论文标题
LHC运行期间爱丽丝的基于GPU的重建和数据压缩3
GPU-based reconstruction and data compression at ALICE during LHC Run 3
论文作者
论文摘要
在LHC运行3中，爱丽丝将从最小偏差PB-PB碰撞中将数据率显着提高到50 kHz的连续读取。在线脱机计算升级的重建策略可以预见到在数据采用探测器校准的数据期间的第一个同步在线重建阶段，以及后验校准的异步重建阶段。数据速率的显着提高给在线和离线重建以及数据压缩带来了挑战。与运行2相比，在线农场必须每秒处理50倍的事件并获得更高的数据压缩因子。爱丽丝将依靠GPU来实时执行时间投影室（TPC）检测器的实时处理和数据压缩，这是数据速率的最大贡献者。借助在线农场中的GPU，我们还评估了它们在硅内部跟踪系统（ITS）和过渡辐射探测器（TRD）的异步重建过程中的全面跟踪链的使用情况。该软件是以通用的方式编写的，因此它也可以在WLCG上具有相同重建输出的处理器上运行。我们概述了重建的状态和当前性能以及在GPU上的TPC和全局重建的数据压缩实现。
In LHC Run 3, ALICE will increase the data taking rate significantly to 50 kHz continuous read out of minimum bias Pb-Pb collisions. The reconstruction strategy of the online offline computing upgrade foresees a first synchronous online reconstruction stage during data taking enabling detector calibration, and a posterior calibrated asynchronous reconstruction stage. The significant increase in the data rate poses challenges for online and offline reconstruction as well as for data compression. Compared to Run 2, the online farm must process 50 times more events per second and achieve a higher data compression factor. ALICE will rely on GPUs to perform real time processing and data compression of the Time Projection Chamber (TPC) detector in real time, the biggest contributor to the data rate. With GPUs available in the online farm, we are evaluating their usage also for the full tracking chain during the asynchronous reconstruction for the silicon Inner Tracking System (ITS) and Transition Radiation Detector (TRD). The software is written in a generic way, such that it can also run on processors on the WLCG with the same reconstruction output. We give an overview of the status and the current performance of the reconstruction and the data compression implementations on the GPU for the TPC and for the global reconstruction.
