, topic_name_arg,
+    const uint8_t *, gid_arg
+  ),
+  TP_FIELDS(
+    ctf_integer_hex(const void *, reader, reader_arg)
+    ctf_string(topic_name, topic_name_arg)
+    ctf_array(uint8_t, gid, gid_arg, DDS_GID_STORAGE_SIZE)
+  )
+)
+
+TRACEPOINT_EVENT(
+  TRACEPOINT_PROVIDER,
+  write,
+  TP_ARGS(
+    const void *, writer_arg,
+    const void *, data_arg,
+    int64_t, timestamp_arg
+  ),
+  TP_FIELDS(
+    ctf_integer_hex(const void *, writer, writer_arg)
+    ctf_integer_hex(const void *, data, data_arg)
+    ctf_integer(int64_t, timestamp, timestamp_arg)
+  )
+)
+
+TRACEPOINT_EVENT(
+  TRACEPOINT_PROVIDER,
+  read,
+  TP_ARGS(
+    const void *, reader_arg,
+    const void *, buffer_arg
+  ),
+  TP_FIELDS(
+    ctf_integer_hex(const void *, reader, reader_arg)
+    ctf_integer_hex(const void *, buffer, buffer_arg)
+  )
+)
+
+#endif  // __DDS_LTTNG_H_
+
+#include <lttng/tracepoint-event.h>
+
+#endif  // _DDS_LTTNG_H_
+

src/ddsrt/src/threads/posix/threads.c

@@ -129,7 +129,7 @@ ddsrt_thread_setname(const char *__restrict name)
      name exceeds the limit, so silently truncate. */
   char buf[MAXTHREADNAMESIZE + 1] = "";
   (void)ddsrt_strlcpy(buf, name, sizeof(buf));
-  (void)pthread_setname_np(pthread_self(), name);
+  (void)pthread_setname_np(pthread_self(), buf);
 #elif defined(__APPLE__)
   (void)pthread_setname_np(name);
 #elif defined(__FreeBSD__)

src/features.h.in

@@ -21,4 +21,7 @@
 /* Whether or not support for generating "deadline missed" events is included */
 #cmakedefine DDS_HAS_DEADLINE_MISSED @DDS_HAS_DEADLINE_MISSED@
 
+/* Whether or not support for LTTng tracing instrumentation is included */
+#cmakedefine DDS_HAS_LTTNG_TRACING @DDS_HAS_LTTNG_TRACING@
+
 #endif