[ros-users] Ros on Arm Hanging

Daniel Stonier d.stonier at gmail.com
Thu Jul 1 00:46:36 UTC 2010


Hi all,

We're trying to get ros running on an armv6 core here and hitting a
few issues. If anyone has any insight on how to go about tracking down
the issues that would be great.

Some general details about the problem:

It's an armv6 core running a custom gentoo with cturtle. The example
programs I have to test with are a simple client-server pair. The
client pings the server with a timestamped rpc service request, the
server too, timestamps and then sends a response. When the response is
received by the client, it outputs and terminates.

So it's pretty simple, no more than a few lines of code in server and
client (I've added the code below). End result though, the server
catches the request, at which point both client and server hang and
server cpu % goes through the roof. Since the code is simple, I'm
figuring it must be behind the scenes somewhere (maybe in the rosdep
library builds or system configuration?)  I'm not sure how to track
down the issue though - anyone have any ideas?

Cheers,
Daniel.

***************************** client.cpp *****************************

class LatencyClient {
public:
    LatencyClient() :
        client(node.serviceClient< rpc_latency::ping_pong >("rpc_latency"))
    {}
    /**
     * Latency benchmarking service request handler. This initiates
the request and waits
     * for the response. Handling is done in main().
     * @return bool - success or failure of the request.
     */
    bool ping_pong() {
        rpc_latency::ping_pong srv;
        TimeStamp send_stamp;
        TimeStamp final_stamp;

        srv.request.ping_time = static_cast<double>(send_stamp.stamp());
        if ( client.call(srv) ) {
            final_stamp.stamp();
            ROS_INFO("Send   Time : %lf", srv.response.pong_time -
srv.request.ping_time);
            ROS_INFO("Return Time : %lf",
static_cast<double>(final_stamp) - srv.response.pong_time);
            ROS_INFO("Round  Trip : %lf",
static_cast<double>(final_stamp - send_stamp) );
            return true;
        } else {
            ROS_ERROR("Failed to call service rpc_latency");
            return false;
        }
    }

private:
    ros::NodeHandle node;
    ros::ServiceClient client;
};

int main(int argc, char **argv) {
    ros::init(argc, argv, "rpc_latency_client");

    LatencyClient latency;
    latency.ping_pong();
    return 0;
}

***************************** server.cpp *****************************

class LatencyServer {
public:
    LatencyServer() :
        service (node.advertiseService("rpc_latency",
&LatencyServer::ping_pong, this))
    {}

    void spin() {
        ros::spin();
    }
    bool ping_pong(rpc_latency::ping_pong::Request  &request,
                   rpc_latency::ping_pong::Response &response ) {
        response.pong_time = timestamp.stamp();
        ROS_INFO("TimeStamp: %lf", static_cast<double>(timestamp) );
        return true;
    }

private:
    TimeStamp timestamp;
    ros::NodeHandle node;
    ros::ServiceServer service;
};

int main(int argc, char **argv) {
    ros::init(argc, argv, "rpc_latency_server");

    LatencyServer latency_server;
    latency_server.spin();
    return 0;
}



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