Re: [Discuss-gnuradio] Stop GRC flow graph after defined time
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi Activecat! On 02.02.2014 03:30, Activecat wrote: Thanks. This solves the problem completely. :) Cool. In summary, to stop the flowgraph when the source is empty, we need to: 1). The source block's work() method returns WORK_DONE ( which is -1 ) 2). The sink block's work() method returns noutput_items Well, 2. is not really true. To explain the mechanism (to understand better, maybe read about sync, fixed ratio and general_work blocks in the wiki): In normal operation, when a block downstream is finished with one iteration of work, the scheduler knows how much items on its input buffer have been consumed, determining the free space for the upstream work(), since that work's output is the same as the formers input buffer, to avoid unnecessary copying. So, if an upstream block says hey, I'm done forever (WORK_DONE), then the scheduler knows that there is nothing new to do for the downstream block. It therefore continues to process the samples that are still in buffers, until there are no blocks that could produce any output since there is not enough input anymore. So, in summary: 1) yes, 2) the downstream blocks are used as long as there is still work to do. Which of course will end fastest when they consume all their input items. Additional Questions: 1). In general, shouldn't a sink block's work() method always return 0 instead of noutput_items? (Sink block doesn't produce any output, isn't the number of output produced is zero?) You should define your sink's output IO signature to have an itemsize of zero on all zero output streams. Since sinks are usually sync blocks, there are as many output as input samples; if the former are of size 0, then there are no buffers to shuffle around, though you can still tell the runtime that you produced X samples, consuming X. alternatively, return 0 and call consume_each(X) before. 2). In practical cases, under what circumstances we should let the source block's work() method return 0? Never, unless you really can't produce nothing. If your block is sync, your flowgraph will start to stall. When it returns 0, the sceduler will still continue to call the source block's work() method repeatly. That sounds only right to me if downstream blocks don't consume all available buffer at once. The flowgraph will usually stop if a block consumes 0 input items, since the runtime then assumes the block can't process anymore. 3). Under what scenario we will need to use the stop() method ? (In python script we see stop() method quit often, but it seems never needed in c++ code) Wrong perspective: In Flowgraph code you often see start() stop() since it is used to manage flowgraphs from a higher view. inside work functions, you should never call stop(). Just say you're WORK_DONE, since you can't say anything about the work in progress at the rest of the flowgraph. Let the runtime manage shutting down the FG. If your FG doesn't contain message passing blocks (not even inside hier blocks), the python main program will stop when it's done, I'm fairly certain. Can you share more about your flowgraph? Greetings Marcus -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJS7s8MAAoJEAFxB7BbsDrLDasIAKYsY5a8MWMQxFISgedcKYMw g4zmcyJM7Uo449GRCh3XZf7f7tkc8+hZldi2w24ECHmEkpnFDBZZxww1alyBzBpu t9TPjrFtNdAaWfZcA7L9C8EGX27BUYrxf62uk04r4gEfBw0x7GPg2qWjr2JqYEJP +piqpu+QFLWNi0iZH9v+OR40N1k0de4FQ9TtT2GjQnGsHCS6u0cIhv7pfZPyTDA9 jyhGTYmF9dIAq1gfo7Gl4BErtczHXPYu6JqEvg6bD+whUUWIuH+GT73ohxQVA0VF T8uSh/Awhu1W0OO52ZMrvgBnlmB3j0/Ibe3rYSRlsmra86EROKD2zL3UJY92jLA= =oZ7k -END PGP SIGNATURE- ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Stop GRC flow graph after defined time
Dear Marcus,
Thanks for thorough explanation.
Let me summarize the information, as below.
Correct me if I am wrong.
1). For sink block derived from gr::sync_block, its work() function should
return noutput_items,
even though sink block doesn't produce any output.
This is a norm.
2). We could opt to let the above work() function returns 0 instead of
noutput_items.
In this case it should call consume_each(noutput_items) before the
return.
All other remain the same, this should work.
3). Can we derive a sink block from gr::block ?
In this case we must explicitly call consume_each(noutput_items) in
its general_work() function.
Should the general_work() return 0, or return noutput_items, or
either one will do?
The forecast() is defined to include
ninput_items_required[0] = noutput_items;
Question 1:
Sink block doesn't produce any output, hence, noutput_items=0.
If this noutput_items has a non-zero value, what does this value means, how
is it calculated?
Question 2:
Referring to
http://gnuradio.org/redmine/projects/gnuradio/wiki/OutOfTreeModules#Sources-and-sinks
it says that Sources and sinks are derived from gr::sync_block.
Why should sink block be categorised as sync block?
Sync block is defined as block that has the same number of input items and
output items,
but sink block doesn't fulfill this condition (sink block has no output).
Regards,
activecat
Note:
My flow graph is very simple. It consists of only two blocks, namely a
source block and a sink block.
The source block sends out a series of integer numbers.
The sink block receives the integers, and print it out (std::cout).
Below is the code of the sink block.
Filename: gr-activecat/lib/integer_sink_impl.cc
namespace gr {
namespace activecat {
integer_sink::sptr integer_sink::make()
{ return gnuradio::get_initial_sptr (new integer_sink_impl()); }
// private constructor
integer_sink_impl::integer_sink_impl()
: gr_sync_block(integer_sink,
gr_make_io_signature( 1, 1, sizeof(int) ),
gr_make_io_signature( 0, 0, 0 ))
{ }
// virtual destructor
integer_sink_impl::~integer_sink_impl()
{ }
int
integer_sink_impl::work( int noutput_items,
gr_vector_const_void_star input_items,
gr_vector_void_star output_items)
{
const int *in = (const int *) input_items[0];
std::cout integer_sink receives: ;
for (int i=0; i noutput_items; i++)
std::cout in[i] , ;
std::cout std::endl;
return noutput_items; // Don't return 0, else the flowgraph won't
stop even after the source block's work() fucntion return -1
}
} /* namespace activecat */
} /* namespace gr */
On Mon, Feb 3, 2014 at 7:04 AM, Marcus Müller mar...@hostalia.de wrote:
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Hi Activecat!
On 02.02.2014 03:30, Activecat wrote:
Thanks. This solves the problem completely.
:) Cool.
In summary, to stop the flowgraph when the source is empty, we need
to: 1). The source block's work() method returns WORK_DONE (
which is -1 ) 2). The sink block's work() method returns
noutput_items
Well, 2. is not really true.
To explain the mechanism (to understand better, maybe read about sync,
fixed ratio and general_work blocks in the wiki):
In normal operation, when a block downstream is finished with one
iteration of work, the scheduler knows how much items on its input
buffer have been consumed, determining the free space for the upstream
work(), since that work's output is the same as the formers input
buffer, to avoid unnecessary copying.
So, if an upstream block says hey, I'm done forever (WORK_DONE),
then the scheduler knows that there is nothing new to do for the
downstream block.
It therefore continues to process the samples that are still in
buffers, until there are no blocks that could produce any output since
there is not enough input anymore.
So, in summary:
1) yes,
2) the downstream blocks are used as long as there is still work to do.
Which of course will end fastest when they consume all their input items.
Additional Questions: 1). In general, shouldn't a sink block's
work() method always return 0 instead of noutput_items? (Sink
block doesn't produce any output, isn't the number of output
produced is zero?)
You should define your sink's output IO signature to have an itemsize
of zero on all zero output streams. Since sinks are usually sync
blocks, there are as many output as input samples; if the former are
of size 0, then there are no buffers to shuffle around, though you can
still tell the runtime that you produced X samples, consuming X.
alternatively, return 0 and call consume_each(X) before.
2). In practical cases, under what circumstances we should let the
source block's work() method return 0?
Never, unless you really can't produce nothing. If your block is sync,
your
Re: [Discuss-gnuradio] Stop GRC flow graph after defined time
Dear Josh, Your method below doesn't work on GNU Radio v3.6.5.1 In this case, how to stop the flow graph in v3.6.5.1 ..? Thanks regards, activecat Subject: Re: [Discuss-gnuradio] Stop GRC flow graph after defined time Date: Wed, 29 Sep 2010 08:33:49 -0700 User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.12) Gecko/20100915 Thunderbird/3.0.8 You can use the Misc-Head block to limit the samples. Then set the flow graph options to run to completion, this option is only available in non-gui mode. See the options blocks. -Josh On 09/29/2010 04:31 AM, Thorsten Laude wrote: Hallo, I'm executing a flow graph in GRC and want to stop this flow graph after some defined time, for example 3 seconds, or after a defined amount of samples. Currently I stop the flow graph by clicking on Kill the flow graph. How can I implement, that the flow graph is stopped automatically? Thorsten ___ Discuss-gnuradio mailing list address@hidden http://lists.gnu.org/mailman/listinfo/discuss-gnuradio http://lists.gnu.org/archive/html/discuss-gnuradio/2010-09/msg00420.html ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Stop GRC flow graph after defined time
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 That run-to-completion method has never failed me; the only explanation for that kind of behavior would be if your flowgraph employed message passing. Is that the case? Anyway, to make GNU Radio stop the flowgraph when your source is empty, you shouldn't call stop(). The source's work() method returns the number of produced items. A zero there should make the flowgraph realize you're done. If you want it explicitely (and right), let the work method return WORK_DONE (==-1). Greetings, Marcus On 01.02.2014 13:57, Activecat wrote: Dear Josh, Your method below doesn't work on GNU Radio v3.6.5.1 In this case, how to stop the flow graph in v3.6.5.1 ..? Thanks regards, activecat Subject: Re: [Discuss-gnuradio] Stop GRC flow graph after defined time Date: Wed, 29 Sep 2010 08:33:49 -0700 User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.12) Gecko/20100915 Thunderbird/3.0.8 You can use the Misc-Head block to limit the samples. Then set the flow graph options to run to completion, this option is only available in non-gui mode. See the options blocks. -Josh On 09/29/2010 04:31 AM, Thorsten Laude wrote: Hallo, I'm executing a flow graph in GRC and want to stop this flow graph after some defined time, for example 3 seconds, or after a defined amount of samples. Currently I stop the flow graph by clicking on Kill the flow graph. How can I implement, that the flow graph is stopped automatically? Thorsten ___ Discuss-gnuradio mailing list address@hidden http://lists.gnu.org/mailman/listinfo/discuss-gnuradio http://lists.gnu.org/archive/html/discuss-gnuradio/2010-09/msg00420.html ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJS7TW6AAoJEAFxB7BbsDrL50kH/3hvueTfOvJP1WG+7zEd263u RTaeaSg8Y3Hh6rfsp1G2iq6EEogyR6QfToBeSJjAM8f1dA9fV1yU+iV09L3pwo87 0vWst6AP03316umqH+nj2WiKsEfcV5QaZNEkNKYZfYuFj1Xqi1c/h1M9JOfWGSII 3JgndjvPR7eALLX8NxJtXQGwnwR0lEZFPiA2eCJAZsRSRBOr8Vzd0thunZrZmcYZ QnMK+svY84XmZhYBlkyC1X7heil/zb2r/pG2C57GojTGXgS1pdPy5HqU4f4eB2iK o/4DLy8/PN+pBORDryvrTX0AU7HHfJxtkLUlct/jGnCnHGGLWR8eWcVoE10UPgc= =M1pB -END PGP SIGNATURE- ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Stop GRC flow graph after defined time
Dear Marcus, Thanks. This solves the problem completely. In summary, to stop the flowgraph when the source is empty, we need to: 1). The source block's work() method returns WORK_DONE ( which is -1 ) 2). The sink block's work() method returns noutput_items Additional Questions: 1). In general, shouldn't a sink block's work() method always return 0 instead of noutput_items? (Sink block doesn't produce any output, isn't the number of output produced is zero?) 2). In practical cases, under what circumstances we should let the source block's work() method return 0? When it returns 0, the sceduler will still continue to call the source block's work() method repeatly. 3). Under what scenario we will need to use the stop() method ? (In python script we see stop() method quit often, but it seems never needed in c++ code) Thanks. activecat Note: This flow graph doesn't involve any message passing at all. On Sun, Feb 2, 2014 at 1:58 AM, Marcus Müller mar...@hostalia.de wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 That run-to-completion method has never failed me; the only explanation for that kind of behavior would be if your flowgraph employed message passing. Is that the case? Anyway, to make GNU Radio stop the flowgraph when your source is empty, you shouldn't call stop(). The source's work() method returns the number of produced items. A zero there should make the flowgraph realize you're done. If you want it explicitely (and right), let the work method return WORK_DONE (==-1). Greetings, Marcus On 01.02.2014 13:57, Activecat wrote: Dear Josh, Your method below doesn't work on GNU Radio v3.6.5.1 In this case, how to stop the flow graph in v3.6.5.1 ..? Thanks regards, activecat Subject: Re: [Discuss-gnuradio] Stop GRC flow graph after defined time Date: Wed, 29 Sep 2010 08:33:49 -0700 User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.12) Gecko/20100915 Thunderbird/3.0.8 You can use the Misc-Head block to limit the samples. Then set the flow graph options to run to completion, this option is only available in non-gui mode. See the options blocks. -Josh On 09/29/2010 04:31 AM, Thorsten Laude wrote: Hallo, I'm executing a flow graph in GRC and want to stop this flow graph after some defined time, for example 3 seconds, or after a defined amount of samples. Currently I stop the flow graph by clicking on Kill the flow graph. How can I implement, that the flow graph is stopped automatically? Thorsten ___ Discuss-gnuradio mailing list address@hidden http://lists.gnu.org/mailman/listinfo/discuss-gnuradio http://lists.gnu.org/archive/html/discuss-gnuradio/2010-09/msg00420.html ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJS7TW6AAoJEAFxB7BbsDrL50kH/3hvueTfOvJP1WG+7zEd263u RTaeaSg8Y3Hh6rfsp1G2iq6EEogyR6QfToBeSJjAM8f1dA9fV1yU+iV09L3pwo87 0vWst6AP03316umqH+nj2WiKsEfcV5QaZNEkNKYZfYuFj1Xqi1c/h1M9JOfWGSII 3JgndjvPR7eALLX8NxJtXQGwnwR0lEZFPiA2eCJAZsRSRBOr8Vzd0thunZrZmcYZ QnMK+svY84XmZhYBlkyC1X7heil/zb2r/pG2C57GojTGXgS1pdPy5HqU4f4eB2iK o/4DLy8/PN+pBORDryvrTX0AU7HHfJxtkLUlct/jGnCnHGGLWR8eWcVoE10UPgc= =M1pB -END PGP SIGNATURE- ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Stop GRC flow graph after defined time
Hallo, I'm executing a flow graph in GRC and want to stop this flow graph after some defined time, for example 3 seconds, or after a defined amount of samples. Currently I stop the flow graph by clicking on Kill the flow graph. How can I implement, that the flow graph is stopped automatically? Thorsten ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Stop GRC flow graph after defined time
You can use the Misc-Head block to limit the samples. Then set the flow graph options to run to completion, this option is only available in non-gui mode. See the options blocks. -Josh On 09/29/2010 04:31 AM, Thorsten Laude wrote: Hallo, I'm executing a flow graph in GRC and want to stop this flow graph after some defined time, for example 3 seconds, or after a defined amount of samples. Currently I stop the flow graph by clicking on Kill the flow graph. How can I implement, that the flow graph is stopped automatically? Thorsten ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
