Cross-platform In-Situ visualization system for runtime data exploration based on PBVR

Kawamura, Takuma ; Noda, Tomoyuki; Idomura, Yasuhiro   

We examine the performance portability of the In-Situ visualization system based on the Particle Based Volume Rendering (In-Situ PBVR). In this system, parallelized In-Situ processing converts extreme scale volume data into small rendering primitive data given by particles without costly visibility ordering, and the small particles can be rendered as view-independent volume rendering image on client user PC. These features enable us to avoid severe bottlenecks on latest many core platforms such as limited memory size per node and significant performance gap between computation and inter-node communication. The system shows excellent strong scaling up to about 50k threads on the Oakforest-PACS, which consists of 8,208 Intel Xeon Phi7250 (Knights Landing) processors. Asynchronous file based control sequences are designed to enable interactive and remote in-situ data exploration without interfering this strong scaling.