# "Run to completion" not working with message passing blocks **URL:** \ **Category:** GNU Radio\ **Created:** [April 29, 2014, 3:35pm UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759 "2014-04-29T15:35:32Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Post date:** [April 29, 2014, 3:35pm UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/1 "2014-04-29T15:35:32Z")
Hi all, I want to use message passing blocks for operations where strict synchronization is not necessary. However in flowgraphs using message passing with “Run to completion” option turned on the program doesn’t exit on last processed sample. Is this a bug? I want to use message passing in my programs (mainly in [https://github.com/Jakotako/gr-gsm](https://github.com/Jakotako/gr-gsm)) but completion after processing of all input data is also very important for me. – Piotr K. ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [April 29, 2014, 4:56pm UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/2 "2014-04-29T16:56:31Z")
On Tue, Apr 29, 2014 at 9:33 AM, Perper [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > – > Piotr K. Yes, this is a known issue and we are working on it. Tom ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [February 16, 2015, 5:35pm UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/3 "2015-02-16T17:35:37Z")
On Sat, Feb 14, 2015 at 3:34 PM, Piotr K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > Yes, this is a known issue and we are working on it. > > I’m working on a simple gsm network monitor application based on gr-gsm > > Piotr K. The fix for this was pushed a couple of weeks ago and will make it in the 3.7.7 release. We’re looking to see any side effects and might be able to back-port it for the next 3.7.6 maint release. Commit here: > Tom ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [March 25, 2015, 11:14am UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/4 "2015-03-25T11:14:13Z")
W dniu 16.02.2015 o 17:29, Tom R. pisze: > ``` > > synchronization is not necessary. However in flowgraphs > > -- > In GNU Radio 3.7.6 this is still an issue. It's quite serious because > > ``` > > The fix for this was pushed a couple of weeks ago and will make it in > the 3.7.7 release. We’re looking to see any side effects and might be > able to back-port it for the next 3.7.6 maint release. Commit here: > > Tom I’ve tied gnuradio compiled with and without this commit. I didn’t observe difference - run to completion doesn’t seem to work with message passing. I’ve attached the gnuradio-companion flowgraph that I’ve used for the test. Question to the list: does “Run to completion” feature work for you in the attached example or in any other case of a flowgraph with message passing? ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [March 25, 2015, 4:50pm UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/5 "2015-03-25T16:50:38Z")
On Wed, Mar 25, 2015 at 3:11 AM, Piotr K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > ``` > > > > > processing of > > > > > I'm working on a simple gsm network monitor application based on > > I've attached vary simple flowgraph that demonstrates the problem. > > > > ``` > > the attached example or in any other case of a flowgraph with message > passing? > > – > Piotr Ah, well there’s the problem. In GRC open up “Help”-\>“Types”. The blocks you are using are the old Message Queue based blocks, not the new asynchronous message passing interface. The commit that I was talking about was specific to the async message passing, so yeah, it’d have no bearing on this. This is definitely confusing since they are both “message” based even though it’s a completely different system. The old style used here will likely be removed at some point, though it’s use persists in a few places. For your stuff, I’d avoid using this (anything with that dark grey port) and use the new async messages (the light grey ports). Tom ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [February 14, 2015, 9:35pm UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/6 "2015-02-14T21:35:52Z")
W dniu 29.04.2014 o 16:20, Tom R. pisze: > ``` > I want to use message passing in my programs (mainly in > > ``` > > Tom Hi Tom, In GNU Radio 3.7.6 this is still an issue. It’s quite serious because whole class of applications that would use message passing and rely on the processing in the flowgraph to end after processing of chunk of the signal (i.e. to change the flowgraph in known conditions) is not possible. I’m working on a simple gsm network monitor application based on gr-gsm ([GitHub - ptrkrysik/gr-gsm: Gnuradio blocks and tools for receiving GSM transmissions · GitHub](https://github.com/ptrkrysik/gr-gsm)) and have quite hard time because of this issue. Is this some general problem where the source of it is that GNU Radio was meant primarily to process stream of samples? Or is it some simpler matter? I’ve attached vary simple flowgraph that demonstrates the problem. Best Regards, Piotr K. ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [March 26, 2015, 8:41am UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/7 "2015-03-26T08:41:13Z")
W dniu 25.03.2015 o 16:48, Tom R. pisze: > ``` > > > > > > exit on last processed sample. Is this a bug? > > > > > the processing in the flowgraph to end after processing of chunk > > Is this some general problem where the source of it is that > > > > Tom > passing? > > ``` > > This is definitely confusing since they are both “message” based even > though it’s a completely different system. The old style used here > will likely be removed at some point, though it’s use persists in a > few places. For your stuff, I’d avoid using this (anything with that > dark grey port) and use the new async messages (the light grey ports). > > Tom Tom, The attached flowgraph was an example. I wanted to prepare something small that uses only GNU Radio’s message blocks, to avoid situation where I messed something in C++. The blocks that I selected were not appropriate for the situation. However in [https://github.com/ptrkrysik/gr-gsm/blob/master/apps/airprobe\_file.grc](https://github.com/ptrkrysik/gr-gsm/blob/master/apps/airprobe_file.grc) I’m using only message passing interface, but can’t get “Run to completion” to work as it should. Can you show an example of GRC flowgraph that uses message passing and exit when the input signal is over? I would greatly appreciate that as I’m a little bit stuck on this problem. – Piotr ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [April 1, 2015, 12:12pm UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/8 "2015-04-01T12:12:13Z")
Hi Piotr, nice to hear you got a step ahead! so, > * * * I’d have a blind guess: Thread 16 might be the “surviving” part of a python-spawned Timer() thread, which caused a message \_post at another thread, which might be something that hangs if that block’s thread no longer exists. Can you switch to that thread: thread 16 and then try to get a python backtrace [1] py-bt and maybe a simple C-style backtrace bt that might give you some information what is actually waiting on a condition (which is what I guess from “pthread\_cond\_wait”). Greetings, Marcus [1] for this to work, you might need to follow these instructions from [http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsGDB:](http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsGDB:) … make sure that the python development package is installed (|python-devel| on Redhatoids, |python2.7-dev| on Debianoids); for some systems, you should append the content of |/usr/share/doc/{python-devel,python2.7-dev}/gdbinit[.gz]| to your |~/.gdbinit|, and re-start |gdb|. ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [April 1, 2015, 8:35am UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/9 "2015-04-01T08:35:36Z")
W dniu 26.03.2015 o 08:39, Piotr K. pisze: > > ``` > > > > > > program doesn't > > > > > > and rely on > > > > > > Piotr K. > > > > > the attached example or in any other case of a flowgraph with message > > > > ``` > > > > have no bearing on this. > > Can you show an example of GRC flowgraph that uses message passing and Hi, Yesterday funkylab adviced me to debug the issue using GDB. The description of the method in his own words: 1. rerun cmake with -DCMAKE\_BUILD\_TYPE=RelWithDebInfo 2. rebuild and install gr-gsm 3. load the right stuff into gdb: gdb --args python apps/airprobe\_rtlsdr.py gdb will load up type run the flow graph will start to execute now, we expect it to shut down instead, parts of it continue to run, but we don’t know which, right? so at some point you just hit ctrl+z in gdb now you’re at the gdb prompt again info threads will show you the threads that are still active. If you built GNU Radio with debug info too (see the cmake thing above), you will have threads with names that look like blocks ## I did that and what I obtained was: 16 Thread 0x7fffbdffb700 (LWP 13462) “python” pthread\_cond\_wait@@GLIBC\_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86\_64/pthread\_cond\_wait.S:185 3 Thread 0x7fffe9720700 (LWP 13449) “gsm\_clock\_offs1” pthread\_cond\_timedwait@@GLIBC\_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86\_64/pthread\_cond\_timedwait.S:238 - 1 Thread 0x7ffff7fc7740 (LWP 13444) “python” 0x00007ffff78e8da3 in select () at ../sysdeps/unix/syscall-template.S:81 * * * One of the threads indicates that clock\_offset\_control block didn’t end as it should. So I disabled it for a moment and “Run to completion” started to work as it should. ## I thought that the block’s thread doesn’t end because I’ve used timer inside of it. I’ve removed almost everything from this python message only block almost everything and what was left was only this: ## class clock\_offset\_control(gr.basic\_block): def **init** (self, fc): gr.basic\_block. **init** (self, name=“gsm\_clock\_offset\_control”, in\_sig=, out\_sig=) self.message\_port\_register\_in(pmt.intern(“measurements”)) … but still - if any message enters the “measurements” input, the block’s thread doesn’t end. Conclusions: thanks to you guys (Tom R. and funkylab) I’ve finally found the source of the problem in my flowgraph. I still don’t know why is it that my python message only block doesn’t end as it should. Even if I won’t find the answer for that, I can work around the problem by implementing the block in C++ (I have many C++ message only blocks that don’t cause problems with “Run to completion”). Best Regards, Piotr K. ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [April 4, 2015, 12:32pm UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/10 "2015-04-04T12:32:25Z")
W dniu 03.04.2015 o 13:25, Piotr K. pisze: > > > > ../nptl/sysdeps/unix/sysv/linux/x86\_64/pthread\_cond\_wait.S:185 > > > > > > Greetings, > > Best Regards, > Piotr K. Hi all, Reimplementing the block that uses message passing from Python to C++ did help. The question remains - in more precisely formulated form: * * * _Why “Run to completion” doesn’t work with Python blocks that use message passing?_ * * * For anyone who wants to debug this - I’ve attached Python code demonstrating the problem to my previous message. Best Regards, Piotr K. ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [April 3, 2015, 1:27pm UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/11 "2015-04-03T13:27:28Z")
W dniu 02.04.2015 o 15:30, Piotr K. pisze: > > > 3 Thread 0x7fffe9720700 (LWP 13449) “gsm\_clock\_offs1” > > > Can you switch to that thread: > > > Marcus > > > Marcus, > > * * * > > Discuss-gnuradio mailing list > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) Marcus, I did what you recommended but my knowledge of GDB doesn’t let me interpret what I get to find the probably cause of the problem. Instead of sending output of GDB I’m sending simple python script so every interested person can see what doesn’t work. Inside the script there is one message source and one message sink. The source sends one message to the sink. At the end the program should exit but it doesn’t. Best Regards, Piotr K. ---
**Author:** ![Perper](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Perper](https://www.ruby-forum.com/u/Perper)\ **Post date:** [April 2, 2015, 3:32pm UTC](https://www.ruby-forum.com/t/run-to-completion-not-working-with-message-passing-blocks/240759/12 "2015-04-02T15:32:44Z")
W dniu 01.04.2015 o 12:10, Marcus M. pisze: > > pthread\_cond\_timedwait@@GLIBC\_2.3.2 () at > > Can you switch to that thread: > > Marcus > > [1] for this to work, you might need to follow these instructions from > [http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsGDB:](http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsGDB:) > > … make sure that the python development package is installed > (|python-devel| on Redhatoids, |python2.7-dev| on Debianoids); for > some systems, you should append the content of > |/usr/share/doc/{python-devel,python2.7-dev}/gdbinit[.gz]| to your > |~/.gdbinit|, and re-start |gdb|. Marcus, Regarding the timer - this is what I thought at first, so I removed it from the block. It didn’t help, so I removed almost everything leaving only message input of the block. But the problem persisted. I will try you advice with GDB and let everybody know of the result. Best Regards, Piotr