Le 25/03/2014 07:51, Biddiscombe, John A. a écrit : > > I'm compiling hwloc using clang (bgclang++11 from ANL) to run on IO > nodes af a BGQ. It seems to have compiled ok, and when I run lstopo, I > get an output like this (below), which looks reasonable, but there are > 15 sockets instead of 16. I'm a little worried because the first time > I compiled, I had problems where apps would report an error from HWLOC > on start and tell me to set HWLOC_FORCE_BGQ=1. when I did set this env > var, it would then report that "topology became empty" and the app > would segfault due to the unexpected return from hwloc presumably. >
Can you give a bit more details on what you did there? I'd like to check if that case should be better supported or not. > I wiped everything and recompiled (not sure what I did differently), > and now it behaves more sensibly, but with 15 instead of 16 sockets. > > > > Should IO be worried? > The topology detection is hardwired so you shouldn't worried on the hardware side. The problem could be related to how you reserved resources before running lstopo. Does lstopo --whole-system see more sockets? Does BG_THREADMODEL=2 help? Brice
