CMS High Level Trigger Configuration Management

1. CMS High Level Trigger Configuration Management Computing in High Energy Physics, Victoria BC September 3, 2007 Emilio Meschi – CERN PH/CMD

2. ~108 electronics channels, 40 MHz crossing rate Two trigger levels: L1 (hardware)  100 kHz max accept rate Event building at full L1 rate High Level Trigger (software)  200 Hz Event Filter Filter Farm O(1000) systems execute HLT algos Data logging system 1GB/s, 250TB capacity CMS Data Acquisition System HLT decision ~40 ms/event • Events fully built in • worker node memory EM - CMS HLT Configuration Management - CHEP07

3. HLT: Design Considerations • Online and Offline reconstruction/selection: one reconstruction framework • Maximum flexibility • Wider community of developers • Faster migration of algorithms developed offline • HLT steering • Instances of algorithms and filters provide selection of particular category of events • arranged and executed in strict sequence (trigger path) • Each path executed up to first negative filter decision or to the end • Every path executed for every event (guarantees traceability) EM - CMS HLT Configuration Management - CHEP07

4. HLT and Offline • CMS reconstruction framework • Modular architecture, enforcing component interfaces • Input, reconstruction, filtering, access to calibrations etc. • Modules loaded and configured at initialization using plug-in system • Object representation of configuration completely defines instances of algorithms, their parameters and the sequence of execution • Different grammars map object model to provide flexible file-based configuration of offline jobs • Offline HLT development and benchmarking • Algorithm development and MC physics benchmarking • Integration of trigger paths • Integration of initial table • CPU performance and first optimization • See talk by L.Apanasevich, this session EM - CMS HLT Configuration Management - CHEP07

5. Offline ‘HLT’ Plugin declaration Configuration subdocument Module parametrization Offline job Trigger Table Output EM - CMS HLT Configuration Management - CHEP07

6. HLT and Online Systems • Online framework (XDAQ) • Provides plug-in mechanism: ‘executive’ program loads online components • Dispatches control message • Provides data transport in a distributed environment • Integration: enable DAQ process to load offline modules and define special interfaces for input/output, control, and monitoring • Run Control • Deploys online applications in XDAQ distributed environment • Configures and controls distributed system using tree of state machines (Function Managers) • presentation by A. Oh in this track (Thursday) • HLT Configuration and control: HLT Function Manager (HLTS) • At configuration, loads trigger table upon instruction of Run Control • Retrieves actual configuration ‘document’ and distributes to Filter Farm processes EM - CMS HLT Configuration Management - CHEP07

7. HLT Configuration Management • File based system issues • Concurrent versioning of multiple tables technically difficult • Hard to maintain in the long term: • evolution of the grammar and algorithms • Potential consistency problems in distributed environment • CLOBs only partially address 1 And 2 • Configuration Management: requirements • Abstract DB model of framework components and of trigger table • Little or no dependence of configuration grammar • Populate table in DB based on specific software version • automatic migration to different version • Unique table identification in the system for online use • Automatic conversion to specific grammar • Graphical user interface • Additionally • Support offline development/validation workflow of HLT algorithms EM - CMS HLT Configuration Management - CHEP07

8. FILTER FARM Configuration Management System DATABASE Describe relation between services, paths, modules and parameter Enable creation of table based on templates in the db. Enforce basic rules Provide table traversal TEMPLATES HLT CONFIGURATIONS Discover all relevant sw components and store templates in db for given sw release GUI DB INTERFACE CONVERTER PARSER Provide retrieval and conversion of table to different formats RUN CONTROL CONVERTER SOURCE CODE EM - CMS HLT Configuration Management - CHEP07

9. Components I • Database: relational schema • Store algorithms and parameter defaults in templates from parsing of sw release • Store configuration as references to paths, paths as sequences of module instances • Module instances as references to respective template plus set of non-default parameters • Oracle and MySQL compatible • Parser: python scripts • Traverse source tree of reconstruction software release • Discover all components and their parameters, plus default values • Traverses 1.5 MSLOC (CMS reconstruction) in ~1 min EM - CMS HLT Configuration Management - CHEP07

10. Components II • Graphical User Interface: java application • Load template definitions from DB • Configuration displayed as tree • Context menus filled from template info to populate configuration • Enforces basic configuration rules and consistency • Converter: java API • Accesses database to retrieve configuration and translate into valid grammar or other representation • E.g. html for easy navigation of table (for physicists, or the curious) • API used by Run Control to configure filter farm • Web service for global access to HLT configurations in use EM - CMS HLT Configuration Management - CHEP07

11. GUI Screenshot Configuration properties • Drag and drop, db migration • sw version update • quick document generation Module details Configuration tree EM - CMS HLT Configuration Management - CHEP07

12. HLT Configuration Workflow EM - CMS HLT Configuration Management - CHEP07

13. Summary • HLT Configuration Management System designed to • Support online validation and operation of HLT configurations and their long term maintenance • Help offline development and validation of HLT algorithms and tables • Currently under commissioning as part of the HLT validation effort • Complex, realistic trigger table (~100 paths) • From HLT “exercise” benchmark mentioned previously • Simulated input (raw data from MC events) • Benchmark of performance and stability of algorithms • Also in use for detector commissioning • No physics selection but realistic environment • Configuration of basic reconstruction (reformatting, data consistency, local reconstruction) and monitoring • Test of online workflow, scalability EM - CMS HLT Configuration Management - CHEP07