Set CMakeLists to only use default rmw for benchmarks (#1427)

* Set CMakeLists to only use default rmw for benchmarks

Signed-off-by: Stephen Brawner <brawner@gmail.com>

* Add comment

Signed-off-by: Stephen Brawner <brawner@gmail.com>

rclcpp/test/benchmark/CMakeLists.txt

@@ -1,69 +1,15 @@
 find_package(performance_test_fixture REQUIRED)
 
-#
-# Add a rmw-specific performance benchmark test from performance_test_fixture
-#
-# :param NAME: the target name which will also be used as the test name
-# :type NAME: string
-# :param SOURCE: the benchmark test target's source file
-# :type SOURCE: string
-# :param AMENT_DEPENDS: the ament dependincies for the benchmark test target
-# :type list of strings
-# :param LIBRARIES: the additional libraries the target needs to be linked
-#    against
-# :type list of strings
-# :param TEST_OPTIONS: arguments to pass directly to add_performance_test
-# :type list of strings
-function(add_rclcpp_benchmark NAME SOURCE)
-  set(multiValueArgs AMENT_DEPENDS LIBRARIES TEST_OPTIONS)
-  cmake_parse_arguments(
-    RCLCPP_BENCHMARK
-    ""
-    ""
-    "${multiValueArgs}"
-    "${ARGN}")
-  if(RCLCPP_BENCHMARK_UNPARSED_ARGUMENTS)
-    message(
-      FATAL_ERROR
-      "Unrecognized arguments for 'add_rclcpp_benchmark'"
-      " (${RCLCPP_BENCHMARK_UNPARSED_ARGUMENTS})")
-    return()
-  endif()
-  find_package(${rmw_implementation} REQUIRED)
-  message(STATUS "Adding ${NAME} for '${rmw_implementation}'")
-  set(rmw_implementation_env_var RMW_IMPLEMENTATION=${rmw_implementation})
-
-  set(full_benchmark_name ${NAME}${target_suffix})
-  add_performance_test(
-    ${full_benchmark_name}
-    ${SOURCE}
-    ${RCLCPP_BENCHMARK_TEST_OPTIONS}
-    ENV ${rmw_implementation_env_var})
-  if(TARGET ${full_benchmark_name})
-    if(RCLCPP_BENCHMARK_AMENT_DEPENDS)
-      ament_target_dependencies(
-        ${full_benchmark_name}
-        ${RCLCPP_BENCHMARK_AMENT_DEPENDS})
-    endif()
-    target_link_libraries(
-      ${full_benchmark_name}
-      ${PROJECT_NAME}
-      ${RCLCPP_BENCHMARK_LIBRARIES})
-  endif()
-endfunction()
-
-# Add new benchmarks inside this macro
-macro(rclcpp_benchmarks)
-  add_rclcpp_benchmark(benchmark_init_shutdown benchmark_init_shutdown.cpp)
-
-  set(SKIP_TEST "")
-  if(${rmw_implementation} MATCHES "(.*)connext(.*)")
-    set(SKIP_TEST "SKIP_TEST")
-  endif()
-  add_rclcpp_benchmark(
-    benchmark_node
-    benchmark_node.cpp
-    TEST_OPTIONS ${SKIP_TEST})
-endmacro()
-
-call_for_each_rmw_implementation(rclcpp_benchmarks)
+# These benchmarks are only being created and run for the default RMW
+# implementation. We are looking to test the performance of the ROS 2 code, not
+# the underlying middleware.
+
+add_performance_test(benchmark_init_shutdown benchmark_init_shutdown.cpp)
+if(TARGET benchmark_init_shutdown)
+  target_link_libraries(benchmark_init_shutdown ${PROJECT_NAME})
+endif()
+
+add_performance_test(benchmark_node benchmark_node.cpp)
+if(TARGET benchmark_node)
+  target_link_libraries(benchmark_node ${PROJECT_NAME})
+endif()