On Wed, Apr 06, 2011 at 02:01:17PM -0600, Leigh Orf wrote: > > You have to relink your application against the libipm.a that his > > produces (or you can enable the shared library and do an LD_PRELOAD). > > After you application runs, you'll have a text file for each MPI rank > > with the POSIX calls and their arguments. > > Is it possible that having 30,000 text files being written could actually > affect timings when trying to ascertain what's going on with I/O? If so, is > there any way around this?
It's the classic tradeoff: you can have a lightweight tracing approach that generates summaries of the behavior or you can record every operation (and potentially perturb the results). the Argonne 'darshan' project might give enough of a big picture summary, but it was designed foremost to be lightweight, not exhaustive: http://press.mcs.anl.gov/darshan/ -- Rob Latham Mathematics and Computer Science Division Argonne National Lab, IL USA _______________________________________________ Hdf-forum is for HDF software users discussion. [email protected] http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
