As from the run 3 of CERN LHC scheduled in 2022, the upgraded ALICE experiment will use a Common Readout Unit (CRU) at the heart of the data acquisition system. The CRU, based on the PCIe40 hardware designed for LHCb, is a common interface between 3 main sub-systems: the front-end, the computing system, and the trigger and timing system. The 475 CRUs will interface 10 different sub-detectors and reduce the total data throughput from 3.5 TB/s to 635 GB/s. The ALICE common firmware framework supports data taking in continuous and triggered mode and forwards clock, trigger and slow control to the front-end electronics. In this paper, the architecture and the data-flow performance are presented.

从计划于 2022 年进行的 CERN LHC 第 3 次运行开始，升级后的 ALICE 实验将在数据采集系统的核心使用通用读出单元 (CRU)。CRU 基于为 LHCb 设计的 PCIe40 硬件，是 3 个主要子系统之间的通用接口：前端、计算系统、触发和计时系统。475 个 CRU 将连接 10 个不同的子探测器，并将总数据吞吐量从 3.5 TB/s 降低到 635 GB/s。ALICE 通用固件框架支持以连续和触发模式获取数据，并将时钟、触发和慢速控制转发到前端电子设备。在本文中，介绍了体系结构和数据流性能。