Hi Quincey, a tracing feature in HDF5 would be pretty helpful, and easier to use than IPM. There is a similar feature available in the Cray MPI-IO library,where you can set the environment variables
MPICH_MPIIO_XSTATS to 1 or 2 to get detailed output of how the data is aggregated and written from the the CB nodes (there's more information available from the Cray document here: http://docs.cray.com/books/S-0013-10/). But this wouldn't report on chunking or independent I/O through HDF5. Mark On Mon, Mar 7, 2011 at 11:07 AM, Quincey Koziol <[email protected]> wrote: > Hi all, > > On Mar 4, 2011, at 2:22 PM, Rob Latham wrote: > >> On Fri, Mar 04, 2011 at 10:09:14AM -0500, Mark Howison wrote: >>> Hi Matthieu, >>> >>> The Integrated Performance Monitor (IPM) v2 beta has a POSIX I/O >>> tracing feature. This will give you detailed output of the underlying >>> POSIX calls (such as open, write and read) made by your application >>> (through the pHDF layer). You can download it here: >>> >>> http://tools.pub.lab.nm.ifi.lmu.de/web/ipm/ >>> >>> To enable I/O tracing, you have to configure with >>> >>> ./configure --enable-posixio CFLAGS=-DHAVE_POSIXIO_TRACE >>> >>> 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. >> >> Matthieu Dorier was asking for a tuple of (rank,file,offset,size). >> >> I guess this really belongs on the ipm-hpc-help list, but IPM doesn't >> actually give you the offset information. It wraps fseek(3) but HDF5 >> using MPI-IO is probably going to call lseek(2), lseek64(2) some other >> seek-like system call. >> >> IPM is pretty close, giving the file, size, and a timestamp all tucked >> into a file-per-rank. > > We've got a small project currently in the works that gives a minimal > amount of information back to the application: whether a collective I/O > write/read operation completed as a collective, or was broken down into an > independent operation (or some combination of those two, for chunked > datasets); which should help some. I don't think we've got direct funding > for more effort in this direction currently, but I'd sure like to roll it > into a new set of funding (or work with someone who feels like submitting a > patch for this idea). > > Quincey > > > _______________________________________________ > Hdf-forum is for HDF software users discussion. > [email protected] > http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org > _______________________________________________ Hdf-forum is for HDF software users discussion. [email protected] http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
