#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 dradice@…):
Ian, Erik,
hwloc is active in my ET_2014_11 runs, so this explains the difference. The two runs I mentioned before (with ET_2014_11 and ET_2015_05) are too different to meaningfully compare timers: I only verified that the ET_2014_11 was correctly using all CPU cores, while the ET_2015_05 without SystemTopology was placing all processes on the first socket.
It seems to me that activating SystemTopology should be the default behavior, because running on a workstation is not a common use case. This was also the old behavior of hwloc, so migrating from ET_2014_11 to ET_2015_05 brakes many production setups. When running on workstations, I used to remove hwloc from my thornlist exactly to avoid the problem Erik mention above.