학술논문

The CMS High Level Trigger System
Document Type
Conference
Source
2007 15th IEEE-NPSS Real-Time Conference Real-Time Conference, 2007 15th IEEE-NPSS. :1-4 Apr, 2007
Subject
Computing and Processing
Collision mitigation
Data acquisition
Filtering
Assembly systems
Event detection
Detectors
Software systems
Hardware
Computer architecture
Monitoring
Language
Abstract
The CMS Data Acquisition (DAQ) System relies on a purely software driven High Level Trigger (HLT) to reduce the full Level-1 accept rate of 100kHz to approximately 100Hz for archiving and later offline analysis. The HLT operates on the full information of events assembled by an event builder collecting detector data from the CMS front-end systems. The HLT software consists of a sequence of reconstruction and filtering modules executed on a farm of O(1000) CPUs built from commodity hardware. This paper presents the architecture of the CMS HLT, which integrates the CMS reconstruction framework in the online environment. The mechanisms to configure, control, and monitor the Filter Farm and the procedures to validate the filtering code within the DAQ environment are described.