Speaker
Dr
Eric van Herwijnen
(CERN)
Description
LHCb has an integrated Experiment Control System (ECS), based on the commercial
SCADA system PVSS. The novelty of this control system is that, in addition to the
usual control and monitoring of all experimental equipment, it also provides control
and monitoring for software processes, namely the on-line trigger algorithms.
The trigger decisions are computed by algorithms on an event filter farm of around
2000 PCs. They are prepared using Gaudi, the LHCb software framework. Gaucho, the
GAUdi Component Helping Online, was developed to allow the control and monitoring of
Gaudi algorithms. Using Gaucho, algorithms can be monitored from the run control
system provided by the ECS. To achieve this, Gaucho implements a hierarchical control
system using Finite State Machines.
Gaucho consists of three parts: a C++ package integrated with Gaudi, the
communications package DIM, and a PVSS backend providing the user interface.
Using the PVSS user interface (the run control), algorithms can be stopped/started
and counters and histograms can be followed in real-time. The results are combined
at the level of nodes, subfarms and the full farm, so that it is easy to verify the
correct functioning of the trigger.
In this article we describe the Gaucho architecture, the experience of monitoring a
large number of software processes and some requirements for future extensions.
Primary authors
Dr
Artur Barczyk
(CERN)
Mr
Badri Damodaran
(CERN)
Dr
Beat Jost
(CERN)
Dr
Benjamin Gaidioz
(CERN)
Dr
Clara Gaspar
(CERN)
Dr
Eric van Herwijnen
(CERN)
Ms
Lana Abadie
(CERN)
Dr
Niko Neufeld
(CERN)
Dr
Richard Jacobson
(CERN)
