Online GPUAnalysis using Adaptive DMA Controlled by Softcore for 2D Detectors

New generation X-ray detectors enables cutting-edge experiments that can produce very high throughput data streams that are challenging to manage and store. This paper presents an evaluation of a configurable data placement mechanism from an FPGA device collecting detector raw data to a burst-cache memory and concurrently to a GPU accelerator, bypassing hardware and software extraneous copies and bottlenecks via PCI-Express. It includes a DMA controller dynamically configured in real-time by a Microblaze soft-processor. A low-latency synchronization mechanism using GPUDirect technology is presented as well. Multi-GB, DMA-able memory buffer allocation, leveraging Linux contiguous memory allocator is investigated. As illustrative workloads, real-time raw-data correction as foreseen in Serial Synchrotron X-ray experiments were processed. Obtained results showed that if one could reach a data throughput of 12.7GB/s to CPU memory when using PCIe gen3 x16, a 12-cores OpenMP CPU application processes the raw data only up to 2.7GB/s and is outperformed by a GPU accelerator (NVIDIA RTX 6000).