[petsc-dev] First call to cudaMalloc or cudaFree is very slow on summit
Junchao Zhang
jczhang at mcs.anl.gov
Fri Feb 7 20:37:24 CST 2020
Have you tried passing -cuda_initialize 0 to petsc?
--Junchao Zhang
On Fri, Feb 7, 2020 at 5:16 PM Zhang, Hong via petsc-dev <
petsc-dev at mcs.anl.gov> wrote:
> 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. <bsmith at 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 <hongzhang at 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 at 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. <bsmith at 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 at 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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