Brice I tried using this tarball. Things didn't work. (This particular run used 2 MPI processes with 32 OpenMP threads each.)
In my application, I first output the topology in a tree structure. (I do this in my application instead of via one of hwloc's tools because I don't want to call out to shell code.) Then I output thread bindings, then modify the thread bindings, then output them again. (1) The topology I find consists of 32 PUs and nothing else. I would have expected to find two cache levels, 16 cores, and 64 PUs. (2) When outputting the thread bindings, I received a segfault. The lightweight core file says this was signal 6 (SIGABRT) in a routine called ".raise". I'd be happy to help debug this. How? -erik On Sat, Feb 9, 2013 at 5:46 PM, Brice Goglin <brice.gog...@inria.fr> wrote: > The new "bgq" branch now contains proper topology for BG/Q nodes > (including cores and caches, except the prefetching cache) as well as > support for set/get binding of the current thread or of another thread. No > process-wide binding since I don't know how to iterate over all threads of > a process. > > A tarball is available at: > > https://ci.inria.fr/hwloc/job/hwloc-zcustom-tarball/lastSuccessfulBuild/artifact/hwloc-1.7a1r5312.tar.gz > (this is our new regression testing tool, I hope the tarball won't > disappear too soon) > > I don't expect a lot more features so this branch will likely go into > trunk very soon. But if you can look at it, that'll be great. > > > Brice > > > > 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 > > -- > Erik Schnetter <schnet...@gmail.com> > http://www.perimeterinstitute.ca/personal/eschnetter/ > > > _______________________________________________ > hwloc-users mailing > listhwloc-users@open-mpi.orghttp://www.open-mpi.org/mailman/listinfo.cgi/hwloc-users > > > -- Erik Schnetter <schnet...@gmail.com> http://www.perimeterinstitute.ca/personal/eschnetter/
