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May 8 – 12, 2023
Norfolk Waterside Marriott
US/Eastern timezone

GPU-based algorithms for primary vertex reconstruction at CMS

May 8, 2023, 11:45 AM
Hampton Roads Ballroom VI (Norfolk Waterside Marriott)

Hampton Roads Ballroom VI

Norfolk Waterside Marriott

235 East Main Street Norfolk, VA 23510
Oral Track 3 - Offline Computing Track 3 - Offline Computing


Erice Cid, Carlos Francisco (Boston University (US))


The high luminosity expected from the LHC during the Run 3 and, especially, the HL-LHC of data taking introduces significant challenges in the CMS event reconstruction chain. The additional computational resources needed to treat this increased quantity of data surpass the expected increase in processing power for the next years. In order to fit the projected resource envelope, CMS is re-inventing its online and offline reconstruction algorithms, with their execution on CPU+GPU platforms in mind. Track clustering and primary vertex reconstruction accounts today about 10% of the reconstruction chain at 200 pileup and involves similar computations over hundreds to thousands of reconstructed tracks. This makes it a natural candidate for the development of a GPU-based algorithm that parallelizes it dividing the work in blocks. In this contribution we discuss the physics performance as well as the runtime performance of a new vertex clustering algorithm CMS developed for heterogeneous plarforms. We'll show that the physics results achieved are better than the current CMS vertexing algorithm in production, that the algorithm is up to 8 times faster on CPU and runs as well on GPUs. We will also discuss the plans for using this algorithm in production in Run 3 and for extending it to make use of timing information provided by the CMS Phase-2 MIP Timing Detector (MTD).

Consider for long presentation No

Primary author

Erice Cid, Carlos Francisco (Boston University (US))

Presentation materials