Running DAQ Interface » History » Version 41

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John Freeman, 11/12/2014 02:27 PM

Running DAQInterface

DAQInterface is designed to be run, along with rest of the run control code, on, using the lbnedaq account, or on using one's personal account. For use on lbnedaqtest01, please contact John Freeman at ; these instructions will focus the use of DAQInterface on the gateway node. The code is located at /data/lbnedaq/scratch/DAQInterface/lbnerc. To get started, first setup the environment:

cd /data/lbnedaq/scratch/DAQInterface
source fireup

This will take you into the /data/lbnedaq/scratch/DAQInterface/lbnerc directory. It's a good idea to check whether lbnecontrol (the run control application) and/or DAQInterface (the component which intermediates between run control and artdaq processes) are already running; if they are, the instructions below won't work. To check this, you can try:

ps aux | grep -v grep | grep lbnecontrol
ps aux | grep -v grep | grep daqinterface

If these processes are running, it either means that someone else is using DAQInterface, or that someone else who's done with DAQInterface forgot to clean up. As the 9th and 10th fields of the row of variables "ps aux" returns concern how long the program has been running, you can use these values as well as your best judgement, then, before deciding these processes are not in active use and killing them.

Assuming the processes aren't running, before getting started, take a look at the configuration file, found in docs/config.txt (relative to /data/lbnedaq/scratch/DAQInterface/lbnerc). It should look something like the following:

lbne-artdaq: /data/lbnedaq/rce/build_lbne-artdaq

PMT host: lbnedaq3

log directory:   /data/lbnedaq/daqlogs

pause before initialization: 0

debug level: 1

BoardReader host: lbnedaq2
BoardReader port: 5205
BoardReader fhicl: /data/lbnedaq/fcl/BoardReader_TPC_lbnedaq2_1.fcl

BoardReader host: lbnedaq2
BoardReader port: 5206
BoardReader fhicl: /data/lbnedaq/fcl/BoardReader_TPC_lbnedaq2_2.fcl

EventBuilder host: lbnedaq3
EventBuilder port: 5235
EventBuilder fhicl: /data/lbnedaq/fcl/EventBuilder_lbnedaq2_1.fcl

EventBuilder host: lbnedaq3
EventBuilder port: 5236
EventBuilder fhicl: /data/lbnedaq/fcl/EventBuilder_lbnedaq2_2.fcl

Aggregator host: lbnedaq2
Aggregator port: 5265
Aggregator fhicl: /data/lbnedaq/fcl/Aggregator_lbnedaq2_1.fcl

Aggregator host: lbnedaq2
Aggregator port: 5266
Aggregator fhicl: /data/lbnedaq/fcl/Aggregator_lbnedaq2_2.fcl

The "lbne-artdaq" parameter allows the user to set the directory in which the desired build of lbne-artdaq to use is located, the "PMT host" parameter is the host on which artdaq's process management tool script (pmt.rb, used by DAQInterface to launch and kill the artdaq processes) will run, and "log directory" is the directory to which lbne-artdaq's output will be sent. The "debug level" parameter allows the user to set the verbosity level of the output to the screen; setting it to higher values creates greater verbosity, and as a practical matter, the range of settings is currently 0-3. Loosely speaking, "0" means minimal output (not much beyond simply announcing a transition is complete), "1" includes announcements of progress during transitions, "2" includes these announcements plus the values of certain variables as well as lbne-artdaq output, and "3" is primarily of developer interest. The "pause before initialization" parameter allows the user to set a pause, in seconds, between when the artdaq processes start and when they're initialized; it has been observed that a latency of a few seconds is needed for initialization to proceed correctly (though this is not always the case -- on lbne35t-gateway01, with a high setting for "debug level", a pause is not needed; the reason why "debug level" matters in this context is not yet understood).

After these individual parameters, every cluster of three lines allows one to define an artdaq process; each line should either contain "BoardReader", "EventBuilder" or "Aggregator", defining the process type, and every cluster of three lines should have the same process type. The three lines let one define the host and port of the artdaq process (to run an artdaq process on the same host as you're on, use "localhost"), as well as the FHiCL document which will be used to initialize it. Best practice is to place those FHiCL documents in the /data/lbnedaq/fcl directory. Please note that the order of processes matters, and that they should be listed front-end to back-end, i.e., BoardReader definitions should appear before EventBuilders should appear before Aggregators.

As of this writing (10/1/14) in the repo there currently exist versions of the config.txt file designed to run under different configurations; docs/config_lbnedaqtest01.txt runs simulated data on lbnedaqtest01, docs/config_lbne35t-gateway01.txt runs simulated data on lbne35t-gateway01, and docs/config_lbne35t-gateway01_RCE.txt runs RCEs on lbne35t-gateway01. If you wish to use a particular configuration, copy it into config.txt and then make any appropriate tweaks.

Once you have the configuration file written to your specifications, you can then start run control and DAQInterface:

lbnecontrol &
daqinterface -n daqint -r 5570 -c localhost -H localhost &

Here, the "daqint" argument is arbitrary, and is the name you'll give the DAQInterface process; the "5570" argument is the port off of which DAQInterface will run.

Now, you can take DAQ Interface through the standard transitions. At all stages, you can use the "lbnecmd check" command to see what state DAQInterface is in; note that you'll want to wait for a transition to complete before issuing another one, otherwise you'll receive a warning and the transition request will be ignored. Without using "lbnecmd check" you can also just look for a message like the following to know that a given transition has completed:

Initialize transition complete; if running DAQInterface in the background, can press <enter> to return to shell prompt

Note that if a high "debug level" has been set, this message can get buried in a set of output messages; in this case "lbnecmd check" may be the easiest way to determine what state the system is in.

First, take DAQInterface from the "stopped" to the "ready" state; this will create the artdaq processes on the hosts you specified, and initialize them with the FHiCL documents you specified:

lbnecmd init daq

Take DAQInterface from the "ready" to the "running" state, in order to begin datataking:

lbnecmd start daq

Pause the running of the DAQ, putting DAQInterface into the "paused" state:

lbnecmd pause daq

Resume the running of the DAQ, putting returning to the "running" state:

lbnecmd resume daq

Halt the running of the DAQ, returning DAQInterface to the "ready" state from the "running" state:

lbnecmd stop daq

Now, return to the "stopped" state, killing all the artdaq processes:

lbnecmd terminate daq

  • Running with the configuration manager set up

Note that the rules for running DAQInterface when the configuration manager is used are slightly different than above. The primary issue to keep in mind is that for a given configuration and set of chosen components, the BoardReaderMain and AggregatorMain applications (as well as their hosts and FHiCL documents) will be determined by run control and the configuration manager; thus these applications need not be listed in the docs/config.txt. Indeed, the only applications to list in docs/config.txt are the EventBuilderMain applications, as these deal with details internal to DAQInterface / artdaq (unlike BoardReaderMain, which contains experiment-defined fragment generators, and AggregatorMain, which contains experiment-defined Art modules).

  • Error handling
    As of this writing (7/14/14) there has not yet been extensive user feedback concerning DAQInterface; despite this, certain potential problems have been anticipated and are handled within DAQInterface. These problems include:
    1. An artdaq process returns an error state after a transition request, or an exception is thrown by the XML-RPC library during the request
    2. During periodic checks, one or more artdaq processes expected to exist are not found

In either case, an error is reported via 0MQ to run control, and the "Recover" transition is automatically triggered. This transition is a fairly blunt instrument: it will kill any remaining artdaq processes and return DAQInterface to its original state of "stopped" (i.e., one in which it requires the "init" transition before anything else is done).

In order to see this for yourself, you can deliberately sabotage one of the transitions. E.g., you can replace one of these filenames listed in the config.txt file with one of your own files intentionally designed to be improper FHiCL; this will then trigger a "recover" transition automatically when an "init" transition is requested. The same thing will occur if you use the name of a file which doesn't exist. After the "recover" transition, you can then use the "lbnecmd check" command to see for yourself that DAQ Interface has returned to its original state. Note that currently, if recover sees that the artdaq processes don't exist, it will raise an exception, which will in turn trigger DAQInterface to end itself. In general, setting "debug level" to a high value is a good idea for troubleshooting if something goes wrong (although a sufficiently high value may simply obscure things for the end user).

Please note that if you issue an "init" transition and then follow it with a "terminate" transition, you'll see an exception in the artdaq terminal window which looks like the snippet below; this is because statistics collection which occurs during termination will fail if no data's been collected, which is expected:

Tue Jul 08 14:16:33 -0500 2014:  Time Summary: 
Tue Jul 08 14:16:33 -0500 2014:  Min: 0
Tue Jul 08 14:16:33 -0500 2014:  Max: 0
Tue Jul 08 14:16:33 -0500 2014:  Avg: inf
Tue Jul 08 14:16:33 -0500 2014: %MSG-s ArtException:  Aggregator-lbnedaqtest01-5265 JobSetup
Tue Jul 08 14:16:33 -0500 2014: cet::exception caught in art
Tue Jul 08 14:16:33 -0500 2014: ---- DataCorruption BEGIN
Tue Jul 08 14:16:33 -0500 2014:   NetMonInputDetail: Could not receive message!
Tue Jul 08 14:16:33 -0500 2014: ---- DataCorruption END
Tue Jul 08 14:16:33 -0500 2014: %MSG
Tue Jul 08 14:16:33 -0500 2014: %MSG-s ArtException:  Aggregator-lbnedaqtest01-5266 JobSetup
Tue Jul 08 14:16:33 -0500 2014: cet::exception caught in art
Tue Jul 08 14:16:33 -0500 2014: ---- DataCorruption BEGIN
Tue Jul 08 14:16:33 -0500 2014:   NetMonInputDetail: Could not receive message!
Tue Jul 08 14:16:33 -0500 2014: ---- DataCorruption END
  • Troubleshooting
    • Your change to doesn't seem to do anything
      Make sure you kill the existing daqinterface process and restart it
    • On the initial transition ("lbnecmd init daq"), you see "error: [Errno 111] Connection refused"
      If a "Recover" is triggered and you can see via "lbnecmd check" that DAQInterface is in the "stopped" state, try initializing again. If that doesn't work, you can try increasing the value of the "pause before initialization" variable in the docs/config.txt file. Empirically, it appears there needs to be a pause of at least 4 seconds on before the FHiCL documents can be successfully sent via XML-RPC to the processes; increasing this value may make it less likely that the "Connection refused" error occurs.