학술논문

Effects of Adaptive Wormhole Routing in Event Builder Networks
Document Type
Conference
Source
2007 15th IEEE-NPSS Real-Time Conference Real-Time Conference, 2007 15th IEEE-NPSS. :1-7 Apr, 2007
Subject
Computing and Processing
Routing
Throughput
Collision mitigation
Data acquisition
Large Hadron Collider
Aggregates
Computer architecture
Ethernet networks
Telecommunication traffic
Network interfaces
Language
Abstract
The data acquisition system of the CMS experiment at the Large Hadron Collider features a two-stage event builder, which combines data from about 500 sources into full events at an aggregate throughput of 100 GByte/s. To meet the requirements, several architectures and interconnect technologies have been quantitatively evaluated. Both Gigabit Ethernet and Myrinet networks will be employed during the first run. Nearly full bi-section throughput can be obtained using a custom software driver for Myrinet based on barrel shifter traffic shaping. This paper discusses the use of Myrinet dual-port network interface cards supporting channel bonding to achieve virtual 5GBit/s links with adaptive routing to alleviate the throughput limitations associated with wormhole routing. Adaptive routing is not expected to be suitable for high-throughput event builder applications in high-energy physics. To corroborate this claim, results from the CMS event builder preseries installation at CERN are presented and the problems of wormhole routing networks are discussed.