Using for Grid Jobs

Explanation courtesy of Dom Brailsford. Firstly to use the grid use

A useful explanation of can be found in the LAr Batch Tools Redmine site. This gives more detail on the specific elements.

Before Starting Grid Life

Here is a useful process to follow when you submit jobs to the gird.

  1. Copy a file locally to do some initial testing. These might be files you have made or production files. To access production files have a look at How to create and use a SAM definition. Make sure your larsoft command runs on the GPVM first.
  2. Write script
  3. Run a test sample: rather than running over all events reduce your event number and job number to 1-10\% of the sample. In can request specific memory, lifetimes and space needed. To be a good citizen you should change these e.g. in the stage you need:

    for 20GB of space required on the node, 1.5 GB of memory and expecting the job to finish within 3 hours. If you go above these then you job will be held. Roughly calculate what you need from output of the larsoft command and the size of the files. For the test job relax the parameters so they will all pass. You you are unsure what these should be set to ask.
  4. Once you test job has come back successful then you alter your requirements so that you set appropriate constraints on your requirements. Don't be too harsh otherwise your jobs will be held.
  5. If your test job fails. You can look to see why either by graphana/kibana: Checking your Grid Status, looking at the log files in the output directory/work directory or by getting the log file jobsub_fetchlog --jobid=myid. If you are not used to jobs have a read here.

How the write a XML file handles job submissions to the grid so that you don't have to worry about managing all the jobs you send to the grid yourself. runs from an XML file which defines some parameters i.e. how many jobs you want to run. So lets look at an example XML file which generates particles.

So firstly is the header section.

  • The first line is the version of XML you wish to use.
  • The lines 5-10 are for book keeping. Changing these might change your output folder structure.

Next is the project element.

  • Line 13 declares the name of the project.
  • Line 16 is the total number of events you want to produce in the sample and NOT the number of events per job.
  • Line 19 defines the operating system that you'd like the grid worker node to have.
  • Line 22 defines how the jobs are queued.

The Larsoft sub element:

  • Lines 26-28 defines the LArsoft version you would like to run. If you want to run your own version you need to make your own tar file (create a tar file using local.tar .) and place in line 28. If you want to run the UPS product then you can omit line 28. Make sure the tar file is in dCache.

Next are the stage sub-elements. This defines the generator-level job that you want to run.

  • Line 34 is where the fcl file is defined. You need to specify the full path to it.
  • Line 35 defines where the output file should go. Make sure it's a SBND dCache storage (pnfs) location.
  • Line 36 defines the work directory where initial some initial processing occurs. Make sure its a dCache area.
  • Line 37 defines how many jobs you wish to split the stage into.
  • Line 38 and 39 are definitions you need when you declare your output to SAM.

End with:

Job Submission.

Once you have written your XML script it you just need to pass a few command line arguments which define the XML and the stage name you want to use.

If you want to submit the gen-level jobs then you would, for example, do the following command: --xml prodsingle_mu_100-1257MeV_fixposcontained_fixangle.xml --stage gen --submit

It's useful to check (use checkana for anatree files) the output once a stage is finished. Do this by: --xml prodsingle_mu_100-1257MeV_fixposcontained_fixangle.xml --stage gen --check

This tell you what jobs have failed and succeeded.

For jobs which only produce an analysis file (from art::analyser) the check command is: --xml prodsingle_mu_100-1257MeV_fixposcontained_fixangle.xml --stage gen --checkana

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