Hi there, I ran the program with the valgrind and found nothing fishy. Moreover it turned out that the decay in publishing rate only happens when there is a subscriber such as e.g. image_view subscribed to the topic. What I then tried next was to subscribe to the output topic with 3 "rostopic hz /image_topic_2" commands only - see also an attached rxgraph plot. This resulted in every subscription having less and less publishing rate (~ 30, 25 and 26 Hz respectively). Once again I ran this on one machine and over the loopback. The program publishing images is now also in tum-ros-pkg repo: http://tum-ros-pkg.svn.sourceforge.net/viewvc/tum-ros-pkg/perception/image_algos/utils/openCV_to_ros.cpp?revision=432&view=markup if someone wants to give it a try. Could the decay in publishing rate be attributed to the way ROS's subscribe mechanism handles the copying of data? cheers, D. On Fri, Apr 16, 2010 at 9:47 PM, Josh Faust wrote: > Whoops, should've looked at the attached source.  In general a profiler is > going to tell you what's taking time far better than we will. > > Josh > > On Fri, Apr 16, 2010 at 12:33 PM, Dejan Pangercic > wrote: >> >> Hi Josh, >> >> I did not do profiling yet. However, since I read the image only once >> when I start the program and then publish it from the memory, it can >> not be harddrive. >> D. >> >> On Fri, Apr 16, 2010 at 9:00 PM, Josh Faust >> wrote: >> > Have you tried profiling it to see where the time is being spent, and >> > where >> > the bottleneck is?  1.8MB * 30 = 54MB/sec, which could actually be >> > harddrive-limited depending on the drive you're reading from. >> > >> > Josh >> > >> > On Fri, Apr 16, 2010 at 11:26 AM, Dejan Pangercic >> > wrote: >> >> >> >> Hi there, >> >> >> >> I using an attached program to read an image from a disk and to then >> >> continously publish it on an image topic at 30 fps. On _one_ machine >> >> over loopback. When I tried it with a 1608x1236+0+0 color image >> >> (1.8MB) and then used rostopic hz to display the publishing rate of >> >> topic, >> >> the most that I got was around 12, 13 Hz. >> >> Any idea what would cause such a low performance? At what rates and >> >> sizes do you folks usually send images around? >> >> >> >> thx and cheers, D. >> >> >> >> -- >> >> MSc. Dejan Pangercic >> >> PhD Student/Researcher >> >> Computer Science IX >> >> Technische Universität München >> >> Telephone: +49 (89) 289-17780 >> >> E-Mail: dejan.pangercic@in.tum.de >> >> WWW: http://ias.cs.tum.edu/people/pangercic >> >> >> >> _______________________________________________ >> >> ros-users mailing list >> >> ros-users@code.ros.org >> >> https://code.ros.org/mailman/listinfo/ros-users >> >> >> > >> > >> > _______________________________________________ >> > ros-users mailing list >> > ros-users@code.ros.org >> > https://code.ros.org/mailman/listinfo/ros-users >> > >> > >> >> >> >> -- >> MSc. Dejan Pangercic >> PhD Student/Researcher >> Computer Science IX >> Technische Universität München >> Telephone: +49 (89) 289-17780 >> E-Mail: dejan.pangercic@in.tum.de >> WWW: http://ias.cs.tum.edu/people/pangercic >> _______________________________________________ >> ros-users mailing list >> ros-users@code.ros.org >> https://code.ros.org/mailman/listinfo/ros-users > > > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users > > -- MSc. Dejan Pangercic PhD Student/Researcher Computer Science IX Technische Universität München Telephone: +49 (89) 289-17780 E-Mail: dejan.pangercic@in.tum.de WWW: http://ias.cs.tum.edu/people/pangercic -- MSc. Dejan Pangercic PhD Student/Researcher Computer Science IX Technische Universität München Telephone: +49 (89) 289-17780 E-Mail: dejan.pangercic@in.tum.de WWW: http://ias.cs.tum.edu/people/pangercic