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Function execution is slow in callbacks. Why?

asked 2019-03-27 12:24:28 -0500

JeyP4 gravatar image

updated 2019-03-27 14:46:27 -0500

Hi My (Heavy) Image processing functionis slow in the subscriber callback. But if I run the same function outside ROS in release mode it is fast. (10X fast)

Why I want to put the image processing function in callback? Because I want to process received image as soon it arrives.

Any comments! My code looks like:

class storedData {
    cv::Mat inIm = cv::Mat::zeros(376, 672, CV_8UC3);
    cv::Mat outIm = cv::Mat::zeros(376, 672, CV_8UC3);

    void depthCallback(const sensor_msgs::CompressedImageConstPtr& msgDepth)
        tic2 = ros::Time::now();

        imProcess(inIm, outIm);         // Heavy Image Processing

        imPTime = ros::Time::now().toSec() - tic2.toSec();

        std::cout<<"Im process time= "<<imPTime<<std::endl;

        cv::imshow("view", outIm);
      catch (cv_bridge::Exception& e)
            ROS_ERROR("Could not convert the depth!");
int main(int argc, char **argv)
  ros::init(argc, argv, "PredictiveDisplay");
  ros::NodeHandle nh;
  storedData obj;
  cv::namedWindow("view", 0);

  ros::Subscriber subDepth = nh.subscribe("/depth/depth_registered/compressed", 2, &storedData::depthCallback, &obj);

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If you could add your instrumentation to the example it would be helpful with an example of it running fast inside the callback but slow outside the callback we'd be able to help you. Without being able to reproduce it all we can do is guess at things.

tfoote gravatar image tfoote  ( 2019-03-27 15:35:04 -0500 )edit

First thing I would try would be setting ROS_BUILD_TYPE to Release in your CMakeLists.txt. Also clean build the package. See the linked question for options.

You can read more about it here: question regarding a similar problem: catkin-compiled-code-runs-3x-slower

Reamees gravatar image Reamees  ( 2019-03-28 02:46:18 -0500 )edit

@gvdhoorn Thanks for your comment.

What does simple catkin_make do? It builds in debug or release mode?

JeyP4 gravatar image JeyP4  ( 2019-03-29 05:24:28 -0500 )edit

It's not Catkin that decides this, it's CMake.

If you don't configure any CMAKE_BUILD_TYPE, CMake will use None, which sets no flags at all.

gvdhoorn gravatar image gvdhoorn  ( 2019-03-29 07:48:09 -0500 )edit

Thanks @gvdhoorn.

catkin_make  -DCMAKE_BUILD_TYPE=RelWithDebInfo

magically worked for me. I can accept this as an answer, if you can convert it to answer.

JeyP4 gravatar image JeyP4  ( 2019-03-29 12:22:22 -0500 )edit

converted to an answer. Yes, it's a little surprising, the default build has no optimizations, but actually also does not have debug info either. It's really the default that you never really want.

tfoote gravatar image tfoote  ( 2019-03-29 15:54:38 -0500 )edit

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answered 2019-03-28 04:48:22 -0500

gvdhoorn gravatar image

updated 2019-03-28 04:48:30 -0500

First thing I would try would be setting ROS_BUILD_TYPE to Release in your CMakeLists.txt. [..] You can read more about it here:

Please don't refer to rosbuild pages. They're only kept for archival purposes.

ROS_BUILD_TYPE is not used in Catkin packages. Use CMAKE_BUILD_TYPE instead.

And don't set it in your CMakeLists.txt, but pass it as an argument to your catkin_make invocation (as: -DCMAKE_BUILD_TYPE=Release (or probably better: -DCMAKE_BUILD_TYPE=RelWithDebInfo)).

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Asked: 2019-03-27 12:24:28 -0500

Seen: 296 times

Last updated: Mar 27 '19