As I mentioned, have you tried -cuda_initialize 0? Also, PetscCUDAInitialize contains
ierr = PetscCUBLASInitializeHandle();CHKERRQ(ierr); ierr = PetscCUSOLVERDnInitializeHandle();CHKERRQ(ierr); Have you tried to comment out them and test again? --Junchao Zhang On Sat, Feb 8, 2020 at 5:22 PM Zhang, Hong via petsc-dev < petsc-dev@mcs.anl.gov> wrote: > > > On Feb 8, 2020, at 5:03 PM, Matthew Knepley <knep...@gmail.com> wrote: > > On Sat, Feb 8, 2020 at 4:34 PM Zhang, Hong via petsc-dev < > petsc-dev@mcs.anl.gov> wrote: > >> I did some further investigation. The overhead persists for both the >> PETSc shared library and the static library. In the previous example, it >> does not call any PETSc function, the first CUDA function becomes very slow >> when it is linked to the petsc so. This indicates that the slowdown occurs >> if the symbol (cudafree)is searched through the petsc so, but does not >> occur if the symbol is found directly in the cuda runtime lib. >> >> So the issue has nothing to do with the dynamic linker. The following >> example can be used to easily reproduce the problem (cudaFree(0) always >> takes ~7.5 seconds). >> > > 1) This should go to OLCF admin as Jeff suggests > > > I had sent this to OLCF admin before the discussion was started here. > Thomas Papatheodore has followed up. I am trying to help him reproduce the > problem on summit. > > > 2) Just to make sure I understand, a static executable with this code is > still slow on the cudaFree(), since CUDA is a shared library by default. > > > I prepared the code as a minimal example to reproduce the problem. It > would be fair to say any code using PETSc (with CUDA enabled, built > statically or dynamically) on summit suffers a 7.5-second overhead on the > first CUDA function call (either in the user code or inside PETSc). > > Thanks, > Hong > > > I think we should try: > > a) Forcing a full static link, if possible > > b) Asking OLCF about link resolution order > > It sounds like a similar thing I have seen in the past where link > resolution order can exponentially increase load time. > > Thanks, > > Matt > > >> bash-4.2$ cat ex_simple_petsc.c >> #include <time.h> >> #include <cuda_runtime.h> >> #include <stdio.h> >> #include <petscmat.h> >> >> int main(int argc,char **args) >> { >> clock_t start,s1,s2,s3; >> double cputime; >> double *init,tmp[100] = {0}; >> PetscErrorCode ierr=0; >> >> ierr = PetscInitialize(&argc,&args,(char*)0,NULL);if (ierr) return ierr; >> 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); >> ierr = PetscFinalize(); >> return ierr; >> } >> >> Hong >> >> 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; >> } >> >> >> >> >> >> >> > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which their > experiments lead. > -- Norbert Wiener > > https://www.cse.buffalo.edu/~knepley/ > <http://www.cse.buffalo.edu/~knepley/> > > >