subscribe callback function sometimes block for a long time

[RainingJoe]

trafficstars

Bug report

Required Info:

• Operating System:
  • Ubuntu 22.04 (docker)
• Installation type:
  • binaries
• DDS implementation:
  • Fast-RTPS
• Client library (if applicable):
  • rclcpp

Steps to reproduce issue

#include "rclcpp/rclcpp.hpp"
#include <ctime>
#include <sensor_msgs/msg/point_cloud2.hpp>
#include <functional>
#include <memory>
#include <chrono>

double last_front_tstamp = 0.0;
double last_rear_tstamp = 0.0;
double last_left_tstamp = 0.0;
double last_right_tstamp = 0.0;

long getCurrentTime()
{
        std::chrono::milliseconds ms = std::chrono::duration_cast< std::chrono::milliseconds >(
        std::chrono::system_clock::now().time_since_epoch());
        return ms.count();
}

using namespace std;

class DemoSubscriber : public rclcpp::Node
{
public:
    explicit DemoSubscriber(const string& name)
        : Node(name)

    {
        /*sub_pcloud_center_ = this->create_subscription<sensor_msgs::msg::PointCloud2>(
            "/sensor/lidar_center/pcloud_raw",
            1,
            [this](sensor_msgs::msg::PointCloud2::SharedPtr msg) {
                cout << "Center time interval: " << getCurrentTime()-last_center_tstamp << endl;
                last_center_tstamp = getCurrentTime();
            }
        );*/
        sub_pcloud_front_ = this->create_subscription<sensor_msgs::msg::PointCloud2>(
            "/sensor/rslidar_front/pcloud_distortion",
            10,
            [this](sensor_msgs::msg::PointCloud2::SharedPtr msg) {
                int diff = getCurrentTime()-last_front_tstamp;
                if (diff > 300 )
                  cout << "front time interval: " << diff << endl;
                last_front_tstamp = getCurrentTime();
            }
        );
        sub_pcloud_rear_ = this->create_subscription<sensor_msgs::msg::PointCloud2>(
            "/sensor/rslidar_rear/pcloud_distortion",
            10,
            [this](sensor_msgs::msg::PointCloud2::SharedPtr msg) {
                int diff = getCurrentTime()-last_rear_tstamp;
                if (diff > 300 )
                  cout << "rear time interval: " << diff << endl;
                last_rear_tstamp = getCurrentTime();
            }
        );
        sub_pcloud_left_ = this->create_subscription<sensor_msgs::msg::PointCloud2>(
            "/sensor/rslidar_left/pcloud_distortion",
            10,
            [this](sensor_msgs::msg::PointCloud2::SharedPtr msg) {
                int diff = getCurrentTime()-last_left_tstamp;
                if (diff > 300)
                  cout << "left time interval: " << diff << endl;
                last_left_tstamp = getCurrentTime();
            }
        );
        sub_pcloud_right_ = this->create_subscription<sensor_msgs::msg::PointCloud2>(
            "/sensor/rslidar_right/pcloud_distortion",
            10,
            [this](sensor_msgs::msg::PointCloud2::SharedPtr msg) {
                int diff = getCurrentTime()-last_right_tstamp;
                if (diff > 300)
                  cout << "right time interval: " << diff << endl;
                last_right_tstamp = getCurrentTime();
            }
        );
    }

private:
    rclcpp::Subscription<sensor_msgs::msg::PointCloud2>::SharedPtr sub_pcloud_center_;
    rclcpp::Subscription<sensor_msgs::msg::PointCloud2>::SharedPtr sub_pcloud_front_;
    rclcpp::Subscription<sensor_msgs::msg::PointCloud2>::SharedPtr sub_pcloud_rear_;
    rclcpp::Subscription<sensor_msgs::msg::PointCloud2>::SharedPtr sub_pcloud_right_;
    rclcpp::Subscription<sensor_msgs::msg::PointCloud2>::SharedPtr sub_pcloud_left_;
};

int main(int argc, char** argv)
{
    rclcpp::init(argc, argv);
    rclcpp::spin(make_shared<DemoSubscriber>("subscriber_node"));
    rclcpp::shutdown();

    return 0;
}

Expected behavior

There should no print.

Actual behavior

#### Additional information Four lidar topic steady ~ 10Hz ----

[fujitatomoya]

@RainingJoe thanks for creating issue. I got some questions,

• What platform do you use and reproduce this issue? (not docker, but host system CPU and platform information would be appreciated)
• system clock has never been changed during the test? e.g) ntp system time adjustment. i would use steady clock for this kind of test.
• Can you try MultiThreadedExecutor to see if the problem can be solved?