零拷贝的配置方法

参考：https://github.com/ros2/rmw_fastrtps#full-qos-configuration

问题

测试零拷贝时出现如下问题：

terminate called after throwing an instance of 'eprosima::fastcdr::exception::NotEnoughMemoryException'
  what():  Not enough memory in the buffer stream

堆栈如下：

对应的源码位置：

看堆栈崩溃原因是因为创建节点（rclcpp::Node）时，会发送node创建的消息，序列化时崩溃（具体是在序列化node的namespace，即”/“）

解决方法是在dds_profile.xml中增加如下配置:

<?xml version="1.0" encoding="UTF-8" ?>
<profiles xmlns="http://www.eprosima.com/XMLSchemas/fastRTPS_Profiles">
    <transport_descriptors>
        <transport_descriptor>
            <transport_id>CustomUDPTransport</transport_id>
            <type>UDPv4</type>
            <interfaceWhiteList>
                <address>192.168.1.2</address>
                <address>127.0.0.1</address>
            </interfaceWhiteList>
            <maxInitialPeersRange>10</maxInitialPeersRange>
            <maxMessageSize>65500</maxMessageSize>
            <sendBufferSize>1048576</sendBufferSize>
            <receiveBufferSize>1048576</receiveBufferSize>
        </transport_descriptor>
    </transport_descriptors>
    <participant profile_name="CustomUDPTransportParticipant" is_default_profile="true">
        <rtps>
            <useBuiltinTransports>true</useBuiltinTransports>
            <userTransports>
                <transport_id>CustomUDPTransport</transport_id>
            </userTransports>
        </rtps>
    </participant>
    <!-- 增加如下data_writer和data_reader配置解决上述问题 -->
    <data_writer profile_name="default publisher profile" is_default_profile="true">
      <qos>
        <publishMode>
          <kind>SYNCHRONOUS</kind>
        </publishMode>
        <data_sharing>
          <kind>AUTOMATIC</kind>
        </data_sharing>
      </qos>
      <historyMemoryPolicy>DYNAMIC</historyMemoryPolicy>
    </data_writer>
    <data_reader profile_name="default subscription profile" is_default_profile="true">
      <qos>
        <data_sharing>
          <kind>AUTOMATIC</kind>
        </data_sharing>
      </qos>
      <historyMemoryPolicy>DYNAMIC</historyMemoryPolicy>
    </data_reader>
</profiles>

1、设置环境变量：

export RMW_IMPLEMENTATION=rmw_fastrtps_cpp
export RMW_FASTRTPS_USE_QOS_FROM_XML=1  # 必须
export FASTRTPS_DEFAULT_PROFILES_FILE=/home/ubuntu/data/param/dds_profile.xml

/home/ubuntu/data/param/dds_profile.xml:

<?xml version="1.0" encoding="UTF-8"?>
<dds xmlns="http://www.eprosima.com/XMLSchemas/fastRTPS_Profiles">
    <profiles>
        <!-- Default publisher profile -->
        <publisher profile_name="default publisher profile" is_default_profile="true">
            <qos>
                <publishMode>
                    <kind>SYNCHRONOUS</kind>
                </publishMode>
                <data_sharing>
                    <kind>AUTOMATIC</kind>
                </data_sharing>
            </qos>
            <historyMemoryPolicy>PREALLOCATED_WITH_REALLOC</historyMemoryPolicy>
        </publisher>
        <!-- Default subscriber profile -->
        <subscriber profile_name="default subscriber profile" is_default_profile="true">
            <qos>
                <data_sharing>
                    <kind>AUTOMATIC</kind>
                </data_sharing>
            </qos>
            <historyMemoryPolicy>PREALLOCATED_WITH_REALLOC</historyMemoryPolicy>
        </subscriber>
        <!-- Publisher profile for topic helloworld -->
        <publisher profile_name="helloworld">
            <qos>
                <publishMode>
                    <kind>SYNCHRONOUS</kind>
                </publishMode>
                <data_sharing>
                    <kind>AUTOMATIC</kind>
                </data_sharing>
            </qos>
        </publisher>
        <!-- Request subscriber profile for services -->
        <subscriber profile_name="service">
            <qos>
                <data_sharing>
                    <kind>AUTOMATIC</kind>
                </data_sharing>
            </qos>
            <historyMemoryPolicy>PREALLOCATED_WITH_REALLOC</historyMemoryPolicy>
        </subscriber>
        <!-- Request publisher profile for clients -->
        <publisher profile_name="client">
            <qos>
                <publishMode>
                    <kind>ASYNCHRONOUS</kind>
                </publishMode>
                <data_sharing>
                    <kind>AUTOMATIC</kind>
                </data_sharing>
            </qos>
        </publisher>
        <!-- Request subscriber profile for server of service "add_two_ints" -->
        <subscriber profile_name="rq/add_two_intsRequest">
            <qos>
                <data_sharing>
                    <kind>AUTOMATIC</kind>
                </data_sharing>
            </qos>
            <historyMemoryPolicy>PREALLOCATED_WITH_REALLOC</historyMemoryPolicy>
        </subscriber>
        <!-- Reply subscriber profile for client of service "add_two_ints" -->
        <subscriber profile_name="rr/add_two_intsReply">
            <qos>
                <data_sharing>
                    <kind>AUTOMATIC</kind>
                </data_sharing>
            </qos>
            <historyMemoryPolicy>PREALLOCATED_WITH_REALLOC</historyMemoryPolicy>
        </subscriber>
    </profiles>
</dds>