title: OpenMPI debugging with Valgrind and suppressions in OS X
body: <p>I am writing a parallel code in C++ on my OS X (Snow Leopard) laptop, and I am trying to debug it with memchecker. I have successfully built OpenMPI with valgrind support with: <code>configure --prefix=/opt/openmpi-1.4.3/ --enable-debug --enable-memchecker --with-valgrind=/opt/valgrind-3.6.0/ FFLAGS=-m64 F90FLAGS=-m64</code> (Ignore the Fortran flags, it's due to my Fortran compiler being from GCC).</p>
  
  <p>When I run my application with</p>
  
  <blockquote>
    <p>mpirun -np 2 valgrind --suppressions=/opt/openmpi-1.4.3/share/openmpi/openmpi-valgrind.supp --leak-check=yes --dsymutil=yes ./program</p>
  </blockquote>
  
  <p>I get a whole lot of warnings from Valgrind (the most of them from the heap summary at the end). I have included a small snippet of the warnings below. What I get from them is that Valgrind detects memory leaks and uninitialised values in the MPI library, but I'm not really interested in that. I want warnings from the code I write. I already run Valgrind with the suppression file provided by OpenMPI, but evidently it is not enough. How can I easily ignore all the other warnings detected in  the OpenMPI distribution? Is it possible to find a suppression file for OpenMPI debugging with Valgrind on OS X, or do you know any cunning trick?</p>
  
  <p>The first warning is</p>
  
  <pre><code> ==1531==    Syscall param writev(vector[...]) points to uninitialised byte(s)
   ==1531==    at 0x1014E16E2: writev (in /usr/lib/libSystem.B.dylib)
   ==1531==    by 0x101AEA4C5: mca_oob_tcp_peer_send (in /opt/openmpi-1.4.3/lib/openmpi/mca_oob_tcp.so)
   ==1531==    by 0x101AF0B88: mca_oob_tcp_send_nb (in /opt/openmpi-1.4.3/lib/openmpi/mca_oob_tcp.so)
   ==1531==    by 0x101AC7F48: orte_rml_oob_send (in /opt/openmpi-1.4.3/lib/openmpi/mca_rml_oob.so)
   ==1531==    by 0x101AC8AA1: orte_rml_oob_send_buffer (in /opt/openmpi-1.4.3/lib/openmpi/mca_rml_oob.so)
   ==1531==    by 0x101B3489E: allgather (in /opt/openmpi-1.4.3/lib/openmpi/mca_grpcomm_bad.so) 
   ==1531==    by 0x101B3525D: modex (in /opt/openmpi-1.4.3/lib/openmpi/mca_grpcomm_bad.so)
   ==1531==    by 0x1000A48E6: ompi_mpi_init (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x1000F7806: MPI_Init (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100001AF2: main (main.cpp:34)
   ==1531==  Address 0x101a8911b is 107 bytes inside a block of size 256 alloc'd
   ==1531==    at 0x10002DB2D: realloc (vg_replace_malloc.c:525)
   ==1531==    by 0x1012240B6: opal_dss_buffer_extend (in /opt/openmpi-1.4.3/lib/libopen- pal.0.dylib)
   ==1531==    by 0x101225CF7: opal_dss_copy_payload (in /opt/openmpi-1.4.3/lib/libopen-pal.0.dylib)
   ==1531==    by 0x101B347CA: allgather (in /opt/openmpi-1.4.3/lib/openmpi/mca_grpcomm_bad.so)
   ==1531==    by 0x101B3525D: modex (in /opt/openmpi-1.4.3/lib/openmpi/mca_grpcomm_bad.so)
   ==1531==    by 0x1000A48E6: ompi_mpi_init (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x1000F7806: MPI_Init (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100001AF2: main (main.cpp:34)
  </code></pre>
  
  <p>After execution a small snippet of the heap summary looks like this</p>
  
  <pre><code> ==1531== 88 bytes in 1 blocks are definitely lost in loss record 1,950 of 2,194
   ==1531==    at 0x10002D915: malloc (vg_replace_malloc.c:236)
   ==1531==    by 0x100073888: opal_obj_new (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100073808: opal_obj_new_debug (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100073C17: ompi_attr_create_keyval_impl (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100073FCF: ompi_attr_create_keyval (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100077C96: create_comm (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x10007798A: ompi_attr_create_predefined (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x1000737CF: ompi_attr_init (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x1000A4840: ompi_mpi_init (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x1000F7806: MPI_Init (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100001AF2: main (main.cpp:34)
  </code></pre>
  
  <blockquote>
    <p>...</p>
  </blockquote>
  
  <pre><code> ==1531== 88 bytes in 1 blocks are definitely lost in loss record 1,952 of 2,194
   ==1531==    at 0x10002D915: malloc (vg_replace_malloc.c:236)
   ==1531==    by 0x100073888: opal_obj_new (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100073808: opal_obj_new_debug (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100073C17: ompi_attr_create_keyval_impl (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100073FCF: ompi_attr_create_keyval (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x10014CEC5: PMPI_Keyval_create (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x1065ACFE6: ???
   ==1531==    by 0x10658867B: ???
   ==1531==    by 0x10017A591: module_init (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100179985: mca_io_base_file_select (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100089D55: ompi_file_open (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x1000E1ED1: MPI_File_open (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531== 
   ==1531== 88 bytes in 1 blocks are definitely lost in loss record 1,953 of 2,194
   ==1531==    at 0x10002D915: malloc (vg_replace_malloc.c:236)
   ==1531==    by 0x100073888: opal_obj_new (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100073808: opal_obj_new_debug (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100073C17: ompi_attr_create_keyval_impl (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x100073FCF: ompi_attr_create_keyval (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x10014CEC5: PMPI_Keyval_create (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
   ==1531==    by 0x1065A6210: ???
   ==1531==    by 0x106597149: ???
   ==1531==    by 0x106596AAB: ???
   ==1531==    by 0x1065AD14C: ???
   ==1531==    by 0x10658867B: ???
   ==1531==    by 0x10017A591: module_init (in /opt/openmpi-1.4.3/lib/libmpi.0.dylib)
  </code></pre>