dorsal/arxiv
View SchemaThe CMS Event Builder
| Authors | V. Brigljevic, G. Bruno, E. Cano, S. Cittolin, A. Csilling, D. Gigi, F. Glege, R. Gomez-Reino, M. Gulmini, J. Gutleber, C. Jacobs, M. Kozlovszky, H. Larsen, I. Magrans de Abril, F. Meijers, E. Meschi, S. Murray, A. Oh, L. Orsini, L. Pollet, A. Racz, D. Samyn, P. Scharff-Hansen, C. Schwick, P. Sphicas, V. ODell, I. Suzuki, L. Berti, G. Maron, N. Toniolo, L. Zangrando, A. Ninane, S. Erhan, S. Bhattacharya, J. Branson |
|---|---|
| Categories | |
| ArXiv ID | physics/0306150 |
| URL | https://arxiv.org/abs/physics/0306150 |
Abstract
The data acquisition system of the CMS experiment at the Large Hadron Collider will employ an event builder which will combine data from about 500 data sources into full events at an aggregate throughput of 100 GByte/s. Several architectures and switch technologies have been evaluated for the DAQ Technical Design Report by measurements with test benches and by simulation. This paper describes studies of an EVB test-bench based on 64 PCs acting as data sources and data consumers and employing both Gigabit Ethernet and Myrinet technologies as the interconnect. In the case of Ethernet, protocols based on Layer-2 frames and on TCP/IP are evaluated. Results from ongoing studies, including measurements on throughput and scaling are presented. The architecture of the baseline CMS event builder will be outlined. The event builder is organised into two stages with intelligent buffers in between. The first stage contains 64 switches performing a first level of data concentration by building super-fragments from fragments of 8 data sources. The second stage combines the 64 super-fragments into full events. This architecture allows installation of the second stage of the event builder in steps, with the overall throughput scaling linearly with the number of switches in the second stage. Possible implementations of the components of the event builder are discussed and the expected performance of the full event builder is outlined.
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"abstract": "The data acquisition system of the CMS experiment at the Large Hadron\nCollider will employ an event builder which will combine data from about 500\ndata sources into full events at an aggregate throughput of 100 GByte/s.\nSeveral architectures and switch technologies have been evaluated for the DAQ\nTechnical Design Report by measurements with test benches and by simulation.\n This paper describes studies of an EVB test-bench based on 64 PCs acting as\ndata sources and data consumers and employing both Gigabit Ethernet and Myrinet\ntechnologies as the interconnect. In the case of Ethernet, protocols based on\nLayer-2 frames and on TCP/IP are evaluated. Results from ongoing studies,\nincluding measurements on throughput and scaling are presented.\n The architecture of the baseline CMS event builder will be outlined. The\nevent builder is organised into two stages with intelligent buffers in between.\nThe first stage contains 64 switches performing a first level of data\nconcentration by building super-fragments from fragments of 8 data sources. The\nsecond stage combines the 64 super-fragments into full events. This\narchitecture allows installation of the second stage of the event builder in\nsteps, with the overall throughput scaling linearly with the number of switches\nin the second stage. Possible implementations of the components of the event\nbuilder are discussed and the expected performance of the full event builder is\noutlined.",
"arxiv_id": "physics/0306150",
"authors": [
"V. Brigljevic",
"G. Bruno",
"E. Cano",
"S. Cittolin",
"A. Csilling",
"D. Gigi",
"F. Glege",
"R. Gomez-Reino",
"M. Gulmini",
"J. Gutleber",
"C. Jacobs",
"M. Kozlovszky",
"H. Larsen",
"I. Magrans de Abril",
"F. Meijers",
"E. Meschi",
"S. Murray",
"A. Oh",
"L. Orsini",
"L. Pollet",
"A. Racz",
"D. Samyn",
"P. Scharff-Hansen",
"C. Schwick",
"P. Sphicas",
"V. ODell",
"I. Suzuki",
"L. Berti",
"G. Maron",
"N. Toniolo",
"L. Zangrando",
"A. Ninane",
"S. Erhan",
"S. Bhattacharya",
"J. Branson"
],
"categories": [
"physics.ins-det"
],
"title": "The CMS Event Builder",
"url": "https://arxiv.org/abs/physics/0306150"
},
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