Hello Erik,
We need specific BGQ binding support, the binding API is different. Also we don't properly detect the 16 4-way cores properly, we only only 64 identical PUs.
I am supposed to get a BGQ account in the near future so I hope I will have everything working in v1.7.
Stay tuned

Le 08/01/2013 18:06, Erik Schnetter a écrit :
I am trying to use hwloc on a Blue Gene/Q. Building and installing worked fine, and it reports the system configuration fine as well (i.e. it shows all PUs). However, when I try to inquire the thread/core bindings, hwloc crashes with an error in libc's free(). This is both with 1.6 and 1.6.1rc1.

The error occurs apparently in CPU_FREE called from hwloc_linux_find_kernel_nr_cpus.

Does this ring a bell with anyone? I know this is not enough information to debug things, but do you have any pointers for things to look at?

I remember reading somewhere that the last bit in a cpu_set_t cannot be used. A Blue Gene/Q has 64 PUs, and may be using 64-bit integers to hold cpu_set_t data. Could this be an issue?

My goal is to examine and experiment with thread/core bindings with OpenMP to improve performance.


Erik Schnetter <schnetter@gmail.com> http://www.perimeterinstitute.ca/personal/eschnetter/

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