#1850: Severe performance problem on Stampede -------------------------+-------------------------------------------------- Reporter: hinder | Owner: Type: defect | Status: review Priority: major | Milestone: Component: SimFactory | Version: development version Resolution: | Keywords: -------------------------+--------------------------------------------------
Comment (by knarf):
Replying to [comment:27 dradice@…]:
Activating SystemTopology would only be harmful if the user is running
multiple independent Cactus simulations on the same workstation. In that case, SystemTopology would place all Cactus instances on the same core and degrade performances significantly.
That is like - when running testsuites in parallel. I don't do that often though, but we did develop a script for it once. What would happen if SystemTopology isn't used in that case - the OS would distribute the processes, wouldn't it?
Would it be reasonable to let SystemTopology (by default) not enforce pinning when using "less than one full node"? Would it even be possible to always detect that situation correctly? Would not using SystemTopology in that case mean a performance hit? If so, how big would it probably be?