I tried to install PETSc shared library in /gpfs/alpine/scratch, which should 
be faster than the home directory. But the same overhead still persists.

Hong

> On Feb 7, 2020, at 4:32 PM, Smith, Barry F. <bsm...@mcs.anl.gov> wrote:
> 
> 
>   Perhaps the intent is that you build or install (--prefix) your libraries 
> in a different place than /autofs/nccs-svm1_home1 
> 
> 
> 
>> On Feb 7, 2020, at 3:09 PM, Zhang, Hong <hongzh...@anl.gov> wrote:
>> 
>> Note that the overhead was triggered by the first call to a CUDA function. 
>> So it seems that the first CUDA function triggered loading petsc so (if 
>> petsc so is linked), which is slow on the summit file system.
>> 
>> Hong
>> 
>>> On Feb 7, 2020, at 2:54 PM, Zhang, Hong via petsc-dev 
>>> <petsc-dev@mcs.anl.gov> wrote:
>>> 
>>> Linking any other shared library does not slow down the execution. The 
>>> PETSc shared library is the only one causing trouble.
>>> 
>>> Here are the ldd output for two different versions. For the first version, 
>>> I removed -lpetsc and it ran very fast. The second (slow) version was 
>>> linked to petsc so. 
>>> 
>>> bash-4.2$ ldd ex_simple
>>>        linux-vdso64.so.1 =>  (0x0000200000050000)
>>>        liblapack.so.0 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/liblapack.so.0
>>>  (0x0000200000070000)
>>>        libblas.so.0 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libblas.so.0
>>>  (0x00002000009b0000)
>>>        libhdf5hl_fortran.so.100 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/hdf5-1.10.3-pgiul2yf4auv7krecd72t6vupd7e3qgn/lib/libhdf5hl_fortran.so.100
>>>  (0x0000200000e80000)
>>>        libhdf5_fortran.so.100 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/hdf5-1.10.3-pgiul2yf4auv7krecd72t6vupd7e3qgn/lib/libhdf5_fortran.so.100
>>>  (0x0000200000ed0000)
>>>        libhdf5_hl.so.100 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/hdf5-1.10.3-pgiul2yf4auv7krecd72t6vupd7e3qgn/lib/libhdf5_hl.so.100
>>>  (0x0000200000f50000)
>>>        libhdf5.so.103 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/hdf5-1.10.3-pgiul2yf4auv7krecd72t6vupd7e3qgn/lib/libhdf5.so.103
>>>  (0x0000200000fb0000)
>>>        libX11.so.6 => /usr/lib64/libX11.so.6 (0x00002000015e0000)
>>>        libcufft.so.10 => /sw/summit/cuda/10.1.168/lib64/libcufft.so.10 
>>> (0x0000200001770000)
>>>        libcublas.so.10 => /sw/summit/cuda/10.1.168/lib64/libcublas.so.10 
>>> (0x0000200009b00000)
>>>        libcudart.so.10.1 => 
>>> /sw/summit/cuda/10.1.168/lib64/libcudart.so.10.1 (0x000020000d950000)
>>>        libcusparse.so.10 => 
>>> /sw/summit/cuda/10.1.168/lib64/libcusparse.so.10 (0x000020000d9f0000)
>>>        libcusolver.so.10 => 
>>> /sw/summit/cuda/10.1.168/lib64/libcusolver.so.10 (0x0000200012f50000)
>>>        libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x000020001dc40000)
>>>        libdl.so.2 => /usr/lib64/libdl.so.2 (0x000020001ddd0000)
>>>        libpthread.so.0 => /usr/lib64/libpthread.so.0 (0x000020001de00000)
>>>        libmpiprofilesupport.so.3 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libmpiprofilesupport.so.3
>>>  (0x000020001de40000)
>>>        libmpi_ibm_usempi.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libmpi_ibm_usempi.so
>>>  (0x000020001de70000)
>>>        libmpi_ibm_mpifh.so.3 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libmpi_ibm_mpifh.so.3
>>>  (0x000020001dea0000)
>>>        libmpi_ibm.so.3 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libmpi_ibm.so.3
>>>  (0x000020001df40000)
>>>        libpgf90rtl.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgf90rtl.so
>>>  (0x000020001e0b0000)
>>>        libpgf90.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgf90.so
>>>  (0x000020001e0f0000)
>>>        libpgf90_rpm1.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgf90_rpm1.so
>>>  (0x000020001e6a0000)
>>>        libpgf902.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgf902.so
>>>  (0x000020001e6d0000)
>>>        libpgftnrtl.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgftnrtl.so
>>>  (0x000020001e700000)
>>>        libatomic.so.1 => /usr/lib64/libatomic.so.1 (0x000020001e730000)
>>>        libpgkomp.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgkomp.so
>>>  (0x000020001e760000)
>>>        libomp.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libomp.so
>>>  (0x000020001e790000)
>>>        libomptarget.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libomptarget.so
>>>  (0x000020001e880000)
>>>        libpgmath.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgmath.so
>>>  (0x000020001e8b0000)
>>>        libpgc.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgc.so
>>>  (0x000020001e9d0000)
>>>        librt.so.1 => /usr/lib64/librt.so.1 (0x000020001eb40000)
>>>        libm.so.6 => /usr/lib64/libm.so.6 (0x000020001eb70000)
>>>        libgcc_s.so.1 => /usr/lib64/libgcc_s.so.1 (0x000020001ec60000)
>>>        libc.so.6 => /usr/lib64/libc.so.6 (0x000020001eca0000)
>>>        libz.so.1 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/zlib-1.2.11-2htm7ws4hgrthi5tyjnqxtjxgpfklxsc/lib/libz.so.1
>>>  (0x000020001ee90000)
>>>        libxcb.so.1 => /usr/lib64/libxcb.so.1 (0x000020001eef0000)
>>>        /lib64/ld64.so.2 (0x0000200000000000)
>>>        libcublasLt.so.10 => 
>>> /sw/summit/cuda/10.1.168/lib64/libcublasLt.so.10 (0x000020001ef40000)
>>>        libutil.so.1 => /usr/lib64/libutil.so.1 (0x0000200020e50000)
>>>        libhwloc_ompi.so.15 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libhwloc_ompi.so.15
>>>  (0x0000200020e80000)
>>>        libevent-2.1.so.6 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libevent-2.1.so.6
>>>  (0x0000200020ef0000)
>>>        libevent_pthreads-2.1.so.6 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libevent_pthreads-2.1.so.6
>>>  (0x0000200020f70000)
>>>        libopen-rte.so.3 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libopen-rte.so.3
>>>  (0x0000200020fa0000)
>>>        libopen-pal.so.3 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libopen-pal.so.3
>>>  (0x00002000210b0000)
>>>        libXau.so.6 => /usr/lib64/libXau.so.6 (0x00002000211a0000)
>>> 
>>> 
>>> bash-4.2$ ldd ex_simple_slow
>>>        linux-vdso64.so.1 =>  (0x0000200000050000)
>>>        libpetsc.so.3.012 => 
>>> /autofs/nccs-svm1_home1/hongzh/Projects/petsc/arch-olcf-summit-sell-opt/lib/libpetsc.so.3.012
>>>  (0x0000200000070000)
>>>        liblapack.so.0 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/liblapack.so.0
>>>  (0x0000200002be0000)
>>>        libblas.so.0 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libblas.so.0
>>>  (0x0000200003520000)
>>>        libhdf5hl_fortran.so.100 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/hdf5-1.10.3-pgiul2yf4auv7krecd72t6vupd7e3qgn/lib/libhdf5hl_fortran.so.100
>>>  (0x00002000039f0000)
>>>        libhdf5_fortran.so.100 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/hdf5-1.10.3-pgiul2yf4auv7krecd72t6vupd7e3qgn/lib/libhdf5_fortran.so.100
>>>  (0x0000200003a40000)
>>>        libhdf5_hl.so.100 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/hdf5-1.10.3-pgiul2yf4auv7krecd72t6vupd7e3qgn/lib/libhdf5_hl.so.100
>>>  (0x0000200003ac0000)
>>>        libhdf5.so.103 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/hdf5-1.10.3-pgiul2yf4auv7krecd72t6vupd7e3qgn/lib/libhdf5.so.103
>>>  (0x0000200003b20000)
>>>        libX11.so.6 => /usr/lib64/libX11.so.6 (0x0000200004150000)
>>>        libcufft.so.10 => /sw/summit/cuda/10.1.168/lib64/libcufft.so.10 
>>> (0x00002000042e0000)
>>>        libcublas.so.10 => /sw/summit/cuda/10.1.168/lib64/libcublas.so.10 
>>> (0x000020000c670000)
>>>        libcudart.so.10.1 => 
>>> /sw/summit/cuda/10.1.168/lib64/libcudart.so.10.1 (0x00002000104c0000)
>>>        libcusparse.so.10 => 
>>> /sw/summit/cuda/10.1.168/lib64/libcusparse.so.10 (0x0000200010560000)
>>>        libcusolver.so.10 => 
>>> /sw/summit/cuda/10.1.168/lib64/libcusolver.so.10 (0x0000200015ac0000)
>>>        libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x00002000207b0000)
>>>        libdl.so.2 => /usr/lib64/libdl.so.2 (0x0000200020940000)
>>>        libpthread.so.0 => /usr/lib64/libpthread.so.0 (0x0000200020970000)
>>>        libmpiprofilesupport.so.3 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libmpiprofilesupport.so.3
>>>  (0x00002000209b0000)
>>>        libmpi_ibm_usempi.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libmpi_ibm_usempi.so
>>>  (0x00002000209e0000)
>>>        libmpi_ibm_mpifh.so.3 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libmpi_ibm_mpifh.so.3
>>>  (0x0000200020a10000)
>>>        libmpi_ibm.so.3 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libmpi_ibm.so.3
>>>  (0x0000200020ab0000)
>>>        libpgf90rtl.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgf90rtl.so
>>>  (0x0000200020c20000)
>>>        libpgf90.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgf90.so
>>>  (0x0000200020c60000)
>>>        libpgf90_rpm1.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgf90_rpm1.so
>>>  (0x0000200021210000)
>>>        libpgf902.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgf902.so
>>>  (0x0000200021240000)
>>>        libpgftnrtl.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgftnrtl.so
>>>  (0x0000200021270000)
>>>        libatomic.so.1 => /usr/lib64/libatomic.so.1 (0x00002000212a0000)
>>>        libpgkomp.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgkomp.so
>>>  (0x00002000212d0000)
>>>        libomp.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libomp.so
>>>  (0x0000200021300000)
>>>        libomptarget.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libomptarget.so
>>>  (0x00002000213f0000)
>>>        libpgmath.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgmath.so
>>>  (0x0000200021420000)
>>>        libpgc.so => 
>>> /autofs/nccs-svm1_sw/summit/.swci/0-core/opt/spack/20180914/linux-rhel7-ppc64le/gcc-4.8.5/pgi-19.4-6acz4xyqjlpoaonjiiqjme2aknrfnzoy/linuxpower/19.4/lib/libpgc.so
>>>  (0x0000200021540000)
>>>        librt.so.1 => /usr/lib64/librt.so.1 (0x00002000216b0000)
>>>        libm.so.6 => /usr/lib64/libm.so.6 (0x00002000216e0000)
>>>        libgcc_s.so.1 => /usr/lib64/libgcc_s.so.1 (0x00002000217d0000)
>>>        libc.so.6 => /usr/lib64/libc.so.6 (0x0000200021810000)
>>>        libz.so.1 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/zlib-1.2.11-2htm7ws4hgrthi5tyjnqxtjxgpfklxsc/lib/libz.so.1
>>>  (0x0000200021a10000)
>>>        libxcb.so.1 => /usr/lib64/libxcb.so.1 (0x0000200021a60000)
>>>        /lib64/ld64.so.2 (0x0000200000000000)
>>>        libcublasLt.so.10 => 
>>> /sw/summit/cuda/10.1.168/lib64/libcublasLt.so.10 (0x0000200021ab0000)
>>>        libutil.so.1 => /usr/lib64/libutil.so.1 (0x00002000239c0000)
>>>        libhwloc_ompi.so.15 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libhwloc_ompi.so.15
>>>  (0x00002000239f0000)
>>>        libevent-2.1.so.6 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libevent-2.1.so.6
>>>  (0x0000200023a60000)
>>>        libevent_pthreads-2.1.so.6 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libevent_pthreads-2.1.so.6
>>>  (0x0000200023ae0000)
>>>        libopen-rte.so.3 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libopen-rte.so.3
>>>  (0x0000200023b10000)
>>>        libopen-pal.so.3 => 
>>> /autofs/nccs-svm1_sw/summit/.swci/1-compute/opt/spack/20180914/linux-rhel7-ppc64le/pgi-19.4/spectrum-mpi-10.3.0.1-20190611-4ymaahbai7ehhw4rves5jjiwon2laz3a/lib/libopen-pal.so.3
>>>  (0x0000200023c20000)
>>>        libXau.so.6 => /usr/lib64/libXau.so.6 (0x0000200023d10000)
>>> 
>>> 
>>>> On Feb 7, 2020, at 2:31 PM, Smith, Barry F. <bsm...@mcs.anl.gov> wrote:
>>>> 
>>>> 
>>>> ldd -o on the executable of both linkings of your code.
>>>> 
>>>> My guess is that without PETSc it is linking the static version of the 
>>>> needed libraries and with PETSc the shared. And, in typical fashion, the 
>>>> shared libraries are off on some super slow file system so take a long 
>>>> time to be loaded and linked in on demand.
>>>> 
>>>>  Still a performance bug in Summit. 
>>>> 
>>>>  Barry
>>>> 
>>>> 
>>>>> On Feb 7, 2020, at 12:23 PM, Zhang, Hong via petsc-dev 
>>>>> <petsc-dev@mcs.anl.gov> wrote:
>>>>> 
>>>>> Hi all,
>>>>> 
>>>>> Previously I have noticed that the first call to a CUDA function such as 
>>>>> cudaMalloc and cudaFree in PETSc takes a long time (7.5 seconds) on 
>>>>> summit. Then I prepared a simple example as attached to help OCLF 
>>>>> reproduce the problem. It turned out that the problem was  caused by 
>>>>> PETSc. The 7.5-second overhead can be observed only when the PETSc lib is 
>>>>> linked. If I do not link PETSc, it runs normally. Does anyone have any 
>>>>> idea why this happens and how to fix it?
>>>>> 
>>>>> Hong (Mr.)
>>>>> 
>>>>> bash-4.2$ cat ex_simple.c
>>>>> #include <time.h>
>>>>> #include <cuda_runtime.h>
>>>>> #include <stdio.h>
>>>>> 
>>>>> int main(int argc,char **args)
>>>>> {
>>>>> clock_t start,s1,s2,s3;
>>>>> double  cputime;
>>>>> double   *init,tmp[100] = {0};
>>>>> 
>>>>> start = clock();
>>>>> cudaFree(0);
>>>>> s1 = clock();
>>>>> cudaMalloc((void **)&init,100*sizeof(double));
>>>>> s2 = clock();
>>>>> cudaMemcpy(init,tmp,100*sizeof(double),cudaMemcpyHostToDevice);
>>>>> s3 = clock();
>>>>> printf("free time =%lf malloc time =%lf copy time =%lf\n",((double) (s1 - 
>>>>> start)) / CLOCKS_PER_SEC,((double) (s2 - s1)) / CLOCKS_PER_SEC,((double) 
>>>>> (s3 - s2)) / CLOCKS_PER_SEC);
>>>>> 
>>>>> return 0;
>>>>> }
>>>>> 
>>>>> 
>>>> 
>>> 
>> 
> 

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