Scaling Score-P to the next level * *This material is based upon work supported by the US Department of Energy under Grant No. DE-SC0015524 and by the German Federal Ministry for Education and Research (BMBF) under Grant No. 01IH13001.
Daniel Lorenz, Christian Feld · Procedia Computer Science · 2017
As part of performance measurements with Score-P, a description of the system and the execution locations is recorded into the performance measurement reports. For large-scale measurements using a million or more processes, the global system description can consume all the available memory. While the information stored process-locally during measurement is small, the memory requirement becomes a bottleneck in the process of constructing a global representation of the whole system. To address this problem we implemented a new system description in Score-P that exploits regular structures of the system, and results, on homogeneous systems, in a system description of constant size. Furthermore, we present a parallel algorithm to create a global view from the process-local information. The scalable system description comes at the price that it is no longer possible to assign individual names to each system element, but only enumerate elements of the same type. We have successfully tested the new approach on the full JUQUEEN system with up to nearly two million processes.