Hi Vijay, A few questions then. Is it acceptable for messages to be dropped? I thought actionlib used reliable data transfer. In my actual program, I am depending on every message being sent, and I would rather not use delays and risk my robot still locking up. To give you some perspective, I am using the client to plan a path to a destination, and I am using the server to execute the motor controls to drive on a path it is given. Using a timeout would be fine (it's what I'm doing in my production code, actually). But with this new result, it seems I should now cancel the goal any time waitForResult times out because I don't know if the server is just taking a long time or if its message was dropped and it's actually finished. What I was planning on doing was letting the motion planner follow the path until it is in imminent danger of colliding with something, in which case I would cancel the goal. Unfortunately, I have a new problem now where I cannot even cancel the goal. After timing out, the client always thinks it's goal is active, and I am unable to cancel the goal. The output I am getting from the attached example is: --- snip --- *[ INFO] [1301694170.491982098]: Sending goal [ INFO] [1301694170.492052098]: Waiting for result... [ INFO] [1301694170.492138988]: Server is aborting goal. [ INFO] [1301694170.492193892]: After waiting for the result, the state is ABORTED [ INFO] [1301694170.492232340]: Sending goal [ INFO] [1301694170.492279138]: Waiting for result... [ INFO] [1301694170.492341676]: Server is aborting goal. [ INFO] [1301694170.492388975]: After waiting for the result, the state is ABORTED* [ INFO] [1301694170.492443452]: Sending goal [ INFO] [1301694170.492543467]: Server is aborting goal. [ INFO] [1301694170.492620163]: Waiting for result... [ INFO] [1301694171.492789064]: After waiting for the result, the state is ACTIVE [ INFO] [1301694171.492909135]: Timeout, cancelling the goal *[ INFO] [1301694171.492953475]: After cancelling, the state is ACTIVE* *[ INFO] [1301694171.492977808]: The server is not done. [ INFO] [1301694172.493114619]: The server is not done. [ INFO] [1301694173.493301543]: The server is not done. [ INFO] [1301694174.493476758]: The server is not done.* ^C --- snip --- (Normal behaviour is italicised. Unexpected behaviour is bold) Might this be another problem, or am I misusing SimpleActionClient? Thanks again, -Ryan On Fri, Apr 1, 2011 at 4:54 PM, Vijay Pradeep wrote: > Hi Ryan, > > Ok, I think we're actually getting somewhere..... > > > > When I move the called to spinner.start() to where you suggested, the > client gets stuck on its call to waitForServer as follows: > Totally my bad. What I meant for you to do was the following: > 1) Construct client & server > 2) Spin up threads > 3) waitForServer > 4) Start sending goals > > To do this, you'll have to move spinner.start() to where I suggested, and > also move client_.waitForServer() to the top of run(). Currently, the app > is trying to waitForServer without any spin threads running, which is > causing it to get stuck. Sorry about that. I'd also suggest trying to run > with 1 spinner instead of 4, and see if that helps. > > Thanks for the gdb thread info. It looks like all the threads we're > worried about are happily waiting for inputs in pthread conditions. This > makes it seem even more like a message was being dropped. > > Also, I finally got it to freeze on my side, *with* debug on. See output: > > Done. > [ INFO] [1301690082.884716841]: Hogging time or something > Current State: ABORTED > [DEBUG] [1301690082.884784275]: IN DELETER > [DEBUG] [1301690082.884838215]: About to erase CommStateMachine > [DEBUG] [1301690082.884891598]: Done erasing CommStateMachine > [DEBUG] [1301690082.884948750]: about to start initGoal() > [DEBUG] [1301690082.885037423]: The action server has received a new goal > request > [DEBUG] [1301690082.885152395]: A new goal has been recieved by the single > goal action server > [DEBUG] [1301690082.885263065]: Accepting a new goal > [DEBUG] [1301690082.885330292]: Accepting goal, id: > /test_client_server-281-1301690082.884983820, stamp: 1301690082.88 > Server called. Aborting goal. > [DEBUG] [1301690082.885555049]: Setting the current goal as aborted > [DEBUG] [1301690082.885618287]: Setting status to aborted on goal, id: > /test_client_server-281-1301690082.884983820, stamp: 1301690082.88 > [DEBUG] [1301690082.885675967]: Publishing result for goal with id: > /test_client_server-281-1301690082.884983820 and stamp: 1301690082.88 > [DEBUG] [1301690082.885743824]: Getting status over the wire. > [DEBUG] [1301690082.885956181]: Done with initGoal() > [DEBUG] [1301690082.887905041]: Getting status over the wire. > [DEBUG] [1301690082.888000669]: Trying to transition to ACTIVE > [DEBUG] [1301690082.888064094]: Transitioning CommState from > WAITING_FOR_GOAL_ACK to ACTIVE > [DEBUG] [1301690082.888130878]: Transitioning SimpleState from [PENDING] to > [ACTIVE] > Active. > [DEBUG] [1301690082.888203846]: Trying to transition to WAITING_FOR_RESULT > *[DEBUG] [1301690082.888262411]: Transitioning CommState from ACTIVE to > WAITING_FOR_RESULT* > [DEBUG] [1301690083.088191441]: Getting status over the wire. > [DEBUG] [1301690083.288523198]: Getting status over the wire. > [DEBUG] [1301690083.488836856]: Getting status over the wire. > [DEBUG] [1301690083.688115542]: Getting status over the wire. > [DEBUG] [1301690083.888460218]: Getting status over the wire. > [DEBUG] [1301690084.088794991]: Getting status over the wire. > [DEBUG] [1301690084.288137860]: Getting status over the wire. > [DEBUG] [1301690084.488456451]: Getting status over the wire. > [DEBUG] [1301690084.688742829]: Getting status over the wire. > [DEBUG] [1301690084.888085527]: Getting status over the wire. > [DEBUG] [1301690085.088418107]: Getting status over the wire. > > On the client side, the goal transitioned to WAITING_FOR_RESULT, which > means that the server successfully set the goal to a terminal state (in this > case, ABORTED). However, for some reason, the client never gets the result > message. With so many messages flying across so quickly, I guess one of the > result messages happens to get dropped. This also explains why adding a > sleep in the server callback stopped the freezing. The sleep significantly > slowed down the messaging rate, preventing the result message from being > dropped. > > It is definitely best practice to always add a timeout to waitForResult(). > I've updated the actionlib quickstart guideaccordingly. > > And, please let me know if any of the spinner tweaks I suggested make a > difference. > > Vijay > > > On Fri, Apr 1, 2011 at 1:07 PM, Ryan Miller wrote: > >> Hi Vijay, >> >> When I move the called to spinner.start() to where you suggested, the >> client gets stuck on its call to waitForServer as follows: >> >> --- snip --- >> $ rosrun chores chores >> [DEBUG] [1301684841.767308639]: Spinning up a thread for the >> SimpleActionClient >> [DEBUG] [1301684841.794376567]: goalConnectCallback: Adding >> [/test_client_server] to goalSubscribers >> [DEBUG] [1301684841.794470922]: Goal Subscribers (1 total) >> - /test_client_server >> [DEBUG] [1301684841.800129524]: cancelConnectCallback: Adding >> [/test_client_server] to cancelSubscribers >> [DEBUG] [1301684841.800199855]: cancel Subscribers (1 total) >> - /test_client_server >> [DEBUG] [1301684841.809336199]: isServerConnected: Didn't receive status >> yet, so not connected yet >> [DEBUG] [1301684841.809441030]: isServerConnected: Didn't receive status >> yet, so not connected yet >> [DEBUG] [1301684842.309665431]: isServerConnected: Didn't receive status >> yet, so not connected yet >> [DEBUG] [1301684842.810034890]: isServerConnected: Didn't receive status >> yet, so not connected yet >> ... >> [DEBUG] [1301684842.810034890]: isServerConnected: Didn't receive status >> yet, so not connected yet >> --- snip --- >> >> Also, it appears I have a heisenbug on my hands because when I turn on >> rosconsole debugging, the problem seemingly disappears, but when I keep it >> off, it crashes on almost every run. By the way, the single call to ROS_INFO >> I placed in the code is critical to making the program halt more often. >> Remove that, and you'll have more trouble getting the program to halt. >> >> Is there any other information that might help you replicate this problem? >> For now, I'll just throw some facts here about the computer I'm using. I am >> running Ubuntu 10.10 64-bit. I have replicated the problem on a relatively >> slow laptop and two pretty fast desktops. The specific package information >> for the version of ros-diamondback-common I am using is: >> >> --- snip --- >> $ dpkg -s ros-diamondback-common >> Package: ros-diamondback-common >> Status: install ok installed >> Priority: optional >> Section: unknown >> Installed-Size: 34224 >> Maintainer: Tully Foote tfoote@willowgarage.com >> Architecture: amd64 >> Version: 1.4.3-s1299027665~maverick >> Depends: ros-diamondback-common-msgs (= 1.4.0-s1299027564~maverick), >> ros-diamondback-ros (= 1.4.6-s1298587732~maverick), ros-diamondback-ros-comm >> (= 1.4.5-s1299027222~maverick), libc6, build-essential, cmake, python-yaml, >> subversion, uuid-dev, libcppunit-dev >> Description: common code for personal robots >> This stack contains tools built on top of ROS core which are commonly used >> throughout the ROS ecosystem. >> Wg-Rosdistro: diamondback >> --- snip --- >> >> Here is some information from gdb from when the program halts. I've >> printed a list of the running threads as well as the backtraces of a few of >> the ones in different functions. >> >> --- snip --- >> Current State: ABORTED >> Server called. Aborting goal. >> Active. >> ^C >> Program received signal SIGINT, Interrupt. >> pthread_cond_timedwait@@GLIBC_2.3.2 () at >> ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> 212 ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S: No >> such file or directory. >> in ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S >> (gdb) info thread >> 12 Thread 0x7fffecea2700 (LWP 9649) pthread_cond_timedwait@@GLIBC_2.3.2 >> () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> 11 Thread 0x7fffed6a3700 (LWP 9646) pthread_cond_timedwait@@GLIBC_2.3.2 >> () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> 10 Thread 0x7fffedea4700 (LWP 9640) pthread_cond_timedwait@@GLIBC_2.3.2 >> () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> 9 Thread 0x7fffee6a5700 (LWP 9639) pthread_cond_timedwait@@GLIBC_2.3.2 >> () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> 8 Thread 0x7fffeeea6700 (LWP 9638) pthread_cond_timedwait@@GLIBC_2.3.2 >> () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> 7 Thread 0x7fffef6a7700 (LWP 9637) pthread_cond_timedwait@@GLIBC_2.3.2 >> () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> 6 Thread 0x7fffefea8700 (LWP 9636) pthread_cond_timedwait@@GLIBC_2.3.2 >> () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> 5 Thread 0x7ffff06a9700 (LWP 9635) pthread_cond_timedwait@@GLIBC_2.3.2 >> () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> 4 Thread 0x7ffff0eaa700 (LWP 9630) pthread_cond_wait@@GLIBC_2.3.2 () at >> ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162 >> 3 Thread 0x7ffff16ab700 (LWP 9629) 0x00007ffff534e2c3 in select () at >> ../sysdeps/unix/syscall-template.S:82 >> 2 Thread 0x7ffff1eac700 (LWP 9628) 0x00007ffff5349203 in __poll >> (fds=, nfds=, timeout=100) at >> ../sysdeps/unix/sysv/linux/poll.c:87 >> * 1 Thread 0x7ffff7fcd760 (LWP 9609) pthread_cond_timedwait@@GLIBC_2.3.2 >> () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> (gdb) bt >> #0 pthread_cond_timedwait@@GLIBC_2.3.2 () at >> ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> #1 0x000000000044c698 in timed_wait > >> (this=0x7fffffffe110, m=..., wait_duration=) at >> /usr/include/boost/thread/pthread/condition_variable.hpp:110 >> #2 >> boost::condition_variable_any::timed_wait, >> boost::posix_time::milliseconds> (this=0x7fffffffe110, m=..., >> wait_duration=) >> at /usr/include/boost/thread/pthread/condition_variable.hpp:133 >> #3 0x000000000044d355 in >> actionlib::SimpleActionClient > >> >::waitForResult (this=0x7fffffffe040, timeout=...) >> at >> /opt/ros/diamondback/stacks/common/actionlib/include/actionlib/client/simple_action_client.h:567 >> #4 0x00000000004583f6 in ClientGuy::run (this=0x7fffffffe040) at >> /home/pesckal/prometheus/ros/chores/src/main.cpp:50 >> #5 0x000000000042d8d5 in main (argc=1, argv=) at >> /home/pesckal/prometheus/ros/chores/src/main.cpp:87 >> (gdb) thread 2 >> [Switching to thread 2 (Thread 0x7ffff1eac700 (LWP 9628))]#0 >> 0x00007ffff5349203 in __poll (fds=, nfds=> optimized out>, timeout=100) at ../sysdeps/unix/sysv/linux/poll.c:87 >> 87 ../sysdeps/unix/sysv/linux/poll.c: No such file or directory. >> in ../sysdeps/unix/sysv/linux/poll.c >> (gdb) bt >> #0 0x00007ffff5349203 in __poll (fds=, nfds=> optimized out>, timeout=100) at ../sysdeps/unix/sysv/linux/poll.c:87 >> #1 0x00007ffff78c169a in ros::PollSet::update (this=0x69c650, >> poll_timeout=100) >> at >> /tmp/buildd/ros-diamondback-ros-comm-1.4.5/debian/ros-diamondback-ros-comm/opt/ros/diamondback/stacks/ros_comm/clients/cpp/roscpp/src/libros/poll_set.cpp:202 >> #2 0x00007ffff7906778 in ros::PollManager::threadFunc (this=0x69c650) >> at >> /tmp/buildd/ros-diamondback-ros-comm-1.4.5/debian/ros-diamondback-ros-comm/opt/ros/diamondback/stacks/ros_comm/clients/cpp/roscpp/src/libros/poll_manager.cpp:95 >> #3 0x00007ffff6df5230 in thread_proxy () from >> /usr/lib/libboost_thread.so.1.42.0 >> #4 0x00007ffff55f9971 in start_thread (arg=) at >> pthread_create.c:304 >> #5 0x00007ffff535592d in clone () at >> ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 >> #6 0x0000000000000000 in ?? () >> (gdb) thread 3 >> [Switching to thread 3 (Thread 0x7ffff16ab700 (LWP 9629))]#0 >> 0x00007ffff534e2c3 in select () at ../sysdeps/unix/syscall-template.S:82 >> 82 ../sysdeps/unix/syscall-template.S: No such file or directory. >> in ../sysdeps/unix/syscall-template.S >> (gdb) bt >> #0 0x00007ffff534e2c3 in select () at >> ../sysdeps/unix/syscall-template.S:82 >> #1 0x00007ffff723313a in XmlRpc::XmlRpcDispatch::work (this=0x69ac18, >> timeout=) >> at >> /tmp/buildd/ros-diamondback-ros-comm-1.4.5/debian/ros-diamondback-ros-comm/opt/ros/diamondback/stacks/ros_comm/utilities/xmlrpcpp/src/XmlRpcDispatch.cpp:110 >> #2 0x00007ffff7903de9 in ros::XMLRPCManager::serverThreadFunc >> (this=0x69abc0) >> at >> /tmp/buildd/ros-diamondback-ros-comm-1.4.5/debian/ros-diamondback-ros-comm/opt/ros/diamondback/stacks/ros_comm/clients/cpp/roscpp/src/libros/xmlrpc_manager.cpp:256 >> #3 0x00007ffff6df5230 in thread_proxy () from >> /usr/lib/libboost_thread.so.1.42.0 >> #4 0x00007ffff55f9971 in start_thread (arg=) at >> pthread_create.c:304 >> #5 0x00007ffff535592d in clone () at >> ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 >> #6 0x0000000000000000 in ?? () >> (gdb) thread 4 >> [Switching to thread 4 (Thread 0x7ffff0eaa700 (LWP 9630))]#0 >> pthread_cond_wait@@GLIBC_2.3.2 () at >> ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162 >> 162 ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S: No such >> file or directory. >> in ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S >> (gdb) bt >> #0 pthread_cond_wait@@GLIBC_2.3.2 () at >> ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162 >> #1 0x00007ffff79603b3 in wait (this=) at >> /usr/include/boost/thread/pthread/condition_variable.hpp:20 >> #2 ros::ROSOutAppender::logThread (this=) >> at >> /tmp/buildd/ros-diamondback-ros-comm-1.4.5/debian/ros-diamondback-ros-comm/opt/ros/diamondback/stacks/ros_comm/clients/cpp/roscpp/src/libros/rosout_appender.cpp:135 >> #3 0x00007ffff6df5230 in thread_proxy () from >> /usr/lib/libboost_thread.so.1.42.0 >> #4 0x00007ffff55f9971 in start_thread (arg=) at >> pthread_create.c:304 >> #5 0x00007ffff535592d in clone () at >> ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 >> #6 0x0000000000000000 in ?? () >> (gdb) thread 5 >> [Switching to thread 5 (Thread 0x7ffff06a9700 (LWP 9635))]#0 >> pthread_cond_timedwait@@GLIBC_2.3.2 () at >> ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> 212 ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S: No >> such file or directory. >> in ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S >> (gdb) bt >> #0 pthread_cond_timedwait@@GLIBC_2.3.2 () at >> ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:212 >> #1 0x00007ffff796885d in bool >> boost::condition_variable::timed_wait> 1000000l> >(boost::unique_lock&, >> boost::date_time::subsecond_duration> 1000000l> const&) () from >> /opt/ros/diamondback/stacks/ros_comm/clients/cpp/roscpp/lib/libros.so >> #2 0x00007ffff7964e99 in ros::CallbackQueue::callAvailable >> (this=0x69c410, timeout=DWARF-2 expression error: DW_OP_reg operations must >> be used either alone or in conjuction with DW_OP_piece or DW_OP_bit_piece. >> ) >> at >> /tmp/buildd/ros-diamondback-ros-comm-1.4.5/debian/ros-diamondback-ros-comm/opt/ros/diamondback/stacks/ros_comm/clients/cpp/roscpp/src/libros/callback_queue.cpp:307 >> #3 0x00007ffff78f22e1 in ros::internalCallbackQueueThreadFunc () >> at >> /tmp/buildd/ros-diamondback-ros-comm-1.4.5/debian/ros-diamondback-ros-comm/opt/ros/diamondback/stacks/ros_comm/clients/cpp/roscpp/src/libros/init.cpp:265 >> #4 0x00007ffff6df5230 in thread_proxy () from >> /usr/lib/libboost_thread.so.1.42.0 >> #5 0x00007ffff55f9971 in start_thread (arg=) at >> pthread_create.c:304 >> #6 0x00007ffff535592d in clone () at >> ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 >> #7 0x0000000000000000 in ?? () >> (gdb) >> --- snip --- >> >> Also, I'm sorry to hear you had to create a new package to compile the >> program. As a sanity check, I also created a new package and copied over the >> cpp and action files, but this did not change the result I was having, as >> expected. (I've attached the package, for reference.) >> >> I really appreciate the help, thank you. >> >> -Ryan >> >> >> On Fri, Apr 1, 2011 at 2:03 PM, Vijay Pradeep >> wrote: >> > Hi Ryan, >> > >> > Here's one more thing to try. Turn on rosconsole debugging (See >> rosconole >> > configuration) >> > >> > You're going to want the following two lines in your rosonsole.config: >> > log4j.logger.ros.actionlib=DEBUG >> > log4j.logger.ros.chores=DEBUG >> > >> > >> > You'll get an output that looks like this: >> > [DEBUG] [1301680806.580203868]: Setting the current goal as aborted >> > [DEBUG] [1301680806.580254603]: Setting status to aborted on goal, id: >> > /test_client_server-1118-1301680806.579359151, stamp: 1301680806.58 >> > [DEBUG] [1301680806.580301868]: Publishing result for goal with id: >> > /test_client_server-1118-1301680806.579359151 and stamp: 1301680806.58 >> > [DEBUG] [1301680806.580439068]: Getting status over the wire. >> > [DEBUG] [1301680806.580509625]: Trying to transition to ACTIVE >> > [DEBUG] [1301680806.580553872]: Transitioning CommState from >> > WAITING_FOR_GOAL_ACK to ACTIVE >> > [DEBUG] [1301680806.580603042]: Transitioning SimpleState from [PENDING] >> to >> > [ACTIVE] >> > Active. >> > [DEBUG] [1301680806.580934461]: Trying to transition to >> WAITING_FOR_RESULT >> > [DEBUG] [1301680806.580991611]: Transitioning CommState from ACTIVE to >> > WAITING_FOR_RESULT >> > [DEBUG] [1301680806.581051376]: Trying to transition to DONE >> > [DEBUG] [1301680806.581108948]: Transitioning CommState from >> > WAITING_FOR_RESULT to DONE >> > [DEBUG] [1301680806.581164618]: Transitioning SimpleState from [ACTIVE] >> to >> > [DONE] >> > Done. >> > [ INFO] [1301680806.581243326]: Hogging time or something >> > Current State: ABORTED >> > [DEBUG] [1301680806.581302953]: IN DELETER >> > [DEBUG] [1301680806.581339010]: About to erase CommStateMachine >> > [DEBUG] [1301680806.581377433]: Done erasing CommStateMachine >> > [DEBUG] [1301680806.581414297]: about to start initGoal() >> > [DEBUG] [1301680806.581489440]: Done with initGoal() >> > [DEBUG] [1301680806.581544720]: The action server has received a new >> goal >> > request >> > [DEBUG] [1301680806.581638097]: A new goal has been recieved by the >> single >> > goal action server >> > [DEBUG] [1301680806.581705716]: Accepting a new goal >> > [DEBUG] [1301680806.581758609]: Accepting goal, id: >> > /test_client_server-1119-1301680806.581440270, stamp: 1301680806.58 >> > Server called. Aborting goal. >> > >> > Can send me the debug output for the last few cycles when your app >> freezes? >> > >> > Vijay >> > >> > On Fri, Apr 1, 2011 at 10:05 AM, Vijay Pradeep < >> vpradeep@willowgarage.com> >> > wrote: >> >> >> >> Hi Ryan, >> >> >> >> So I actually ran your original chores app overnight (~10 hours), and >> it >> >> still didn't freeze. >> >> >> >> Also, right now, I tried running your new chores app about 30 times >> (for >> >> about 5 seconds on each run), and it still hadn't frozen. I couldn't >> get >> >> the app to build using your CMakeLists and Makefile, so I rewrote them >> based >> >> on the standard "roscreate-pkg" versions of these files. I doubt this >> would >> >> affect the functionality. >> >> >> >> The fact that it freezes close to startup is interesting. My guess >> would >> >> be that it is having some sort of startup interaction with the >> AsyncSpinner. >> >> >> >> Instead of: >> >> int main(int argc, char** argv) { >> >> ros::init(argc, argv, "test_client_server"); >> >> >> >> ros::AsyncSpinner spinner(4); >> >> spinner.start(); >> >> >> >> ServerDude sd; >> >> >> >> ClientGuy client; >> >> client.run(); >> >> >> >> return 0; >> >> } >> >> >> >> Can you try: >> >> int main(int argc, char** argv) { >> >> ros::init(argc, argv, "test_client_server"); >> >> >> >> ros::AsyncSpinner spinner(4); >> >> >> >> ServerDude sd; >> >> >> >> ClientGuy client; >> >> spinner.start(); >> >> client.run(); >> >> >> >> return 0; >> >> } >> >> >> >> I would really like to get to the bottom of this, but it's hard to do >> much >> >> on my end if I can't actually get it to halt. >> >> >> >> Vijay >> >> >> >> On Fri, Apr 1, 2011 at 7:51 AM, Ryan Miller >> wrote: >> >>> >> >>> Hey Vijay, thanks for helping (and sorry for the double post; I >> >>> accidentally forgot to reply all, and I figure some people on the list >> >>> may be interested in the email). Yes, I did mean waitForResult, and I >> >>> am also using common-1.4.3 (diamondback too, if that's relevant). >> >>> Since you're having trouble duplicating the issue, I went back to >> >>> create an example closer to what I'm actually doing, and I managed to >> >>> get it to crash just as often. I've attached the project. >> >>> >> >>> If it doesn't crash after about 5 seconds, restart it. It seems if it >> >>> continues for more than 5 seconds, it is more likely to continue >> >>> running for much longer, but it usually halts within a second. >> >>> >> >>> Thanks a ton. >> >>> >> >>> -Ryan >> >>> >> >>> On Thu, Mar 31, 2011 at 11:00 PM, Vijay Pradeep >> >>> wrote: >> >>> > Hi Ryan, >> >>> > >> >>> > I'm sorry that you're having trouble getting actionlib to work. >> What >> >>> > version of the common stack do you have? >> >>> > >> >>> > Note that it is always possible for some of the ROS messages to be >> >>> > dropped. >> >>> > If the result message doesn't make it to the action client, then >> >>> > waitForResult is going to block forever. I'd suggest adding a >> timeout >> >>> > on >> >>> > waitForServer, and then preempting the goal if you end up waiting >> too >> >>> > long. >> >>> > >> >>> >> I made each callback print when >> >>> >> it was called, and I found that quite often, the program would >> block >> >>> >> forever when I called waitForServer. >> >>> > I'm guessing you meant "the program would block forever when I >> called >> >>> > waitForResult" >> >>> > >> >>> > I'm using common-1.4.3, and after running your example for ~10 >> minutes, >> >>> > it >> >>> > doesn't seem to freeze for me. I can rerun this test with the exact >> >>> > version >> >>> > of common that you're using. Is there anything you can do to make >> this >> >>> > minimal example freeze more often? Are there some strategic sleeps >> you >> >>> > could >> >>> > add to make it mimic your original app more closely? >> >>> > >> >>> > If you can get the chores app to freeze, you could try attaching gdb >> to >> >>> > the >> >>> > process and seeing where all the threads are (using the "info >> threads" >> >>> > command inside gdb). A bunch of them will be stuck on >> >>> > pthread_cond_timedwait calls, but I'd be curious if there's a thread >> >>> > stuck >> >>> > on a lock inside of actionlib. That would be indicative of a race >> >>> > condition >> >>> > in actionlib. >> >>> > >> >>> > Vijay >> >>> > >> >>> > On Thu, Mar 31, 2011 at 6:55 PM, Ryan Miller > > >> >>> > wrote: >> >>> >> >> >>> >> Because of a timing issue I can't quite pin down, actionlib >> >>> >> occasionally appears to exhibit a race condition. I found the >> problem >> >>> >> after adding callbacks to my client. I made each callback print >> when >> >>> >> it was called, and I found that quite often, the program would >> block >> >>> >> forever when I called waitForServer. The problem was that the >> client's >> >>> >> active callback was called but the server's execute method was >> never >> >>> >> called. >> >>> >> >> >>> >> I have reduced the problem into a simple ROS package with a single >> >>> >> executable that I have attached. After running the node for a >> while, I >> >>> >> finally noticed the same problem. It's last output before blocking >> >>> >> was: >> >>> >> >> >>> >> --- snip --- >> >>> >> Current State: ABORTED >> >>> >> Aborting. >> >>> >> Active. >> >>> >> Done. >> >>> >> Current State: ABORTED >> >>> >> Aborting. >> >>> >> Active. >> >>> >> --- snip --- >> >>> >> >> >>> >> In my actual code, the condition happens extremely frequently, but >> I >> >>> >> found I could mitigate the problem by sleeping for one millisecond >> >>> >> before returning from the server's execute method. (I should warn >> you >> >>> >> that in the attached example, the problem almost never occurs). >> >>> >> >> >>> >> Is this likely a bug, or might I doing something wrong? Any >> >>> >> suggestions would be appreciated. Thanks for the help. >> >>> >> >> >>> >> -Ryan >> >>> >> >> >>> >> _______________________________________________ >> >>> >> ros-users mailing list >> >>> >> ros-users@code.ros.org >> >>> >> https://code.ros.org/mailman/listinfo/ros-users >> >>> >> >> >>> > >> >>> > >> >>> > >> >>> > -- >> >>> > Vijay Pradeep >> >>> > Systems Engineer >> >>> > Willow Garage, Inc. >> >>> > vpradeep@willowgarage.com >> >>> > >> >>> > >> >> >> >> >> >> >> >> -- >> >> Vijay Pradeep >> >> Systems Engineer >> >> Willow Garage, Inc. >> >> vpradeep@willowgarage.com >> >> >> > >> > >> > >> > -- >> > Vijay Pradeep >> > Systems Engineer >> > Willow Garage, Inc. >> > vpradeep@willowgarage.com >> > >> > >> >> > > > -- > Vijay Pradeep > Systems Engineer > Willow Garage, Inc. > vpradeep@willowgarage.com > >