Trigger Validation

Last update: 18 Nov 2020 [History] [Edit]

Nightly tests

The Trigger software is regularly tested in each nightly release build with ART (ATLAS Release Tester), which executes two series of tests:

  • ART local executed on a single machine (per release) at CERN directly after the nightly release is built
  • ART grid where each test is submitted as a job to the Grid

The local tests are short (no longer than 1 hour, but typically 5-10 minutes) and run on fewer events (20-100) and the full results are available in the morning, whereas the grid tests typically run on a larger sample (500-1000 events) and some of them may take more than 10h.

Trigger ART tests are organised in four packages:

  • TriggerTest - running trigger with offline athena with various menu configurations
  • TrigAnalysisTest - jobs testing integration of the trigger with offline workflows and analysis tools, typically using Reco_tf to steer the execution
  • TrigP1Test - running trigger with athenaHLT to test all workflows relevant for P1 operation in a similar environment
  • TrigUpgradeTest - temporary package originally created for AthenaMT upgrade, now being decommissioned as AthenaMT became the standard production software

Each package contains a test directory where each ART test is defined as a separate python or shell script. All these scripts are installed in the release and can be executed directly (see the next section). The naming convention is test_PKG_NAME_TYPE where PKG is trig/trigAna/trigP1/trigUpgr corresponding to each of the four packages, NAME describes the test and typically includes a string identifying the menu (e.g. “v1PhysP1” for the PhysicsP1_pp_run3_v1 menu), and TYPE is either build (for ART local) or grid (for ART grid).

Trigger ART Monitor website

Results of all local and grid ART tests are available in the Trigger ART Monitor page:

An introduction to the page and what it offers was presented in the 28/08/2019 TGM.

Trigger counts monitoring

to be added - work in progress

Trigger EDM size monitoring

to be added - work in progress

Unit tests

Each athena package may define a set of unit tests in its CMakeLists.txt. Unit tests should be very short (order of 1 minute) jobs which test a specific functionality contained within this package and with minimal dependency on other packages. More information on how to define such a test is available in SoftwareTutorialBasicCMake#Tests. The unit tests for all packages are executed as part of the nightly release build procedures and also as part of Merge Request testing (see below)

Testing during development

When writing code

While developing trigger software, the developer would typically run a single test of their choice corresponding the most to what they are changing. For example, if you are developing muon triggers, you would most likely run a muon slice build test running on a signal (ttbar) MC sample, In order to do this, simply type in the script name and hit Enter. Tab auto-completion is available since the tests are installed in the release. For example:

asetup Athena,master,latest
source your-build-dir/architecture-tag/

Before submitting a Merge Request

1. Use
Each developer should run a wider set of tests to make sure their changes are well integrated with other parts of the software. In order to facilitate this testing, a helper script is available. It provides several modes of running (run with --help to see all), but the most common use case would be the -m option which runs a minimal set of tests giving a good coverage of most cases. Use option -jN to run the tests in N parallel jobs. Option -d allows to only print the tests which would be executed in order to learn which they are. At the time of writing, running the minimal local tests covers four ART local tests:

$ -m -j4
INFO     The following 4 tests will be executed: 
(then the results follow after tests are finished)

The full results of each test are also available in the runTrigART/results/runTrigART directory created by the script.

In case reports trigger count changes, follow the instructions in the corresponding section below.

2. Use ctest
You should also run all unit tests for the packages you modified. This can be done by running the ctest command from CMake in the build directory. Type --help for all options - the most common are -jN to run N parallel jobs, -N to list all available tests, --output-on-failure to print the output to stdout if a test fails, and --rerun-failed to run only those tests which didn’t succeed in the previous execution. Example:

ctest -j4 --output-on-failure --rerun-failed

Continuous Integration tests

Each Merge Request (MR) to the athena repository triggers a Continuous Integration (CI) pipeline running the following steps:

  1. Compile athena external dependencies
  2. Compile athena including changes submitted in the MR
  3. Run unit tests only for the packages affected by the MR
  4. Run a pre-defined fixed set of CI tests

The last step includes integration tests covering all domains of ATLAS software for a given project (Athena, AthSimulation, AthAnalysis, etc.) with configuration defined in the atlas-sit/CI repository. Currently there are three sets of tests executed for Trigger, running athena on data, athena on MC and athenaHLT on data. The Trigger CI tests are simply executing a pre-defined set of Trigger ART local (“build”) tests. The configuration is as follows:

branch, project Trigger_athena_data Trigger_athena_MC Trigger_athenaHLT
master, Athena[!][!]
21.3, Athena
21.0, Athena -

Updating reference files for MRs changing trigger counts

The tests marked in green and with [!] in the table above include a step comparing trigger counts in the log file to a reference located in the source tree of athena. Any MR changing these counts must include update of these references as part of the submitted change set. In order to do this, run the affected test in any of the above ways - either directly or with -m and follow the instructions printed by chainComp. For example, running may result in the following printout:

chainComp INFO     Test file:
chainComp INFO     Reference file: /myWorkArea/build/x86_64-centos7-gcc8-opt/data/TriggerTest/ref_data_v1Dev_build.ref
chainComp INFO     Found 1 new chain added:
chainComp INFO       HLT_j45_pf_subjesgscIS_ftf_boffperf_split_L1J20
chainComp INFO     Found 1 chain removed:
chainComp INFO       HLT_2mu5_bUpsimumu_L12MU4
chainComp INFO     Found 3 chains with count differences:
chainComp INFO       HLT_e3_etcut1step_g5_etcut_L12EM3:
chainComp INFO         eventCount: 8 -> 10
chainComp INFO         stepCounts:
chainComp INFO           1: 8 -> 10
chainComp INFO           2: 8 -> 10
chainComp INFO         stepFeatures:
chainComp INFO           1: 20 -> 23
chainComp INFO           2: 20 -> 23
chainComp INFO       HLT_e5_etcut_L1EM3:
chainComp INFO         stepFeatures:
chainComp INFO           1: 123 -> 148
chainComp INFO       HLT_g5_tight_L1EM3:
chainComp INFO         eventCount: 0 -> 1
chainComp INFO         stepCounts:
chainComp INFO           3: 0 -> 1
chainComp INFO         stepFeatures:
chainComp INFO           3: 0 -> 1
chainComp ERROR    Trigger counts differ from the reference. If the above differences are intended, update the reference
chainComp INFO     Patch file created. To apply, run in the athena source directory:
chainComp INFO     git apply /myWorkArea/build/runTrigART/results/runTrigART/test_trig_data_v1Dev_build/ref_data_v1Dev_build.patch
chainComp INFO     Then check with git diff and, if everything is correct, add and commit

In this case the following steps are required:

  1. Verify that the printed differences are all intended and expected.
  2. Go to the athena source directory.
  3. Execute the git apply command printed by chainComp.
  4. Check again with git diff if the changes are as expected.
  5. If everything looks good, stage the updated file with git add and then commit and push to your branch.

NB1: After running both tests relying on reference comparison, it is perfectly fine (even recommended) to execute the suggested git apply commands from both tests one after another and then add them to a single commit.

NB2: It is currently not possible to download the reference patch file directly from CI machines. When the reference comparison fails in CI, the patch will be printed to the log and can be copied as text from there. You can create a patch file locally by pasting the contents, and use the same git apply command with this file.

NB3: A walkthrough video is available below, presenting trigger (menu) development process from checking out the repository through testing and updating the references to pushing a new branch ready for opening a MR.

Large-stat MC and data validation

In addition to CI and nightly tests, regular large-statistics validation campaigns with MC and data are organised regularly by the Trigger Group. Specifically these are:

Sample A validation

Organised by the Trigger Release & Validation Coordinators. Running full MC production chain including trigger on 100k ttbar events and often also other samples. Histograms are produced using the PhysicsValidation transform and compared to a reference produced in the same way in a web display. Checked by Trigger Validation contacts from Signature Groups.

Sample T validation

Organised by the Trigger Release & Validation Coordinators and Trigger Menus & Performance Coordinators. Running full MC production chain including trigger on small MC samples (10k events) for a large set of physics processes. These samples provide input for trigger performance studies for physics groups. Checked by analysis groups in coordination with Trigger representatives of the corresponding physics group.

HLT data reprocessing

Organised by the Trigger Operations & Data Quality Coordinators. Rerunning HLT with an updated menu on EnhancedBias stream collision data recorded earlier, followed by full offline reconstruction and monitoring like at Tier0. The results are compared with web display to a reference produced in the same way. Checked by Trigger Signature Group On-Call Experts with support of the Trigger Validation contacts of each group.

Frequently Asked Questions

What is the athena command running in test X?
There are two ways to check this - with the ART Monitor website or by running locally. To check in the website, navigate to the result for the test of interest and check its outputs as follows:

  1. Go to the website
  2. Follow the “[Expertpage]” link next to a recent date for either build or grid results, depending on your interest.
  3. Select branch and project, e.g. master_Athena_x86_64-centos7-gcc8-opt and then package, e.g. TriggerTest
  4. Click on dir in the Links column next to the test of your interest.
  5. See the file commands.json or directly in the stdout log.

To check locally, you can execute a test in ‘dry mode’, which only configures the steps without really running them. This only works for tests run with python scripts, not for the deprecated shell script versions. To run in dry mode, set the corresponding environment variable for the test, for example:


will print all steps with the corresponding commands and also create the commands.json file.

How to run reconstruction on HLT output?
One can run HLT with many kinds of input and output formats, but not all outputs can be fully used for further processing. The table below lists all possible combinations in which HLT can be run and the level of support for reconstruction of the outputs. Names of example ART tests which validate the corresponding HLT+reco chain are also given. When chains of commands are run for HLT+reco, transform wrappers around the athena[HLT] commands are often used: Reco_tf and Trig_reco_tf. “Limited” support means that the output may be missing some information needed for full offline reconstruction (e.g. detector data), but it will still include the HLT objects.

Command Input type Input format Output format Reconstruction support Test data BS BS yes, critical test_trigP1_v1PhysP1_T0Mon[Trf]_build MC RDO RDO_TRIG yes, critical test_trigAna_RDOtoAOD_mt1_build MC RDO BS limited currently no reco test data BS BS limited test_trigAna_BStoBStoESDAOD_mt1_build data BS RDO_TRIG limited currently no reco test